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Wang D, Rastas P, Yi X, Löytynoja A, Kivikoski M, Feng X, Reid K, Merilä J. Improved assembly of the Pungitius pungitius reference genome. G3 (BETHESDA, MD.) 2024; 14:jkae126. [PMID: 38861393 PMCID: PMC11304971 DOI: 10.1093/g3journal/jkae126] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/24/2024] [Revised: 05/23/2024] [Accepted: 05/30/2024] [Indexed: 06/13/2024]
Abstract
The nine-spined stickleback (Pungitius pungitius) has been increasingly used as a model system in studies of local adaptation and sex chromosome evolution but its current reference genome assembly is far from perfect, lacking distinct sex chromosomes. We generated an improved assembly of the nine-spined stickleback reference genome (98.3% BUSCO completeness) with the aid of linked-read mapping. While the new assembly (v8) was of similar size as the earlier version (v7), we were able to assign 4.4 times more contigs to the linkage groups and improve the contiguity of the genome. Moreover, the new assembly contains a ∼22.8 Mb Y-linked scaffold (LG22) consisting mainly of previously assigned X-contigs, putative Y-contigs, putative centromere contigs, and highly repetitive elements. The male individual showed an even mapping depth on LG12 (pseudo X chromosome) and LG22 (Y-linked scaffold) in the segregating sites, suggesting near-pure X and Y representation in the v8 assembly. A total of 26,803 genes were annotated, and about 33% of the assembly was found to consist of repetitive elements. The high proportion of repetitive elements in LG22 (53.10%) suggests it can be difficult to assemble the complete sequence of the species' Y chromosome. Nevertheless, the new assembly is a significant improvement over the previous version and should provide a valuable resource for genomic studies of stickleback fishes.
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Affiliation(s)
- Dandan Wang
- Area of Ecology and Biodiversity, School of Biological Sciences, The University of Hong Kong, 999077, Hong Kong SAR
| | - Pasi Rastas
- Institute of Biotechnology, University of Helsinki, Helsinki FI-00014, Finland
| | - Xueling Yi
- Area of Ecology and Biodiversity, School of Biological Sciences, The University of Hong Kong, 999077, Hong Kong SAR
| | - Ari Löytynoja
- Institute of Biotechnology, University of Helsinki, Helsinki FI-00014, Finland
- Organismal and Evolutionary Biology Research Programme, Faculty of Biological and Environmental Sciences, University of Helsinki, Helsinki FI-00014, Finland
| | - Mikko Kivikoski
- Ecological Genetics Research Unit, Organismal and Evolutionary Biology Research Programme, Faculty of Biological and Environmental Sciences, University of Helsinki, Helsinki FI-00014, Finland
- Department of Computer Science, University of Helsinki, Helsinki FI-00014, Finland
| | - Xueyun Feng
- Institute of Biotechnology, University of Helsinki, Helsinki FI-00014, Finland
- Ecological Genetics Research Unit, Organismal and Evolutionary Biology Research Programme, Faculty of Biological and Environmental Sciences, University of Helsinki, Helsinki FI-00014, Finland
| | - Kerry Reid
- Area of Ecology and Biodiversity, School of Biological Sciences, The University of Hong Kong, 999077, Hong Kong SAR
| | - Juha Merilä
- Area of Ecology and Biodiversity, School of Biological Sciences, The University of Hong Kong, 999077, Hong Kong SAR
- Ecological Genetics Research Unit, Organismal and Evolutionary Biology Research Programme, Faculty of Biological and Environmental Sciences, University of Helsinki, Helsinki FI-00014, Finland
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2
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Tan HZ, Scherer P, Stuart KC, Bailey S, Lee KD, Brekke P, Ewen JG, Whibley A, Santure AW. A high-density linkage map reveals broad- and fine-scale sex differences in recombination in the hihi (stitchbird; Notiomystis cincta). Heredity (Edinb) 2024:10.1038/s41437-024-00711-3. [PMID: 39095652 DOI: 10.1038/s41437-024-00711-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2024] [Revised: 07/23/2024] [Accepted: 07/24/2024] [Indexed: 08/04/2024] Open
Abstract
Recombination, the process of DNA exchange between homologous chromosomes during meiosis, plays a major role in genomic diversity and evolutionary change. Variation in recombination rate is widespread despite recombination often being essential for progression of meiosis. One such variation is heterochiasmy, where recombination rates differ between sexes. Heterochiasmy has been observed across broad taxonomic groups, yet it remains an evolutionary enigma. We used Lep-MAP3, a pedigree-based software that is efficient in handling large datasets, to generate linkage maps for the hihi or stitchbird (Notiomystis cincta), utilising information from >36 K SNPs and 36 families. We constructed 29 linkage maps, including for the previously unscaffolded Z chromosome. The hihi is an endangered passerine endemic to Aotearoa New Zealand that is sexually dimorphic and exhibits high levels of sexual conflict, including sperm competition. Patterns in recombination in the hihi are consistent with those in other birds, including higher recombination rates in micro-chromosomes. Heterochiasmy in the hihi is male-biased, in line with predictions of the Haldane-Huxley rule, with the male linkage map being 15% longer. Micro-chromosomes exhibit heterochiasmy to a greater extent, contrary to that reported in other birds. At the intra-chromosomal level, heterochiasmy is higher nearer to chromosome ends and in gene-rich regions. Regions of extreme heterochiasmy are enriched for genes implicated in cell structure. This study adds an important contribution in assessing evolutionary theories of heterochiasmy and provides a framework for future studies investigating fine-scale heterochiasmy.
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Affiliation(s)
- Hui Zhen Tan
- School of Biological Sciences, University of Auckland, Auckland, New Zealand
- Centre for Biodiversity and Biosecurity (CBB), School of Biological Sciences, University of Auckland, Auckland, New Zealand
| | - Phoebe Scherer
- School of Biological Sciences, University of Auckland, Auckland, New Zealand
| | - Katarina C Stuart
- School of Biological Sciences, University of Auckland, Auckland, New Zealand
| | - Sarah Bailey
- School of Biological Sciences, University of Auckland, Auckland, New Zealand
| | - Kate D Lee
- School of Biological Sciences, University of Auckland, Auckland, New Zealand
| | - Patricia Brekke
- Institute of Zoology, Zoological Society of London, London, UK
| | - John G Ewen
- Institute of Zoology, Zoological Society of London, London, UK
| | - Annabel Whibley
- School of Biological Sciences, University of Auckland, Auckland, New Zealand
- Bragato Research Institute, Lincoln, New Zealand
| | - Anna W Santure
- School of Biological Sciences, University of Auckland, Auckland, New Zealand.
- Centre for Biodiversity and Biosecurity (CBB), School of Biological Sciences, University of Auckland, Auckland, New Zealand.
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3
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Manthey JD, Spellman GM. Recombination rate variation shapes genomic variability of phylogeographic structure in a widespread North American songbird (Aves: Certhia americana). Mol Phylogenet Evol 2024; 196:108088. [PMID: 38697377 DOI: 10.1016/j.ympev.2024.108088] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2024] [Revised: 04/11/2024] [Accepted: 04/24/2024] [Indexed: 05/05/2024]
Abstract
The nonrandom distribution of chromosomal characteristics and functional elements-genomic architecture-impacts the relative strengths and impacts of population genetic processes across the genome. Due to this relationship, genomic architecture has the potential to shape variation in population genetic structure across the genome. Population genetic structure has been shown to vary across the genome in a variety of taxa, but this body of work has largely focused on pairwise population genomic comparisons between closely related taxa. Here, we used whole genome sequencing of seven phylogeographically structured populations of a North American songbird, the Brown Creeper (Certhia americana), to determine the impacts of genomic architecture on phylogeographic structure variation across the genome. Using multiple methods to infer phylogeographic structure-ordination, clustering, and phylogenetic methods-we found that recombination rate variation explained a large proportion of phylogeographic structure variation. Genomic regions with low recombination showed phylogeographic structure consistent with the genome-wide pattern. In regions with high recombination, we found strong phylogeographic structure, but with discordant patterns relative to the genome-wide pattern. In regions with high recombination rate, we found that populations with small effective population sizes evolve relatively more rapidly than larger populations, leading to discordant signatures of phylogeographic structure. These results suggest that the interplay between recombination rate variation and effective population sizes shape the relative impacts of selection and genetic drift in different parts of the genome. Overall, the combined interactions of population genetic processes, genomic architecture, and effective population sizes shape patterns of variability in phylogeographic structure across the genome of the Brown Creeper.
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Affiliation(s)
- Joseph D Manthey
- Department of Biological Sciences, Texas Tech University. Lubbock, TX, USA.
| | - Garth M Spellman
- Department of Zoology, Denver Museum of Nature & Science, Denver, CO, USA
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4
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Soni V, Jensen JD. Temporal challenges in detecting balancing selection from population genomic data. G3 (BETHESDA, MD.) 2024; 14:jkae069. [PMID: 38551137 DOI: 10.1093/g3journal/jkae069] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/21/2023] [Revised: 12/21/2023] [Accepted: 03/19/2024] [Indexed: 04/28/2024]
Abstract
The role of balancing selection in maintaining genetic variation remains an open question in population genetics. Recent years have seen numerous studies identifying candidate loci potentially experiencing balancing selection, most predominantly in human populations. There are however numerous alternative evolutionary processes that may leave similar patterns of variation, thereby potentially confounding inference, and the expected signatures of balancing selection additionally change in a temporal fashion. Here we use forward-in-time simulations to quantify expected statistical power to detect balancing selection using both site frequency spectrum- and linkage disequilibrium-based methods under a variety of evolutionarily realistic null models. We find that whilst site frequency spectrum-based methods have little power immediately after a balanced mutation begins segregating, power increases with time since the introduction of the balanced allele. Conversely, linkage disequilibrium-based methods have considerable power whilst the allele is young, and power dissipates rapidly as the time since introduction increases. Taken together, this suggests that site frequency spectrum-based methods are most effective at detecting long-term balancing selection (>25N generations since the introduction of the balanced allele) whilst linkage disequilibrium-based methods are effective over much shorter timescales (<1N generations), thereby leaving a large time frame over which current methods have little power to detect the action of balancing selection. Finally, we investigate the extent to which alternative evolutionary processes may mimic these patterns, and demonstrate the need for caution in attempting to distinguish the signatures of balancing selection from those of both neutral processes (e.g. population structure and admixture) as well as of alternative selective processes (e.g. partial selective sweeps).
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Affiliation(s)
- Vivak Soni
- School of Life Sciences, Center for Evolution & Medicine, Arizona State University, Tempe, AZ 85281, USA
| | - Jeffrey D Jensen
- School of Life Sciences, Center for Evolution & Medicine, Arizona State University, Tempe, AZ 85281, USA
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5
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Boman J, Qvarnström A, Mugal CF. Regulatory and evolutionary impact of DNA methylation in two songbird species and their naturally occurring F 1 hybrids. BMC Biol 2024; 22:124. [PMID: 38807214 PMCID: PMC11134931 DOI: 10.1186/s12915-024-01920-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2024] [Accepted: 05/15/2024] [Indexed: 05/30/2024] Open
Abstract
BACKGROUND Regulation of transcription by DNA methylation in 5'-CpG-3' context is a widespread mechanism allowing differential expression of genetically identical cells to persist throughout development. Consequently, differences in DNA methylation can reinforce variation in gene expression among cells, tissues, populations, and species. Despite a surge in studies on DNA methylation, we know little about the importance of DNA methylation in population differentiation and speciation. Here we investigate the regulatory and evolutionary impact of DNA methylation in five tissues of two Ficedula flycatcher species and their naturally occurring F1 hybrids. RESULTS We show that the density of CpG in the promoters of genes determines the strength of the association between DNA methylation and gene expression. The impact of DNA methylation on gene expression varies among tissues with the brain showing unique patterns. Differentially expressed genes between parental species are predicted by genetic and methylation differentiation in CpG-rich promoters. However, both these factors fail to predict hybrid misexpression suggesting that promoter mismethylation is not a main determinant of hybrid misexpression in Ficedula flycatchers. Using allele-specific methylation estimates in hybrids, we also determine the genome-wide contribution of cis- and trans effects in DNA methylation differentiation. These distinct mechanisms are roughly balanced in all tissues except the brain, where trans differences predominate. CONCLUSIONS Overall, this study provides insight on the regulatory and evolutionary impact of DNA methylation in songbirds.
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Affiliation(s)
- Jesper Boman
- Department of Ecology and Genetics (IEG), Division of Evolutionary Biology, Uppsala University, Norbyvägen 18D, Uppsala, SE-752 36, Sweden.
| | - Anna Qvarnström
- Department of Ecology and Genetics (IEG), Division of Animal Ecology, Uppsala University, Norbyvägen 18D, Uppsala, SE-752 36, Sweden
| | - Carina F Mugal
- Department of Ecology and Genetics (IEG), Division of Evolutionary Biology, Uppsala University, Norbyvägen 18D, Uppsala, SE-752 36, Sweden.
- CNRS, Laboratory of Biometry and Evolutionary Biology (LBBE), UMR 5558, University of Lyon 1, Villeurbanne, France.
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6
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Dalapicolla J, Weir JT, Vilaça ST, Quaresma TF, Schneider MPC, Vasconcelos ATR, Aleixo A. Whole genomes show contrasting trends of population size changes and genomic diversity for an Amazonian endemic passerine over the late quaternary. Ecol Evol 2024; 14:e11250. [PMID: 38660467 PMCID: PMC11040105 DOI: 10.1002/ece3.11250] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2023] [Revised: 03/16/2024] [Accepted: 03/25/2024] [Indexed: 04/26/2024] Open
Abstract
The "Amazon tipping point" is a global change scenario resulting in replacement of upland terra-firme forests by large-scale "savannization" of mostly southern and eastern Amazon. Reduced rainfall accompanying the Last Glacial Maximum (LGM) has been proposed to have acted as such a tipping point in the past, with the prediction that terra-firme inhabiting species should have experienced reductions in population size as drier habitats expanded. Here, we use whole-genomes of an Amazonian endemic organism (Scale-backed antbirds - Willisornis spp.) sampled from nine populations across the region to test this historical demography scenario. Populations from southeastern Amazonia and close to the Amazon-Cerrado ecotone exhibited a wide range of demographic patterns, while most of those from northern and western Amazonia experienced uniform expansions between 400 kya and 80-60 kya, with gradual declines toward 20 kya. Southeastern populations of Willisornis were the last to diversify and showed smaller heterozygosity and higher runs of homozygosity values than western and northern populations. These patterns support historical population declines throughout the Amazon that affected more strongly lineages in the southern and eastern areas, where historical "tipping point" conditions existed due to the widespread replacement of humid forest by drier and open vegetation during the LGM.
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Affiliation(s)
- Jeronymo Dalapicolla
- Instituto Tecnológico ValeBelémParáBrazil
- Departamento de Sistemática e EcologiaUniversidade Federal da Paraíba, João PessoaParaíbaBrazil
| | - Jason T. Weir
- Department of Biological SciencesUniversity of Toronto ScarboroughTorontoOntarioCanada
- Department of Ecology and Evolutionary BiologyUniversity of TorontoTorontoOntarioCanada
- Department of Natural History, Royal Ontario MuseumTorontoOntarioCanada
| | | | | | - Maria P. C. Schneider
- Laboratório de Genômica e BiotecnologiaInstituto de Ciências Biológicas, UFPABelémBrazil
| | - Ana Tereza R. Vasconcelos
- Laboratório de BioinformáticaLaboratório Nacional de Computação Científica, PetrópolisRio de JaneiroBrazil
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7
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Bourgeois Y, Warren BH, Augiron S. The burden of anthropogenic changes and mutation load in a critically endangered harrier from the Reunion biodiversity hotspot, Circus maillardi. Mol Ecol 2024; 33:e17300. [PMID: 38372440 DOI: 10.1111/mec.17300] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2022] [Revised: 01/18/2024] [Accepted: 01/30/2024] [Indexed: 02/20/2024]
Abstract
Anthropogenic impact is causing the decline of a large proportion of species worldwide and reduces their genetic diversity. Island species typically have smaller ranges than continental species. As a consequence, island species are particularly liable to undergo population bottlenecks, giving rise to conservation challenges such as inbreeding and unmasking of deleterious genetic load. Such challenges call for more detailed assessments of the genetic make-up of threatened island populations. The Mascarene islands (Indian Ocean) present many prime examples, being unusual in having been pristine until first human arrival ~400 years ago, following which anthropogenic pressure was unusually intense. A threatened harrier (Circus maillardi) endemic to the westernmost island of the archipelago is a good example of the challenges faced by species that have declined to small population size following intense anthropogenic pressure. In this study, we use an extensive set of population genomic tools to quantify variation at near-neutral and coding loci, in order to test the historical impact of human activity on this species, and evaluate the species' (mal)adaptive potential. We observed low but significant genetic differentiation between populations on the West and North-East sides of the island, echoing observations in other endemic species. Inbreeding was significant, with a substantial fraction of samples being first or second-degree relatives. Historical effective population sizes have declined from ~3000 to 300 individuals in the past 1000 years, with a more recent drop ~100 years ago consistent with human activity. Based on our simulations and comparisons with a close relative (Circus melanoleucos), this demographic history may have allowed purging of the most deleterious variants but is unlikely to have allowed the purging of mildly deleterious variants. Our study shows how using relatively affordable methods can reveal the massive impact that human activity may have on the genetic diversity and adaptive potential of island populations, and calls for urgent action to closely monitor the reproductive success of such endemic populations, in association with genetic studies.
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Affiliation(s)
- Yann Bourgeois
- DIADE, University of Montpellier, CIRAD, IRD, Montpellier, France
- School of Biological Sciences, University of Portsmouth, Portsmouth, UK
| | - Ben H Warren
- Institut de Systématique, Evolution, Biodiversité (ISYEB), Muséum National d'Histoire Naturelle, CNRS, Sorbonne Université, EPHE, UA, Paris, France
| | - Steve Augiron
- Société d'Études Ornithologiques de La Réunion, Saint-André, France
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8
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Gabrielli M, Leroy T, Salmona J, Nabholz B, Milá B, Thébaud C. Demographic responses of oceanic island birds to local and regional ecological disruptions revealed by whole-genome sequencing. Mol Ecol 2024; 33:e17243. [PMID: 38108507 DOI: 10.1111/mec.17243] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2023] [Revised: 11/26/2023] [Accepted: 11/30/2023] [Indexed: 12/19/2023]
Abstract
Disentangling the effects of ecological disruptions operating at different spatial and temporal scales in shaping past species' demography is particularly important in the current context of rapid environmental changes driven by both local and regional factors. We argue that volcanic oceanic islands provide useful settings to study the influence of past ecological disruptions operating at local and regional scales on population demographic histories. We investigate potential drivers of past population dynamics for three closely related species of passerine birds from two volcanic oceanic islands, Reunion and Mauritius (Mascarene archipelago), with distinct volcanic history. Using ABC and PSMC inferences from complete genomes, we reconstructed the demographic history of the Reunion Grey White-eye (Zosterops borbonicus (Pennant, 1781)), the Reunion Olive White-eye (Z. olivaceus (Linnaeus, 1766)) and the Mauritius Grey White-eye (Z. mauritianus (Gmelin, 1789)) and searched for possible causes underlying similarities or differences between species living on the same or different islands. Both demographic inferences strongly support ancient and long-term expansions in all species. They also reveal different trajectories between species inhabiting different islands, but consistent demographic trajectories in species or populations from the same island. Species from Reunion appear to have experienced synchronous reductions in population size during the Last Glacial Maximum, a trend not seen in the Mauritian species. Overall, this study suggests that local events may have played a role in shaping population trajectories of these island species. It also highlights the potential of our conceptual framework to disentangle the effects of local and regional drivers on past species' demography and long-term population processes.
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Affiliation(s)
- Maëva Gabrielli
- Laboratoire Évolution et Diversité Biologique (EDB), UMR 5174 (Université Paul Sabatier, CNRS, IRD), Toulouse, France
- Department of Life Sciences and Biotechnology, University of Ferrara, Ferrara, Italy
| | - Thibault Leroy
- GenPhySE, INRAE, INP, ENVT, Université de Toulouse, Castanet-Tolosan, France
| | - Jordi Salmona
- Laboratoire Évolution et Diversité Biologique (EDB), UMR 5174 (Université Paul Sabatier, CNRS, IRD), Toulouse, France
| | - Benoit Nabholz
- Institut des Sciences de l'Evolution de Montpellier, UMR 5554 (Université de Montpellier, CNRS, IRD, EPHE), Montpellier, France
| | - Borja Milá
- National Museum of Natural Sciences, Spanish National Research Council (CSIC), Madrid, Spain
| | - Christophe Thébaud
- Laboratoire Évolution et Diversité Biologique (EDB), UMR 5174 (Université Paul Sabatier, CNRS, IRD), Toulouse, France
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9
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Chase MA, Vilcot M, Mugal CF. The role of recombination dynamics in shaping signatures of direct and indirect selection across the Ficedula flycatcher genome †. Proc Biol Sci 2024; 291:20232382. [PMID: 38228173 DOI: 10.1098/rspb.2023.2382] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2022] [Accepted: 12/14/2023] [Indexed: 01/18/2024] Open
Abstract
Recombination is a central evolutionary process that reshuffles combinations of alleles along chromosomes, and consequently is expected to influence the efficacy of direct selection via Hill-Robertson interference. Additionally, the indirect effects of selection on neutral genetic diversity are expected to show a negative relationship with recombination rate, as background selection and genetic hitchhiking are stronger when recombination rate is low. However, owing to the limited availability of recombination rate estimates across divergent species, the impact of evolutionary changes in recombination rate on genomic signatures of selection remains largely unexplored. To address this question, we estimate recombination rate in two Ficedula flycatcher species, the taiga flycatcher (Ficedula albicilla) and collared flycatcher (Ficedula albicollis). We show that recombination rate is strongly correlated with signatures of indirect selection, and that evolutionary changes in recombination rate between species have observable impacts on this relationship. Conversely, signatures of direct selection on coding sequences show little to no relationship with recombination rate, even when restricted to genes where recombination rate is conserved between species. Thus, using measures of indirect and direct selection that bridge micro- and macro-evolutionary timescales, we demonstrate that the role of recombination rate and its dynamics varies for different signatures of selection.
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Affiliation(s)
- Madeline A Chase
- Department of Ecology and Genetics, Uppsala University, 75236 Uppsala, Sweden
- Swiss Ornithological Institute, 6204 Sempach, Switzerland
| | - Maurine Vilcot
- Department of Ecology and Genetics, Uppsala University, 75236 Uppsala, Sweden
- CEFE, University of Montpellier, CNRS, EPHE, IRD, 34293 Montpellier 5, France
| | - Carina F Mugal
- Department of Ecology and Genetics, Uppsala University, 75236 Uppsala, Sweden
- Laboratory of Biometry and Evolutionary Biology, University of Lyon 1, CNRS UMR 5558, 69622 Villeurbanne cedex, France
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10
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Mohd Shaha FR, Liew PL, Qamaruz Zaman F, Nulit R, Barin J, Rolland J, Yong HY, Boon SH. Genotyping by sequencing for the construction of oil palm ( Elaeis guineensis Jacq.) genetic linkage map and mapping of yield related quantitative trait loci. PeerJ 2024; 12:e16570. [PMID: 38313025 PMCID: PMC10836210 DOI: 10.7717/peerj.16570] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2022] [Accepted: 11/13/2023] [Indexed: 02/06/2024] Open
Abstract
Background Oil palm (Elaeis guineensis Jacq.) is one of the major oil-producing crops. Improving the quality and increasing the production yield of oil palm have been the primary focuses of both conventional and modern breeding approaches. However, the conventional breeding approach for oil palm is very challenging due to its longevity, which results in a long breeding cycle. Thus, the establishment of marker assisted selection (MAS) for oil palm breeding programs would speed up the breeding pipeline by generating new oil palm varieties that possess high commercial traits. With the decreasing cost of sequencing, Genotyping-by-sequencing (GBS) is currently feasible to many researchers and it provides a platform to accelerate the discovery of single nucleotide polymorphism (SNP) as well as insertion and deletion (InDel) markers for the construction of a genetic linkage map. A genetic linkage map facilitates the identification of significant DNA regions associated with the trait of interest via quantitative trait loci (QTL) analysis. Methods A mapping population of 112 F1 individuals from a cross of Deli dura and Serdang pisifera was used in this study. GBS libraries were constructed using the double digestion method with HindIII and TaqI enzymes. Reduced representation libraries (RRL) of 112 F1 progeny and their parents were sequenced and the reads were mapped against the E. guineensis reference genome. To construct the oil palm genetic linkage map, informative SNP and InDel markers were used to discover significant DNA regions associated with the traits of interest. The nine traits of interest in this study were fresh fruit bunch (FFB) yield, oil yield (OY), oil to bunch ratio (O/B), oil to dry mesocarp ratio (O/DM) ratio, oil to wet mesocarp ratio (O/WM), mesocarp to fruit ratio (M/F), kernel to fruit ratio (K/F), shell to fruit ratio (S/F), and fruit to bunch ratio (F/B). Results A total of 2.5 million SNP and 153,547 InDel markers were identified. However, only a subset of 5,278 markers comprising of 4,838 SNPs and 440 InDels were informative for the construction of a genetic linkage map. Sixteen linkage groups were produced, spanning 2,737.6 cM for the maternal map and 4,571.6 cM for the paternal map, with average marker densities of one marker per 2.9 cM and one per 2.0 cM respectively, were produced. A QTL analysis was performed on nine traits; however, only QTL regions linked to M/F, K/F and S/F were declared to be significant. Of those QTLs were detected: two for M/F, four for K/F and one for S/F. These QTLs explained 18.1-25.6% of the phenotypic variance and were located near putative genes, such as casein kinase II and the zinc finger CCCH domain, which are involved in seed germination and growth. The identified QTL regions for M/F, K/F and S/F from this study could be applied in an oil palm breeding program and used to screen palms with desired traits via marker assisted selection (MAS).
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Affiliation(s)
- Fakhrur Razi Mohd Shaha
- ACGT Sdn. Bhd. & Laboratories, Bukit Jalil, Kuala Lumpur, Malaysia
- Department of Biology, Faculty of Science, Universiti Putra Malaysia, Serdang, Selangor, Malaysia
| | - Pui Ling Liew
- ACGT Sdn. Bhd. & Laboratories, Bukit Jalil, Kuala Lumpur, Malaysia
| | - Faridah Qamaruz Zaman
- Department of Biology, Faculty of Science, Universiti Putra Malaysia, Serdang, Selangor, Malaysia
| | - Rosimah Nulit
- Department of Biology, Faculty of Science, Universiti Putra Malaysia, Serdang, Selangor, Malaysia
| | - Jakim Barin
- Wisma Pertanian Sabah, Department of Agriculture Sabah, Kota Kinabalu, Sabah, Malaysia
| | - Justina Rolland
- Wisma Pertanian Sabah, Department of Agriculture Sabah, Kota Kinabalu, Sabah, Malaysia
| | - Hui Yee Yong
- ACGT Sdn. Bhd. & Laboratories, Bukit Jalil, Kuala Lumpur, Malaysia
| | - Soo Heong Boon
- ACGT Sdn. Bhd. & Laboratories, Bukit Jalil, Kuala Lumpur, Malaysia
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11
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Chase MA, Vilcot M, Mugal CF. Evidence that genetic drift not adaptation drives fast-Z and large-Z effects in Ficedula flycatchers. Mol Ecol 2024:e17262. [PMID: 38193599 DOI: 10.1111/mec.17262] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2023] [Revised: 12/01/2023] [Accepted: 12/22/2023] [Indexed: 01/10/2024]
Abstract
The sex chromosomes have been hypothesized to play a key role in driving adaptation and speciation across many taxa. The reason for this is thought to be the hemizygosity of the heteromorphic part of sex chromosomes in the heterogametic sex, which exposes recessive mutations to natural and sexual selection. The exposure of recessive beneficial mutations increases their rate of fixation on the sex chromosomes, which results in a faster rate of evolution. In addition, genetic incompatibilities between sex-linked loci are exposed faster in the genomic background of hybrids of divergent lineages, which makes sex chromosomes contribute disproportionately to reproductive isolation. However, in birds, which show a Z/W sex determination system, the role of adaptation versus genetic drift as the driving force of the faster differentiation of the Z chromosome (fast-Z effect) and the disproportionate role of the Z chromosome in reproductive isolation (large-Z effect) are still debated. Here, we address this debate in the bird genus Ficedula flycatchers based on population-level whole-genome sequencing data of six species. Our analysis provides evidence for both faster lineage sorting and reduced gene flow on the Z chromosome than the autosomes. However, these patterns appear to be driven primarily by the increased role of genetic drift on the Z chromosome, rather than an increased rate of adaptive evolution. Genomic scans of selective sweeps and fixed differences in fact suggest a reduced action of positive selection on the Z chromosome.
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Affiliation(s)
- Madeline A Chase
- Department of Ecology and Genetics, Uppsala University, Uppsala, Sweden
- Swiss Ornithological Institute, Sempach, Switzerland
| | - Maurine Vilcot
- Department of Ecology and Genetics, Uppsala University, Uppsala, Sweden
- CEFE, University of Montpellier, CNRS, EPHE, IRD, Montpellier, France
| | - Carina F Mugal
- Department of Ecology and Genetics, Uppsala University, Uppsala, Sweden
- Laboratory of Biometry and Evolutionary Biology, University of Lyon 1, CNRS UMR 5558, Villeurbanne, France
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12
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Bascón-Cardozo K, Bours A, Manthey G, Durieux G, Dutheil JY, Pruisscher P, Odenthal-Hesse L, Liedvogel M. Fine-Scale Map Reveals Highly Variable Recombination Rates Associated with Genomic Features in the Eurasian Blackcap. Genome Biol Evol 2024; 16:evad233. [PMID: 38198800 PMCID: PMC10781513 DOI: 10.1093/gbe/evad233] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 12/12/2023] [Indexed: 01/12/2024] Open
Abstract
Recombination is responsible for breaking up haplotypes, influencing genetic variability, and the efficacy of selection. Bird genomes lack the protein PR domain-containing protein 9, a key determinant of recombination dynamics in most metazoans. Historical recombination maps in birds show an apparent stasis in positioning recombination events. This highly conserved recombination pattern over long timescales may constrain the evolution of recombination in birds. At the same time, extensive variation in recombination rate is observed across the genome and between different species of birds. Here, we characterize the fine-scale historical recombination map of an iconic migratory songbird, the Eurasian blackcap (Sylvia atricapilla), using a linkage disequilibrium-based approach that accounts for population demography. Our results reveal variable recombination rates among and within chromosomes, which associate positively with nucleotide diversity and GC content and negatively with chromosome size. Recombination rates increased significantly at regulatory regions but not necessarily at gene bodies. CpG islands are associated strongly with recombination rates, though their specific position and local DNA methylation patterns likely influence this relationship. The association with retrotransposons varied according to specific family and location. Our results also provide evidence of heterogeneous intrachromosomal conservation of recombination maps between the blackcap and its closest sister taxon, the garden warbler. These findings highlight the considerable variability of recombination rates at different scales and the role of specific genomic features in shaping this variation. This study opens the possibility of further investigating the impact of recombination on specific population-genomic features.
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Affiliation(s)
- Karen Bascón-Cardozo
- MPRG Behavioural Genomics, Max Planck Institute for Evolutionary Biology, Plön 24306, Germany
| | - Andrea Bours
- MPRG Behavioural Genomics, Max Planck Institute for Evolutionary Biology, Plön 24306, Germany
| | - Georg Manthey
- Institute of Avian Research “Vogelwarte Helgoland”, Wilhelmshaven 26386, Germany
| | - Gillian Durieux
- MPRG Behavioural Genomics, Max Planck Institute for Evolutionary Biology, Plön 24306, Germany
| | - Julien Y Dutheil
- Department for Theoretical Biology, Max Planck Institute for Evolutionary Biology, Plön 24306, Germany
| | - Peter Pruisscher
- MPRG Behavioural Genomics, Max Planck Institute for Evolutionary Biology, Plön 24306, Germany
- Department of Zoology, Stockholm University, Stockholm SE-106 91, Sweden
| | - Linda Odenthal-Hesse
- Department Evolutionary Genetics, Max Planck Institute for Evolutionary Biology, Plön 24306, Germany
| | - Miriam Liedvogel
- MPRG Behavioural Genomics, Max Planck Institute for Evolutionary Biology, Plön 24306, Germany
- Institute of Avian Research “Vogelwarte Helgoland”, Wilhelmshaven 26386, Germany
- Department of Biology and Environmental Sciences, Carl von Ossietzky University of Oldenburg, Oldenburg 26129, Germany
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13
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Thom G, Moreira LR, Batista R, Gehara M, Aleixo A, Smith BT. Genomic Architecture Predicts Tree Topology, Population Structuring, and Demographic History in Amazonian Birds. Genome Biol Evol 2024; 16:evae002. [PMID: 38236173 PMCID: PMC10823491 DOI: 10.1093/gbe/evae002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2023] [Revised: 10/26/2023] [Accepted: 12/12/2023] [Indexed: 01/19/2024] Open
Abstract
Geographic barriers are frequently invoked to explain genetic structuring across the landscape. However, inferences on the spatial and temporal origins of population variation have been largely limited to evolutionary neutral models, ignoring the potential role of natural selection and intrinsic genomic processes known as genomic architecture in producing heterogeneity in differentiation across the genome. To test how variation in genomic characteristics (e.g. recombination rate) impacts our ability to reconstruct general patterns of differentiation between species that cooccur across geographic barriers, we sequenced the whole genomes of multiple bird populations that are distributed across rivers in southeastern Amazonia. We found that phylogenetic relationships within species and demographic parameters varied across the genome in predictable ways. Genetic diversity was positively associated with recombination rate and negatively associated with species tree support. Gene flow was less pervasive in genomic regions of low recombination, making these windows more likely to retain patterns of population structuring that matched the species tree. We further found that approximately a third of the genome showed evidence of selective sweeps and linked selection, skewing genome-wide estimates of effective population sizes and gene flow between populations toward lower values. In sum, we showed that the effects of intrinsic genomic characteristics and selection can be disentangled from neutral processes to elucidate spatial patterns of population differentiation.
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Affiliation(s)
- Gregory Thom
- Department of Ornithology, American Museum of Natural History, New York, NY, USA
- Museum of Natural Science, Louisiana State University, Baton Rouge, LA, USA
- Department of Biological Sciences, Louisiana State University, Baton Rouge, LA, USA
| | - Lucas Rocha Moreira
- Program in Bioinformatics and Integrative Biology, University of Massachusetts Chan Medical School, Worcester, MA, USA
- Department of Vertebrate Genomics, Broad Institute of MIT and Harvard, Cambridge, MA, USA
| | - Romina Batista
- Programa de Coleções Biológicas, Instituto Nacional de Pesquisas da Amazônia, Manaus, Brazil
- School of Science, Engineering and Environment, University of Salford, Manchester, UK
| | - Marcelo Gehara
- Department of Earth and Environmental Sciences, Rutgers University, Newark, NJ, USA
| | - Alexandre Aleixo
- Finnish Museum of Natural History, University of Helsinki, Helsinki, Finland
- Department of Environmental Genomics, Instituto Tecnológico Vale, Belém, Brazil
| | - Brian Tilston Smith
- Department of Ornithology, American Museum of Natural History, New York, NY, USA
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14
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Hofmeister NR, Stuart KC, Warren WC, Werner SJ, Bateson M, Ball GF, Buchanan KL, Burt DW, Cardilini APA, Cassey P, De Meyer T, George J, Meddle SL, Rowland HM, Sherman CDH, Sherwin WB, Vanden Berghe W, Rollins LA, Clayton DF. Concurrent invasions of European starlings in Australia and North America reveal population-specific differentiation in shared genomic regions. Mol Ecol 2023. [PMID: 37933429 DOI: 10.1111/mec.17195] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2022] [Revised: 09/22/2023] [Accepted: 10/23/2023] [Indexed: 11/08/2023]
Abstract
A species' success during the invasion of new areas hinges on an interplay between the demographic processes common to invasions and the specific ecological context of the novel environment. Evolutionary genetic studies of invasive species can investigate how genetic bottlenecks and ecological conditions shape genetic variation in invasions, and our study pairs two invasive populations that are hypothesized to be from the same source population to compare how each population evolved during and after introduction. Invasive European starlings (Sturnus vulgaris) established populations in both Australia and North America in the 19th century. Here, we compare whole-genome sequences among native and independently introduced European starling populations to determine how demographic processes interact with rapid evolution to generate similar genetic patterns in these recent and replicated invasions. Demographic models indicate that both invasive populations experienced genetic bottlenecks as expected based on invasion history, and we find that specific genomic regions have differentiated even on this short evolutionary timescale. Despite genetic bottlenecks, we suggest that genetic drift alone cannot explain differentiation in at least two of these regions. The demographic boom intrinsic to many invasions as well as potential inversions may have led to high population-specific differentiation, although the patterns of genetic variation are also consistent with the hypothesis that this infamous and highly mobile invader adapted to novel selection (e.g., extrinsic factors). We use targeted sampling of replicated invasions to identify and evaluate support for multiple, interacting evolutionary mechanisms that lead to differentiation during the invasion process.
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Affiliation(s)
- Natalie R Hofmeister
- Department of Ecology and Evolutionary Biology, Cornell University, Ithaca, New York, USA
- Fuller Evolutionary Biology Program, Cornell Lab of Ornithology, Ithaca, New York, USA
| | - Katarina C Stuart
- School of Biological, Earth and Environmental Sciences, Evolution & Ecology Research Centre, UNSW Sydney, Sydney, New South Wales, Australia
| | - Wesley C Warren
- Department of Animal Sciences and Surgery, Institute for Data Science and Informatics, University of Missouri, Columbia, Missouri, USA
| | - Scott J Werner
- United States Department of Agriculture, Animal and Plant Health Inspection Service, Wildlife Services, National Wildlife Research Center, Fort Collins, Colorado, USA
| | - Melissa Bateson
- Biosciences Institute, Newcastle University, Newcastle upon Tyne, UK
| | - Gregory F Ball
- Department of Psychology, University of Maryland, College Park, Maryland, USA
| | | | - David W Burt
- Office of the Deputy Vice-Chancellor (Research and Innovation), The University of Queensland, Brisbane, Queensland, Australia
- The Roslin Institute, The Royal (Dick) School of Veterinary Studies, The University of Edinburgh, Midlothian, UK
| | - Adam P A Cardilini
- School of Life and Environmental Sciences, Deakin University, Waurn Ponds, Victoria, Australia
| | - Phillip Cassey
- Invasion Science & Wildlife Ecology Lab, University of Adelaide, Adelaide, South Australia, Australia
| | - Tim De Meyer
- Department of Data Analysis and Mathematical Modelling, Ghent University, Ghent, Belgium
| | - Julia George
- Department of Biological Sciences, Clemson University, Clemson, South Carolina, USA
| | - Simone L Meddle
- The Roslin Institute, The Royal (Dick) School of Veterinary Studies, The University of Edinburgh, Midlothian, UK
| | - Hannah M Rowland
- Max Planck Institute for Chemical Ecology, Jena, Germany
- Department of Zoology, University of Cambridge, Cambridge, UK
| | - Craig D H Sherman
- The Roslin Institute, The Royal (Dick) School of Veterinary Studies, The University of Edinburgh, Midlothian, UK
| | - William B Sherwin
- School of Biological, Earth and Environmental Sciences, Evolution & Ecology Research Centre, UNSW Sydney, Sydney, New South Wales, Australia
| | - Wim Vanden Berghe
- Department of Biomedical Sciences, University Antwerp, Antwerp, Belgium
| | - Lee Ann Rollins
- School of Biological, Earth and Environmental Sciences, Evolution & Ecology Research Centre, UNSW Sydney, Sydney, New South Wales, Australia
| | - David F Clayton
- Department of Genetics & Biochemistry, Clemson University, Clemson, South Carolina, USA
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15
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Kersten O, Star B, Krabberød AK, Atmore LM, Tørresen OK, Anker-Nilssen T, Descamps S, Strøm H, Johansson US, Sweet PR, Jakobsen KS, Boessenkool S. Hybridization of Atlantic puffins in the Arctic coincides with 20th-century climate change. SCIENCE ADVANCES 2023; 9:eadh1407. [PMID: 37801495 PMCID: PMC10558128 DOI: 10.1126/sciadv.adh1407] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/17/2023] [Accepted: 09/06/2023] [Indexed: 10/08/2023]
Abstract
The Arctic is experiencing the fastest rates of global warming, leading to shifts in the distribution of its biota and increasing the potential for hybridization. However, genomic evidence of recent hybridization events in the Arctic remains unexpectedly rare. Here, we use whole-genome sequencing of contemporary and 122-year-old historical specimens to investigate the origin of an Arctic hybrid population of Atlantic puffins (Fratercula arctica) on Bjørnøya, Norway. We show that the hybridization between the High Arctic, large-bodied subspecies F. a. naumanni and the temperate, smaller-sized subspecies F. a. arctica began as recently as six generations ago due to an unexpected southward range expansion of F. a. naumanni. Moreover, we find a significant temporal loss of genetic diversity across Arctic and temperate puffin populations. Our observations provide compelling genomic evidence of the impacts of recent distributional shifts and loss of diversity in Arctic communities during the 20th century.
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Affiliation(s)
- Oliver Kersten
- Centre for Ecological and Evolutionary Synthesis (CEES), Department of Biosciences, University of Oslo, Oslo, Norway
| | - Bastiaan Star
- Centre for Ecological and Evolutionary Synthesis (CEES), Department of Biosciences, University of Oslo, Oslo, Norway
| | - Anders K. Krabberød
- Section for Genetics and Evolutionary Biology (Evogene), Department of Biosciences, University of Oslo, Oslo, Norway
| | - Lane M. Atmore
- Centre for Ecological and Evolutionary Synthesis (CEES), Department of Biosciences, University of Oslo, Oslo, Norway
| | - Ole K. Tørresen
- Centre for Ecological and Evolutionary Synthesis (CEES), Department of Biosciences, University of Oslo, Oslo, Norway
| | | | | | - Hallvard Strøm
- Norwegian Polar Institute, Fram Centre, Langnes, Tromsø, Norway
| | | | - Paul R. Sweet
- American Museum of Natural History, New York, NY, USA
| | - Kjetill S. Jakobsen
- Centre for Ecological and Evolutionary Synthesis (CEES), Department of Biosciences, University of Oslo, Oslo, Norway
| | - Sanne Boessenkool
- Centre for Ecological and Evolutionary Synthesis (CEES), Department of Biosciences, University of Oslo, Oslo, Norway
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16
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Soni V, Johri P, Jensen JD. Evaluating power to detect recurrent selective sweeps under increasingly realistic evolutionary null models. Evolution 2023; 77:2113-2127. [PMID: 37395482 PMCID: PMC10547124 DOI: 10.1093/evolut/qpad120] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2023] [Revised: 06/15/2023] [Accepted: 06/30/2023] [Indexed: 07/04/2023]
Abstract
The detection of selective sweeps from population genomic data often relies on the premise that the beneficial mutations in question have fixed very near the sampling time. As it has been previously shown that the power to detect a selective sweep is strongly dependent on the time since fixation as well as the strength of selection, it is naturally the case that strong, recent sweeps leave the strongest signatures. However, the biological reality is that beneficial mutations enter populations at a rate, one that partially determines the mean wait time between sweep events and hence their age distribution. An important question thus remains about the power to detect recurrent selective sweeps when they are modeled by a realistic mutation rate and as part of a realistic distribution of fitness effects, as opposed to a single, recent, isolated event on a purely neutral background as is more commonly modeled. Here we use forward-in-time simulations to study the performance of commonly used sweep statistics, within the context of more realistic evolutionary baseline models incorporating purifying and background selection, population size change, and mutation and recombination rate heterogeneity. Results demonstrate the important interplay of these processes, necessitating caution when interpreting selection scans; specifically, false-positive rates are in excess of true-positive across much of the evaluated parameter space, and selective sweeps are often undetectable unless the strength of selection is exceptionally strong.
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Affiliation(s)
- Vivak Soni
- School of Life Sciences, Arizona State University, Tempe, AZ, United States
| | - Parul Johri
- School of Life Sciences, Arizona State University, Tempe, AZ, United States
| | - Jeffrey D Jensen
- School of Life Sciences, Arizona State University, Tempe, AZ, United States
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17
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Catalán A, Merondun J, Knief U, Wolf JBW. Chromatin accessibility, not 5mC methylation covaries with partial dosage compensation in crows. PLoS Genet 2023; 19:e1010901. [PMID: 37747941 PMCID: PMC10575545 DOI: 10.1371/journal.pgen.1010901] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2023] [Revised: 10/13/2023] [Accepted: 08/07/2023] [Indexed: 09/27/2023] Open
Abstract
The evolution of genetic sex determination is often accompanied by degradation of the sex-limited chromosome. Male heterogametic systems have evolved convergent, epigenetic mechanisms restoring the resulting imbalance in gene dosage between diploid autosomes (AA) and the hemizygous sex chromosome (X). Female heterogametic systems (AAf Zf, AAm ZZm) tend to only show partial dosage compensation (0.5 < Zf:AAf < 1) and dosage balance (0.5
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Affiliation(s)
- Ana Catalán
- Department of Evolutionary Biology, Evolutionary Biology Centre (EBC), Uppsala University, Uppsala, Sweden
- Division of Evolutionary Biology, LMU Munich, Planegg-Martinsried, Germany
| | - Justin Merondun
- Division of Evolutionary Biology, LMU Munich, Planegg-Martinsried, Germany
| | - Ulrich Knief
- Division of Evolutionary Biology, LMU Munich, Planegg-Martinsried, Germany
- Evolutionary Biology & Ecology,Faculty of Biology, University of Freiburg, Freiburg, Germany
| | - Jochen B. W. Wolf
- Department of Evolutionary Biology, Evolutionary Biology Centre (EBC), Uppsala University, Uppsala, Sweden
- Division of Evolutionary Biology, LMU Munich, Planegg-Martinsried, Germany
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18
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Schlebusch SA, Rídl J, Poignet M, Ruiz-Ruano FJ, Reif J, Pajer P, Pačes J, Albrecht T, Suh A, Reifová R. Rapid gene content turnover on the germline-restricted chromosome in songbirds. Nat Commun 2023; 14:4579. [PMID: 37516764 PMCID: PMC10387091 DOI: 10.1038/s41467-023-40308-8] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2022] [Accepted: 07/20/2023] [Indexed: 07/31/2023] Open
Abstract
The germline-restricted chromosome (GRC) of songbirds represents a taxonomically widespread example of programmed DNA elimination. Despite its apparent indispensability, we still know very little about the GRC's genetic composition, function, and evolutionary significance. Here we assemble the GRC in two closely related species, the common and thrush nightingale. In total we identify 192 genes across the two GRCs, with many of them present in multiple copies. Interestingly, the GRC appears to be under little selective pressure, with the genetic content differing dramatically between the two species and many GRC genes appearing to be pseudogenized fragments. Only one gene, cpeb1, has a complete coding region in all examined individuals of the two species and shows no copy number variation. The acquisition of this gene by the GRC corresponds with the earliest estimates of the GRC origin, making it a good candidate for the functional indispensability of the GRC in songbirds.
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Affiliation(s)
- Stephen A Schlebusch
- Department of Zoology, Faculty of Science, Charles University, Prague, Czech Republic.
| | - Jakub Rídl
- Department of Zoology, Faculty of Science, Charles University, Prague, Czech Republic
- Institute of Molecular Genetics, Czech Academy of Sciences, Prague, Czech Republic
| | - Manon Poignet
- Department of Zoology, Faculty of Science, Charles University, Prague, Czech Republic
| | - Francisco J Ruiz-Ruano
- School of Biological Sciences, University of East Anglia, Norwich, UK
- Department of Organismal Biology - Systematic Biology, Evolutionary Biology Centre, Science for Life Laboratory, Uppsala University, Norbyvägen 18D, 752 36, Uppsala, Sweden
- Institute of Evolutionary Biology and Ecology, University of Bonn, An der Immenburg 1, 53121, Bonn, Germany
- Centre for Molecular Biodiversity Research, Leibniz Institute for the Analysis of Biodiversity Change, Adenauerallee 127, 53113, Bonn, Germany
| | - Jiří Reif
- Institute for Environmental Studies, Faculty of Science, Charles University, Prague, Czech Republic
- Department of Zoology, Faculty of Science, Palacky University, Olomouc, Czech Republic
| | - Petr Pajer
- Military Health Institute, Military Medical Agency, Tychonova 1, 160 01, Prague 6, San Antonio, Czech Republic
| | - Jan Pačes
- Institute of Molecular Genetics, Czech Academy of Sciences, Prague, Czech Republic
| | - Tomáš Albrecht
- Department of Zoology, Faculty of Science, Charles University, Prague, Czech Republic
- Institute of Vertebrate Biology, Czech Academy of Sciences, Brno, Czech Republic
| | - Alexander Suh
- School of Biological Sciences, University of East Anglia, Norwich, UK
- Department of Organismal Biology - Systematic Biology, Evolutionary Biology Centre, Science for Life Laboratory, Uppsala University, Norbyvägen 18D, 752 36, Uppsala, Sweden
- Centre for Molecular Biodiversity Research, Leibniz Institute for the Analysis of Biodiversity Change, Adenauerallee 127, 53113, Bonn, Germany
| | - Radka Reifová
- Department of Zoology, Faculty of Science, Charles University, Prague, Czech Republic.
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19
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Soni V, Johri P, Jensen JD. Evaluating power to detect recurrent selective sweeps under increasingly realistic evolutionary null models. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.06.15.545166. [PMID: 37398347 PMCID: PMC10312679 DOI: 10.1101/2023.06.15.545166] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/04/2023]
Abstract
The detection of selective sweeps from population genomic data often relies on the premise that the beneficial mutations in question have fixed very near the sampling time. As it has been previously shown that the power to detect a selective sweep is strongly dependent on the time since fixation as well as the strength of selection, it is naturally the case that strong, recent sweeps leave the strongest signatures. However, the biological reality is that beneficial mutations enter populations at a rate, one that partially determines the mean wait time between sweep events and hence their age distribution. An important question thus remains about the power to detect recurrent selective sweeps when they are modelled by a realistic mutation rate and as part of a realistic distribution of fitness effects (DFE), as opposed to a single, recent, isolated event on a purely neutral background as is more commonly modelled. Here we use forward-in-time simulations to study the performance of commonly used sweep statistics, within the context of more realistic evolutionary baseline models incorporating purifying and background selection, population size change, and mutation and recombination rate heterogeneity. Results demonstrate the important interplay of these processes, necessitating caution when interpreting selection scans; specifically, false positive rates are in excess of true positive across much of the evaluated parameter space, and selective sweeps are often undetectable unless the strength of selection is exceptionally strong. Teaser Text Outlier-based genomic scans have proven a popular approach for identifying loci that have potentially experienced recent positive selection. However, it has previously been shown that an evolutionarily appropriate baseline model that incorporates non-equilibrium population histories, purifying and background selection, and variation in mutation and recombination rates is necessary to reduce often extreme false positive rates when performing genomic scans. Here we evaluate the power to detect recurrent selective sweeps using common SFS-based and haplotype-based methods under these increasingly realistic models. We find that while these appropriate evolutionary baselines are essential to reduce false positive rates, the power to accurately detect recurrent selective sweeps is generally low across much of the biologically relevant parameter space.
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Affiliation(s)
- Vivak Soni
- School of Life Sciences, Arizona State University, Tempe, AZ, USA
| | - Parul Johri
- School of Life Sciences, Arizona State University, Tempe, AZ, USA
- Present address: Department of Biology, Department of Genetics, University of North Carolina, Chapel Hill, NC, USA
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20
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Hewett AM, Stoffel MA, Peters L, Johnston SE, Pemberton JM. Selection, recombination and population history effects on runs of homozygosity (ROH) in wild red deer (Cervus elaphus). Heredity (Edinb) 2023; 130:242-250. [PMID: 36801920 PMCID: PMC10076382 DOI: 10.1038/s41437-023-00602-z] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2022] [Revised: 02/07/2023] [Accepted: 02/07/2023] [Indexed: 02/19/2023] Open
Abstract
The distribution of runs of homozygosity (ROH) may be shaped by a number of interacting processes such as selection, recombination and population history, but little is known about the importance of these mechanisms in shaping ROH in wild populations. We combined an empirical dataset of >3000 red deer genotyped at >35,000 genome-wide autosomal SNPs and evolutionary simulations to investigate the influence of each of these factors on ROH. We assessed ROH in a focal and comparison population to investigate the effect of population history. We investigated the role of recombination using both a physical map and a genetic linkage map to search for ROH. We found differences in ROH distribution between both populations and map types indicating that population history and local recombination rate have an effect on ROH. Finally, we ran forward genetic simulations with varying population histories, recombination rates and levels of selection, allowing us to further interpret our empirical data. These simulations showed that population history has a greater effect on ROH distribution than either recombination or selection. We further show that selection can cause genomic regions where ROH is common, only when the effective population size (Ne) is large or selection is particularly strong. In populations having undergone a population bottleneck, genetic drift can outweigh the effect of selection. Overall, we conclude that in this population, genetic drift resulting from a historical population bottleneck is most likely to have resulted in the observed ROH distribution, with selection possibly playing a minor role.
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Affiliation(s)
- Anna M Hewett
- Institute of Ecology and Evolution, School of Biological Sciences, University of Edinburgh, Edinburgh, EH9 3FL, UK.
| | - Martin A Stoffel
- Institute of Ecology and Evolution, School of Biological Sciences, University of Edinburgh, Edinburgh, EH9 3FL, UK
| | - Lucy Peters
- Institute of Ecology and Evolution, School of Biological Sciences, University of Edinburgh, Edinburgh, EH9 3FL, UK
- GenPhySE, Université de Toulouse, INRAE, ENVT, 31326, Castanet-Tolosan, France
| | - Susan E Johnston
- Institute of Ecology and Evolution, School of Biological Sciences, University of Edinburgh, Edinburgh, EH9 3FL, UK
| | - Josephine M Pemberton
- Institute of Ecology and Evolution, School of Biological Sciences, University of Edinburgh, Edinburgh, EH9 3FL, UK
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21
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Lundberg M, Mackintosh A, Petri A, Bensch S. Inversions maintain differences between migratory phenotypes of a songbird. Nat Commun 2023; 14:452. [PMID: 36707538 PMCID: PMC9883250 DOI: 10.1038/s41467-023-36167-y] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2021] [Accepted: 01/18/2023] [Indexed: 01/28/2023] Open
Abstract
Structural rearrangements have been shown to be important in local adaptation and speciation, but have been difficult to reliably identify and characterize in non-model species. Here we combine long reads, linked reads and optical mapping to characterize three divergent chromosome regions in the willow warbler Phylloscopus trochilus, of which two are associated with differences in migration and one with an environmental gradient. We show that there are inversions (0.4-13 Mb) in each of the regions and that the divergence times between inverted and non-inverted haplotypes are similar across the regions (~1.2 Myrs), which is compatible with a scenario where inversions arose in either of two allopatric populations that subsequently hybridized. The improved genomes allow us to detect additional functional differences in the divergent regions, providing candidate genes for migration and adaptations to environmental gradients.
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Affiliation(s)
- Max Lundberg
- Department of Biology, Lund University, Lund, Sweden.
| | | | - Anna Petri
- Science for Life Laboratory, Uppsala Genome Center, Uppsala University, Uppsala, Sweden
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22
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Moreira LR, Klicka J, Smith BT. Demography and linked selection interact to shape the genomic landscape of codistributed woodpeckers during the Ice Age. Mol Ecol 2023; 32:1739-1759. [PMID: 36617622 DOI: 10.1111/mec.16841] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2022] [Revised: 12/13/2022] [Accepted: 12/20/2022] [Indexed: 01/10/2023]
Abstract
The influence of genetic drift on population dynamics during Pleistocene glacial cycles is well understood, but the role of selection in shaping patterns of genomic variation during these events is less explored. We resequenced whole genomes to investigate how demography and natural selection interact to generate the genomic landscapes of Downy and Hairy Woodpecker, species codistributed in previously glaciated North America. First, we explored the spatial and temporal patterns of genomic diversity produced by neutral evolution. Next, we tested (i) whether levels of nucleotide diversity along the genome are correlated with intrinsic genomic properties, such as recombination rate and gene density, and (ii) whether different demographic trajectories impacted the efficacy of selection. Our results revealed cycles of bottleneck and expansion, and genetic structure associated with glacial refugia. Nucleotide diversity varied widely along the genome, but this variation was highly correlated between the species, suggesting the presence of conserved genomic features. In both taxa, nucleotide diversity was positively correlated with recombination rate and negatively correlated with gene density, suggesting that linked selection played a role in reducing diversity. Despite strong fluctuations in effective population size, the maintenance of relatively large populations during glaciations may have facilitated selection. Under these conditions, we found evidence that the individual demographic trajectory of populations modulated linked selection, with purifying selection being more efficient in removing deleterious alleles in large populations. These results highlight that while genome-wide variation reflects the expected signature of demographic change during climatic perturbations, the interaction of multiple processes produces a predictable and highly heterogeneous genomic landscape.
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Affiliation(s)
- Lucas R Moreira
- Department of Ecology, Evolution, and Environmental Biology, Columbia University, New York, New York, USA.,Department of Ornithology, American Museum of Natural History, New York City, New York, USA.,Program in Bioinformatics and Integrative Biology, University of Massachusetts Chan Medical School, Worcester, Massachusetts, USA
| | - John Klicka
- Burke Museum of Natural History and Culture and Department of Biology, University of Washington, Seattle, Washington, USA
| | - Brian Tilston Smith
- Department of Ornithology, American Museum of Natural History, New York City, New York, USA
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23
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Griffin DK, Larkin DM, O’Connor RE, Romanov MN. Dinosaurs: Comparative Cytogenomics of Their Reptile Cousins and Avian Descendants. Animals (Basel) 2022; 13:ani13010106. [PMID: 36611715 PMCID: PMC9817885 DOI: 10.3390/ani13010106] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2022] [Revised: 12/22/2022] [Accepted: 12/23/2022] [Indexed: 12/29/2022] Open
Abstract
Reptiles known as dinosaurs pervade scientific and popular culture, while interest in their genomics has increased since the 1990s. Birds (part of the crown group Reptilia) are living theropod dinosaurs. Chromosome-level genome assemblies cannot be made from long-extinct biological material, but dinosaur genome organization can be inferred through comparative genomics of related extant species. Most reptiles apart from crocodilians have both macro- and microchromosomes; comparative genomics involving molecular cytogenetics and bioinformatics has established chromosomal relationships between many species. The capacity of dinosaurs to survive multiple extinction events is now well established, and birds now have more species in comparison with any other terrestrial vertebrate. This may be due, in part, to their karyotypic features, including a distinctive karyotype of around n = 40 (~10 macro and 30 microchromosomes). Similarity in genome organization in distantly related species suggests that the common avian ancestor had a similar karyotype to e.g., the chicken/emu/zebra finch. The close karyotypic similarity to the soft-shelled turtle (n = 33) suggests that this basic pattern was mostly established before the Testudine-Archosaur divergence, ~255 MYA. That is, dinosaurs most likely had similar karyotypes and their extensive phenotypic variation may have been mediated by increased random chromosome segregation and genetic recombination, which is inherently higher in karyotypes with more and smaller chromosomes.
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Affiliation(s)
- Darren K. Griffin
- School of Biosciences, University of Kent, Canterbury CT2 7NJ, UK
- Correspondence:
| | - Denis M. Larkin
- Department of Comparative Biomedical Sciences, Royal Veterinary College, University of London, London NW1 0TU, UK
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24
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High-Density Genetic Linkage Map of the Southern Blue-ringed Octopus (Octopodidae: Hapalochlaena maculosa). DIVERSITY 2022. [DOI: 10.3390/d14121068] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Genetic linkage maps provide a useful resource for non-model genomes and can aid in genome reassembly to form more contiguous pseudo-chromosomes. We present the first linkage map of any cephalopod, H. maculosa, composed of 47 linkage groups (LG). A total of 2166 single nucleotide polymorphisms and 2455 presence–absence variant loci were utilised by Lep-Map3 in linkage map construction. The map length spans 2016.62 cM with an average marker distance of 0.85 cM. Integration of the recent H. maculosa genome allowed 1151 scaffolds comprising 34% of the total genomic sequence to be orientated and/or placed using 1278 markers across all 47 LG. The linkage map generated provides a new perspective on HOX gene distribution in octopods. In the H. maculosa linkage map three (SCR, LOX4 and POST1) of six identified HOX genes (HOX1/LAB, SCR, LOX2, LOX4, LOX5, POST1) were located within the same LG (LG 9). The generation of a linkage map for H. maculosa has provided a valuable resource for understanding the evolution of cephalopod genomes and will provide a base for future work.
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25
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Nikolakis ZL, Schield DR, Westfall AK, Perry BW, Ivey KN, Orton RW, Hales NR, Adams RH, Meik JM, Parker JM, Smith CF, Gompert Z, Mackessy SP, Castoe TA. Evidence that genomic incompatibilities and other multilocus processes impact hybrid fitness in a rattlesnake hybrid zone. Evolution 2022; 76:2513-2530. [PMID: 36111705 DOI: 10.1111/evo.14612] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2021] [Revised: 06/24/2022] [Accepted: 08/15/2022] [Indexed: 01/22/2023]
Abstract
Hybrid zones provide valuable opportunities to understand the genomic mechanisms that promote speciation by providing insight into factors involved in intermediate stages of speciation. Here, we investigate introgression in a hybrid zone between two rattlesnake species (Crotalus viridis and Crotalus oreganus concolor) that have undergone historical allopatric divergence and recent range expansion and secondary contact. We use Bayesian genomic cline models to characterize genomic patterns of introgression between these lineages and identify loci potentially subject to selection in hybrids. We find evidence for a large number of genomic regions with biased ancestry that deviate from the genomic background in hybrids (i.e., excess ancestry loci), which tend to be associated with genomic regions with higher recombination rates. We also identify suites of excess ancestry loci that show highly correlated allele frequencies (including conspecific and heterospecific combinations) across physically unlinked genomic regions in hybrids. Our findings provide evidence for multiple multilocus evolutionary processes impacting hybrid fitness in this system.
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Affiliation(s)
- Zachary L Nikolakis
- Department of Biology, University of Texas at Arlington, Arlington, Texas, 76019
| | - Drew R Schield
- Department of Biology, University of Texas at Arlington, Arlington, Texas, 76019.,Department of Ecology and Evolutionary Biology, University of Colorado, Boulder, Colorado, 80309
| | - Aundrea K Westfall
- Department of Biology, University of Texas at Arlington, Arlington, Texas, 76019
| | - Blair W Perry
- Department of Biology, University of Texas at Arlington, Arlington, Texas, 76019
| | - Kathleen N Ivey
- Department of Biology, University of Texas at Arlington, Arlington, Texas, 76019
| | - Richard W Orton
- Department of Biology, University of Texas at Arlington, Arlington, Texas, 76019
| | - Nicole R Hales
- Department of Biology, University of Texas at Arlington, Arlington, Texas, 76019
| | - Richard H Adams
- Department of Biological and Environmental Sciences, Georgia College and State University, Milledgeville, Georgia, 31061
| | - Jesse M Meik
- Department of Biological Sciences, Tarleton State University, Stephenville, Texas, 76402
| | - Joshua M Parker
- Department of Life Sciences, Fresno City College, Fresno, California, 93741
| | - Cara F Smith
- School of Biological Sciences, University of Northern Colorado, Greeley, Colorado, 80639
| | | | - Stephen P Mackessy
- School of Biological Sciences, University of Northern Colorado, Greeley, Colorado, 80639
| | - Todd A Castoe
- Department of Biology, University of Texas at Arlington, Arlington, Texas, 76019
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26
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Shipilina D, Näsvall K, Höök L, Vila R, Talavera G, Backström N. Linkage mapping and genome annotation give novel insights into gene family expansions and regional recombination rate variation in the painted lady (Vanessa cardui) butterfly. Genomics 2022; 114:110481. [PMID: 36115505 DOI: 10.1016/j.ygeno.2022.110481] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2022] [Revised: 09/01/2022] [Accepted: 09/10/2022] [Indexed: 01/14/2023]
Abstract
Characterization of gene family expansions and crossing over is crucial for understanding how organisms adapt to the environment. Here, we develop a high-density linkage map and detailed genome annotation of the painted lady butterfly (Vanessa cardui) - a non-diapausing, highly polyphagous species famous for its long-distance migratory behavior and almost cosmopolitan distribution. Our results reveal a complex interplay between regional recombination rate variation, gene duplications and transposable element activity shaping the genome structure of the painted lady. We identify several lineage specific gene family expansions. Their functions are mainly associated with protein and fat metabolism, detoxification, and defense against infection - critical processes for the painted lady's unique life-history. Furthermore, the detailed recombination maps allow us to characterize the regional recombination landscape, data that reveal a strong effect of chromosome size on the recombination rate, a limited impact of GC-biased gene conversion and a positive association between recombination and short interspersed elements.
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Affiliation(s)
- Daria Shipilina
- Evolutionary Biology Program, Department of Ecology and Genetics, Uppsala University, Norbyvägen 18D, 75236 Uppsala, Sweden; Swedish Collegium for Advanced Study, Thunbergsvägen 2, 75236 Uppsala, Sweden.
| | - Karin Näsvall
- Evolutionary Biology Program, Department of Ecology and Genetics, Uppsala University, Norbyvägen 18D, 75236 Uppsala, Sweden
| | - Lars Höök
- Evolutionary Biology Program, Department of Ecology and Genetics, Uppsala University, Norbyvägen 18D, 75236 Uppsala, Sweden
| | - Roger Vila
- The Butterfly Diversity and Evolution Lab, Institut de Biologia Evolutiva, Passeig Martim de la Barceloneta 37-49, 08003 Barcelona, Spain
| | - Gerard Talavera
- Institut Botànic de Barcelona (IBB), CSIC-Ajuntament de Barcelona, Passeig del Migdia s/n, 08038 Barcelona, Spain
| | - Niclas Backström
- Evolutionary Biology Program, Department of Ecology and Genetics, Uppsala University, Norbyvägen 18D, 75236 Uppsala, Sweden
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27
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Provost K, Shue SY, Forcellati M, Smith BT. The Genomic Landscapes of Desert Birds Form over Multiple Time Scales. Mol Biol Evol 2022; 39:6711078. [PMID: 36134537 PMCID: PMC9577548 DOI: 10.1093/molbev/msac200] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
Spatial models show that genetic differentiation between populations can be explained by factors ranging from geographic distance to environmental resistance across the landscape. However, genomes exhibit a landscape of differentiation, indicating that multiple processes may mediate divergence in different portions of the genome. We tested this idea by comparing alternative geographic predctors of differentiation in ten bird species that co-occur in Sonoran and Chihuahuan Deserts of North America. Using population-level genomic data, we described the genomic landscapes across species and modeled conditions that represented historical and contemporary mechanisms. The characteristics of genomic landscapes differed across species, influenced by varying levels of population structuring and admixture between deserts, and the best-fit models contrasted between the whole genome and partitions along the genome. Both historical and contemporary mechanisms were important in explaining genetic distance, but particularly past and current environments, suggesting that genomic evolution was modulated by climate and habitat There were also different best-ftit models across genomic partitions of the data, indicating that these regions capture different evolutionary histories. These results show that the genomic landscape of differentiation can be associated with alternative geographic factors operating on different portions of the genome, which reflect how heterogeneous patterns of genetic differentiation can evolve across species and genomes.
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Affiliation(s)
| | - Stephanie Yun Shue
- Bergen County Academies, Hackensack, NJ, USA,Biological Sciences, University of California Berkeley, Berkeley, CA, USA
| | - Meghan Forcellati
- Bergen County Academies, Hackensack, NJ, USA,Ecology, Evolution, and Environmental Biology, Columbia University, New York, NY, USA
| | - Brian Tilston Smith
- Department of Ornithology, American Museum of Natural History, New York, NY, USA
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28
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Kvistad L, Falk S, Austin L. Widespread genomic signatures of reproductive isolation and sex-specific selection in the Eastern Yellow Robin, Eopsaltria australis. G3 GENES|GENOMES|GENETICS 2022; 12:6605223. [PMID: 35686912 PMCID: PMC9438485 DOI: 10.1093/g3journal/jkac145] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/10/2021] [Accepted: 05/31/2022] [Indexed: 11/16/2022]
Abstract
How new species evolve is one of the most fundamental questions in biology. Population divergence, which may lead to speciation, may be occurring in the Eastern Yellow Robin, a common passerine that lives along the eastern coast of Australia. This species is composed of 2 parapatric lineages that have highly divergent mitochondrial DNA; however, similar levels of divergence have not been observed in the nuclear genome. Here we re-examine the nuclear genomes of these mitolineages to test potential mechanisms underlying the discordance between nuclear and mitochondrial divergence. We find that nuclear admixture occurs in a narrow hybrid zone, although the majority of markers across the genome show evidence of reproductive isolation between populations of opposing mitolineages. There is an 8 MB section of a previously identified putative neo-sex chromosome that is highly diverged between allopatric but not parapatric populations, which may be the result of a chromosomal inversion. The neo-sex chromosomal nature of this region, as well as the geographic patterns in which it exhibits divergence, suggest it is unlikely to be contributing to reproductive isolation through mitonuclear incompatibilities as reported in earlier studies. In addition, there are sex differences in the number of markers that are differentiated between populations of opposite mitolineages, with greater differentiation occurring in females, which are heterozygous, than males. These results suggest that, despite the absence of previously observed assortative mating, mitolineages of Eastern Yellow Robin experience at least some postzygotic isolation from each other, in a pattern consistent with Haldane’s Rule.
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Affiliation(s)
- Lynna Kvistad
- Biological Sciences, Monash University , Clayton, VIC 3800, Australia
| | - Stephanie Falk
- Biological Sciences, Monash University , Clayton, VIC 3800, Australia
- Deep Sequencing Facility, Max Planck Institute of Immunobiology and Epigenetics , Freiburg D-79108, Germany
| | - Lana Austin
- Biological Sciences, Monash University , Clayton, VIC 3800, Australia
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29
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Setter D, Ebdon S, Jackson B, Lohse K. Estimating the rates of crossover and gene conversion from individual genomes. Genetics 2022; 222:6623412. [PMID: 35771626 PMCID: PMC9434185 DOI: 10.1093/genetics/iyac100] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2022] [Accepted: 06/01/2022] [Indexed: 11/14/2022] Open
Abstract
Recombination can occur either as a result of crossover or gene conversion events. Population genetic methods for inferring the rate of recombination from patterns of linkage disequilibrium generally assume a simple model of recombination that only involves crossover events and ignore gene conversion. However, distinguishing the 2 processes is not only necessary for a complete description of recombination, but also essential for understanding the evolutionary consequences of inversions and other genomic partitions in which crossover (but not gene conversion) is reduced. We present heRho, a simple composite likelihood scheme for coestimating the rate of crossover and gene conversion from individual diploid genomes. The method is based on analytic results for the distance-dependent probability of heterozygous and homozygous states at 2 loci. We apply heRho to simulations and data from the house mouse Mus musculus castaneus, a well-studied model. Our analyses show (1) that the rates of crossover and gene conversion can be accurately coestimated at the level of individual chromosomes and (2) that previous estimates of the population scaled rate of recombination ρ=4Ner under a pure crossover model are likely biased.
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Affiliation(s)
- Derek Setter
- Institute of Evolutionary Biology, University of Edinburgh, Edinburgh, EH9 3FL, UK
| | - Sam Ebdon
- Institute of Evolutionary Biology, University of Edinburgh, Edinburgh, EH9 3FL, UK
| | - Ben Jackson
- Institute of Evolutionary Biology, University of Edinburgh, Edinburgh, EH9 3FL, UK
| | - Konrad Lohse
- Institute of Evolutionary Biology, University of Edinburgh, Edinburgh, EH9 3FL, UK
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30
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Ponnikas S, Sigeman H, Lundberg M, Hansson B. Extreme variation in recombination rate and genetic diversity along the Sylvioidea neo-sex chromosome. Mol Ecol 2022; 31:3566-3583. [PMID: 35578784 PMCID: PMC9327509 DOI: 10.1111/mec.16532] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2020] [Revised: 04/13/2022] [Accepted: 05/04/2022] [Indexed: 12/03/2022]
Abstract
Recombination strongly impacts sequence evolution by affecting the extent of linkage and the efficiency of selection. Here, we study recombination over the Z chromosome in great reed warblers (Acrocephalus arundinaceus) using pedigree‐based linkage mapping. This species has extended Z and W chromosomes (“neo‐sex chromosomes”) formed by a fusion between a part of chromosome 4A and the ancestral sex chromosomes, which provides a unique opportunity to assess recombination and sequence evolution in sex‐linked regions of different ages. We assembled an 87.54 Mbp and 90.19 cM large Z with a small pseudoautosomal region (0.89 Mbp) at one end and the fused Chr4A‐part at the other end of the chromosome. A prominent feature in our data was an extreme variation in male recombination rate along Z with high values at both chromosome ends, but an apparent lack of recombination over a substantial central section, covering 78% of the chromosome. The nonrecombining region showed a drastic loss of genetic diversity and accumulation of repeats compared to the recombining parts. Thus, our data emphasize a key role of recombination in affecting local levels of polymorphism. Nonetheless, the evolutionary rate of genes (dN/dS) did not differ between high and low recombining regions, suggesting that the efficiency of selection on protein‐coding sequences can be maintained also at very low levels of recombination. Finally, the Chr4A‐derived part showed a similar recombination rate as the part of the ancestral Z that did recombine, but its sequence characteristics reflected both its previous autosomal, and current Z‐linked, recombination patterns.
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Affiliation(s)
- Suvi Ponnikas
- Department of Biology, Lund University, Lund, Sweden.,Ecology and Genetics Research Unit, University of Oulu, Oulu, Finland
| | - Hanna Sigeman
- Department of Biology, Lund University, Lund, Sweden
| | - Max Lundberg
- Department of Biology, Lund University, Lund, Sweden
| | - Bengt Hansson
- Department of Biology, Lund University, Lund, Sweden
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31
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Tigano A, Khan R, Omer AD, Weisz D, Dudchenko O, Multani AS, Pathak S, Behringer RR, Aiden EL, Fisher H, MacManes MD. Chromosome size affects sequence divergence between species through the interplay of recombination and selection. Evolution 2022; 76:782-798. [PMID: 35271737 PMCID: PMC9314927 DOI: 10.1111/evo.14467] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2021] [Accepted: 12/12/2021] [Indexed: 01/21/2023]
Abstract
The structure of the genome shapes the distribution of genetic diversity and sequence divergence. To investigate how the relationship between chromosome size and recombination rate affects sequence divergence between species, we combined empirical analyses and evolutionary simulations. We estimated pairwise sequence divergence among 15 species from three different mammalian clades-Peromyscus rodents, Mus mice, and great apes-from chromosome-level genome assemblies. We found a strong significant negative correlation between chromosome size and sequence divergence in all species comparisons within the Peromyscus and great apes clades but not the Mus clade, suggesting that the dramatic chromosomal rearrangements among Mus species may have masked the ancestral genomic landscape of divergence in many comparisons. Our evolutionary simulations showed that the main factor determining differences in divergence among chromosomes of different sizes is the interplay of recombination rate and selection, with greater variation in larger populations than in smaller ones. In ancestral populations, shorter chromosomes harbor greater nucleotide diversity. As ancestral populations diverge, diversity present at the onset of the split contributes to greater sequence divergence in shorter chromosomes among daughter species. The combination of empirical data and evolutionary simulations revealed that chromosomal rearrangements, demography, and divergence times may also affect the relationship between chromosome size and divergence, thus deepening our understanding of the role of genome structure in the evolution of species divergence.
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Affiliation(s)
- Anna Tigano
- Molecular, Cellular, and Biomedical Sciences DepartmentUniversity of New HampshireDurhamNH03824USA,Hubbard Center for Genome StudiesUniversity of New HampshireDurhamNH03824USA,Current address: Department of BiologyUniversity of British Columbia – Okanagan CampusKelownaBCV1 V 1V7Canada
| | - Ruqayya Khan
- The Center for Genome ArchitectureDepartment of Molecular and Human GeneticsBaylor College of MedicineHoustonTX77030USA
| | - Arina D. Omer
- The Center for Genome ArchitectureDepartment of Molecular and Human GeneticsBaylor College of MedicineHoustonTX77030USA
| | - David Weisz
- The Center for Genome ArchitectureDepartment of Molecular and Human GeneticsBaylor College of MedicineHoustonTX77030USA
| | - Olga Dudchenko
- The Center for Genome ArchitectureDepartment of Molecular and Human GeneticsBaylor College of MedicineHoustonTX77030USA,Department of Computer ScienceDepartment of Computational and Applied MathematicsRice UniversityHoustonTX77030USA
| | - Asha S. Multani
- Department of GeneticsM.D. Anderson Cancer CenterUniversity of TexasHoustonTX77030USA
| | - Sen Pathak
- Department of GeneticsM.D. Anderson Cancer CenterUniversity of TexasHoustonTX77030USA
| | - Richard R. Behringer
- Department of GeneticsM.D. Anderson Cancer CenterUniversity of TexasHoustonTX77030USA
| | - Erez L. Aiden
- The Center for Genome ArchitectureDepartment of Molecular and Human GeneticsBaylor College of MedicineHoustonTX77030USA,Department of Computer ScienceDepartment of Computational and Applied MathematicsRice UniversityHoustonTX77030USA,Center for Theoretical and Biological PhysicsRice UniversityHoustonTX77030USA,Shanghai Institute for Advanced Immunochemical StudiesShanghaiTech UniversityShanghai201210China,School of Agriculture and EnvironmentUniversity of Western AustraliaPerthWA6009Australia
| | - Heidi Fisher
- Department of BiologyUniversity of MarylandCollege ParkMD20742USA
| | - Matthew D. MacManes
- Molecular, Cellular, and Biomedical Sciences DepartmentUniversity of New HampshireDurhamNH03824USA,Hubbard Center for Genome StudiesUniversity of New HampshireDurhamNH03824USA
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32
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Robledo-Ruiz DA, Gan HM, Kaur P, Dudchenko O, Weisz D, Khan R, Lieberman Aiden E, Osipova E, Hiller M, Morales HE, Magrath MJL, Clarke RH, Sunnucks P, Pavlova A. Chromosome-length genome assembly and linkage map of a critically endangered Australian bird: the helmeted honeyeater. Gigascience 2022; 11:giac025. [PMID: 35348671 PMCID: PMC8963300 DOI: 10.1093/gigascience/giac025] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2021] [Revised: 01/13/2022] [Accepted: 02/14/2022] [Indexed: 11/17/2022] Open
Abstract
BACKGROUND The helmeted honeyeater (Lichenostomus melanops cassidix) is a Critically Endangered bird endemic to Victoria, Australia. To aid its conservation, the population is the subject of genetic rescue. To understand, monitor, and modulate the effects of genetic rescue on the helmeted honeyeater genome, a chromosome-length genome and a high-density linkage map are required. RESULTS We used a combination of Illumina, Oxford Nanopore, and Hi-C sequencing technologies to assemble a chromosome-length genome of the helmeted honeyeater, comprising 906 scaffolds, with length of 1.1 Gb and scaffold N50 of 63.8 Mb. Annotation comprised 57,181 gene models. Using a pedigree of 257 birds and 53,111 single-nucleotide polymorphisms, we obtained high-density linkage and recombination maps for 25 autosomes and Z chromosome. The total sex-averaged linkage map was 1,347 cM long, with the male map being 6.7% longer than the female map. Recombination maps revealed sexually dimorphic recombination rates (overall higher in males), with average recombination rate of 1.8 cM/Mb. Comparative analyses revealed high synteny of the helmeted honeyeater genome with that of 3 passerine species (e.g., 32 Hi-C scaffolds mapped to 30 zebra finch autosomes and Z chromosome). The genome assembly and linkage map suggest that the helmeted honeyeater exhibits a fission of chromosome 1A into 2 chromosomes relative to zebra finch. PSMC analysis showed a ∼15-fold decline in effective population size to ∼60,000 from mid- to late Pleistocene. CONCLUSIONS The annotated chromosome-length genome and high-density linkage map provide rich resources for evolutionary studies and will be fundamental in guiding conservation efforts for the helmeted honeyeater.
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Affiliation(s)
| | - Han Ming Gan
- Deakin Genomics Centre, Deakin University, Geelong, VIC 3220, Australia
- GeneSEQ Sdn Bhd, 48300 Rawang, Selangor, Malaysia
| | - Parwinder Kaur
- UWA School of Agriculture and Environment, The University of Western Australia, Perth WA 6009,Australia
| | - Olga Dudchenko
- The Center for Genome Architecture, Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA
- Center for Theoretical Biological Physics and Department of Computer Science, Rice University, Houston, TX 77030, USA
| | - David Weisz
- The Center for Genome Architecture, Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA
| | - Ruqayya Khan
- The Center for Genome Architecture, Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA
| | - Erez Lieberman Aiden
- UWA School of Agriculture and Environment, The University of Western Australia, Perth WA 6009,Australia
- The Center for Genome Architecture, Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA
- Center for Theoretical Biological Physics and Department of Computer Science, Rice University, Houston, TX 77030, USA
- Broad Institute of MIT and Harvard, Cambridge, MA 02139, USA
- Shanghai Institute for Advanced Immunochemical Studies, ShanghaiTech, Pudong 201210, China
| | - Ekaterina Osipova
- Max Planck Institute of Molecular Cell Biology and Genetics, Pfotenhauerstr 108, 101307 Dresden, Germany
- LOEWE Centre for Translational Biodiversity Genomics, Senckenberganlage 25, 60325 Frankfurt, Germany
- Senckenberg Research Institute, Senckenberganlage 25, 60325 Frankfurt, Germany
- Goethe-University, Faculty of Biosciences, Max-von-Laue-Str. 9, 60438 Frankfurt, Germany
| | - Michael Hiller
- Max Planck Institute of Molecular Cell Biology and Genetics, Pfotenhauerstr 108, 101307 Dresden, Germany
- LOEWE Centre for Translational Biodiversity Genomics, Senckenberganlage 25, 60325 Frankfurt, Germany
- Senckenberg Research Institute, Senckenberganlage 25, 60325 Frankfurt, Germany
- Goethe-University, Faculty of Biosciences, Max-von-Laue-Str. 9, 60438 Frankfurt, Germany
| | - Hernán E Morales
- Section for Evolutionary Genomics, GLOBE Institute, University of Copenhagen, Denmark
| | - Michael J L Magrath
- Department of Wildlife Conservation and Science, Zoos Victoria, Parkville, VIC 3052, Australia
| | - Rohan H Clarke
- School of Biological Sciences, Monash University, Clayton, VIC 3800, Australia
| | - Paul Sunnucks
- School of Biological Sciences, Monash University, Clayton, VIC 3800, Australia
| | - Alexandra Pavlova
- School of Biological Sciences, Monash University, Clayton, VIC 3800, Australia
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33
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Sigeman H, Strandh M, Proux-Wéra E, Kutschera VE, Ponnikas S, Zhang H, Lundberg M, Soler L, Bunikis I, Tarka M, Hasselquist D, Nystedt B, Westerdahl H, Hansson B. Avian Neo-Sex Chromosomes Reveal Dynamics of Recombination Suppression and W Degeneration. Mol Biol Evol 2021; 38:5275-5291. [PMID: 34542640 PMCID: PMC8662655 DOI: 10.1093/molbev/msab277] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
How the avian sex chromosomes first evolved from autosomes remains elusive as 100 million years (My) of divergence and degeneration obscure their evolutionary history. The Sylvioidea group of songbirds is interesting for understanding avian sex chromosome evolution because a chromosome fusion event ∼24 Ma formed "neo-sex chromosomes" consisting of an added (new) and an ancestral (old) part. Here, we report the complete female genome (ZW) of one Sylvioidea species, the great reed warbler (Acrocephalus arundinaceus). Our long-read assembly shows that the added region has been translocated to both Z and W, and whereas the added-Z has retained its gene order the added-W part has been heavily rearranged. Phylogenetic analyses show that recombination between the homologous added-Z and -W regions continued after the fusion event, and that recombination suppression across this region took several million years to be completed. Moreover, recombination suppression was initiated across multiple positions over the added-Z, which is not consistent with a simple linear progression starting from the fusion point. As expected following recombination suppression, the added-W show signs of degeneration including repeat accumulation and gene loss. Finally, we present evidence for nonrandom maintenance of slowly evolving and dosage-sensitive genes on both ancestral- and added-W, a process causing correlated evolution among orthologous genes across broad taxonomic groups, regardless of sex linkage.
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Affiliation(s)
- Hanna Sigeman
- Department of Biology, Lund University, Lund, Sweden
| | - Maria Strandh
- Department of Biology, Lund University, Lund, Sweden
| | - Estelle Proux-Wéra
- Department of Biochemistry and Biophysics, National Bioinformatics Infrastructure Sweden, Science for Life Laboratory, Stockholm University, Solna, Sweden
| | - Verena E Kutschera
- Department of Biochemistry and Biophysics, National Bioinformatics Infrastructure Sweden, Science for Life Laboratory, Stockholm University, Solna, Sweden
| | - Suvi Ponnikas
- Department of Biology, Lund University, Lund, Sweden
| | - Hongkai Zhang
- Department of Biology, Lund University, Lund, Sweden
| | - Max Lundberg
- Department of Biology, Lund University, Lund, Sweden
| | - Lucile Soler
- Department of Medical Biochemistry and Microbiology, National Bioinformatics Infrastructure Sweden, Science for Life Laboratory, Uppsala University, Uppsala, Sweden
| | - Ignas Bunikis
- Department of Immunology, Genetics and Pathology, Science for Life Laboratory, Uppsala Genome Center, Uppsala University, Uppsala, Sweden
| | - Maja Tarka
- Department of Biology, Lund University, Lund, Sweden
| | | | - Björn Nystedt
- Department of Cell and Molecular Biology, National Bioinformatics Infrastructure Sweden, Science for Life Laboratory, Uppsala University, Uppsala, Sweden
| | | | - Bengt Hansson
- Department of Biology, Lund University, Lund, Sweden
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34
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Turbek SP, Semenov GA, Enbody ED, Campagna L, Taylor SA. Variable Signatures of Selection Despite Conserved Recombination Landscapes Early in Speciation. J Hered 2021; 112:485-496. [PMID: 34499149 DOI: 10.1093/jhered/esab054] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2021] [Accepted: 09/08/2021] [Indexed: 11/14/2022] Open
Abstract
Recently diverged taxa often exhibit heterogeneous landscapes of genomic differentiation, characterized by regions of elevated differentiation on an otherwise homogeneous background. While divergence peaks are generally interpreted as regions responsible for reproductive isolation, they can also arise due to background selection, selective sweeps unrelated to speciation, and variation in recombination and mutation rates. To investigate the association between patterns of recombination and landscapes of genomic differentiation during the early stages of speciation, we generated fine-scale recombination maps for six southern capuchino seedeaters (Sporophila) and two subspecies of White Wagtail (Motacilla alba), two recent avian radiations in which divergent selection on pigmentation genes has likely generated peaks of differentiation. We compared these recombination maps to those of Collared (Ficedula albicollis) and Pied Flycatchers (Ficedula hypoleuca), non-sister taxa characterized by moderate genomic divergence and a heterogenous landscape of genomic differentiation shaped in part by background selection. Although recombination landscapes were conserved within all three systems, we documented a weaker negative correlation between recombination rate and genomic differentiation in the recent radiations. All divergence peaks between capuchinos, wagtails, and flycatchers were located in regions with lower-than-average recombination rates, and most divergence peaks in capuchinos and flycatchers fell in regions of exceptionally reduced recombination. Thus, co-adapted allelic combinations in these regions may have been protected early in divergence, facilitating rapid diversification. Despite largely conserved recombination landscapes, divergence peaks are specific to each focal comparison in capuchinos, suggesting that regions of elevated differentiation have not been generated by variation in recombination rate alone.
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Affiliation(s)
- Sheela P Turbek
- Department of Ecology and Evolutionary Biology, University of Colorado, Boulder, CO, USA
| | - Georgy A Semenov
- Department of Ecology and Evolutionary Biology, University of Colorado, Boulder, CO, USA
| | - Erik D Enbody
- Department of Medical Biochemistry and Microbiology, Uppsala University, Uppsala, Sweden
| | - Leonardo Campagna
- Fuller Evolutionary Biology Program, Cornell Lab of Ornithology, Ithaca, NY, USA.,Department of Ecology and Evolutionary Biology, Cornell University, Ithaca, NY, USA
| | - Scott A Taylor
- Department of Ecology and Evolutionary Biology, University of Colorado, Boulder, CO, USA
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35
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Galla SJ, Brown L, Couch-Lewis Ngāi Tahu Te Hapū O Ngāti Wheke Ngāti Waewae Y, Cubrinovska I, Eason D, Gooley RM, Hamilton JA, Heath JA, Hauser SS, Latch EK, Matocq MD, Richardson A, Wold JR, Hogg CJ, Santure AW, Steeves TE. The relevance of pedigrees in the conservation genomics era. Mol Ecol 2021; 31:41-54. [PMID: 34553796 PMCID: PMC9298073 DOI: 10.1111/mec.16192] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2021] [Revised: 09/12/2021] [Accepted: 09/17/2021] [Indexed: 01/21/2023]
Abstract
Over the past 50 years conservation genetics has developed a substantive toolbox to inform species management. One of the most long‐standing tools available to manage genetics—the pedigree—has been widely used to characterize diversity and maximize evolutionary potential in threatened populations. Now, with the ability to use high throughput sequencing to estimate relatedness, inbreeding, and genome‐wide functional diversity, some have asked whether it is warranted for conservation biologists to continue collecting and collating pedigrees for species management. In this perspective, we argue that pedigrees remain a relevant tool, and when combined with genomic data, create an invaluable resource for conservation genomic management. Genomic data can address pedigree pitfalls (e.g., founder relatedness, missing data, uncertainty), and in return robust pedigrees allow for more nuanced research design, including well‐informed sampling strategies and quantitative analyses (e.g., heritability, linkage) to better inform genomic inquiry. We further contend that building and maintaining pedigrees provides an opportunity to strengthen trusted relationships among conservation researchers, practitioners, Indigenous Peoples, and Local Communities.
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Affiliation(s)
- Stephanie J Galla
- Department of Biological Sciences, Boise State University, Boise, Idaho, USA.,School of Biological Sciences, University of Canterbury, Christchurch, Canterbury, New Zealand
| | - Liz Brown
- New Zealand Department of Conservation, Twizel, Canterbury, New Zealand
| | | | - Ilina Cubrinovska
- School of Biological Sciences, University of Canterbury, Christchurch, Canterbury, New Zealand
| | - Daryl Eason
- New Zealand Department of Conservation, Invercargill, Southland, New Zealand
| | - Rebecca M Gooley
- Smithsonian-Mason School of Conservation, Front Royal, Maryland, USA.,Center for Species Survival, Smithsonian Conservation Biology Institute, National Zoological Park, Washington, District of Columbia, USA
| | - Jill A Hamilton
- Department of Biological Sciences, North Dakota State University, Fargo, North Dakota, USA
| | - Julie A Heath
- Department of Biological Sciences, Boise State University, Boise, Idaho, USA
| | - Samantha S Hauser
- Department of Biological Sciences, University of Wisconsin-Milwaukee, Milwaukee, Wisconsin, USA
| | - Emily K Latch
- Department of Biological Sciences, University of Wisconsin-Milwaukee, Milwaukee, Wisconsin, USA
| | - Marjorie D Matocq
- Department of Natural Resources and Environmental Science, Program in Ecology, Evolution and Conservation Biology, University of Nevada Reno, Reno, Nevada, USA
| | - Anne Richardson
- The Isaac Conservation and Wildlife Trust, Christchurch, Canterbury, New Zealand
| | - Jana R Wold
- School of Biological Sciences, University of Canterbury, Christchurch, Canterbury, New Zealand
| | - Carolyn J Hogg
- School of Life and Environmental Sciences, University of Sydney, Sydney, NSW, Australia
| | - Anna W Santure
- School of Biological Sciences, University of Auckland, Auckland, Auckland, New Zealand
| | - Tammy E Steeves
- School of Biological Sciences, University of Canterbury, Christchurch, Canterbury, New Zealand
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36
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Srikulnath K, Ahmad SF, Singchat W, Panthum T. Why Do Some Vertebrates Have Microchromosomes? Cells 2021; 10:2182. [PMID: 34571831 PMCID: PMC8466491 DOI: 10.3390/cells10092182] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2021] [Revised: 08/17/2021] [Accepted: 08/17/2021] [Indexed: 12/27/2022] Open
Abstract
With more than 70,000 living species, vertebrates have a huge impact on the field of biology and research, including karyotype evolution. One prominent aspect of many vertebrate karyotypes is the enigmatic occurrence of tiny and often cytogenetically indistinguishable microchromosomes, which possess distinctive features compared to macrochromosomes. Why certain vertebrate species carry these microchromosomes in some lineages while others do not, and how they evolve remain open questions. New studies have shown that microchromosomes exhibit certain unique characteristics of genome structure and organization, such as high gene densities, low heterochromatin levels, and high rates of recombination. Our review focuses on recent concepts to expand current knowledge on the dynamic nature of karyotype evolution in vertebrates, raising important questions regarding the evolutionary origins and ramifications of microchromosomes. We introduce the basic karyotypic features to clarify the size, shape, and morphology of macro- and microchromosomes and report their distribution across different lineages. Finally, we characterize the mechanisms of different evolutionary forces underlying the origin and evolution of microchromosomes.
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Affiliation(s)
- Kornsorn Srikulnath
- Animal Genomics and Bioresource Research Center (AGB Research Center), Faculty of Science, Kasetsart University, 50 Ngamwongwan, Chatuchak, Bangkok 10900, Thailand; (S.F.A.); (W.S.); (T.P.)
- Laboratory of Animal Cytogenetics and Comparative Genomics (ACCG), Department of Genetics, Faculty of Science, Kasetsart University, 50 Ngamwongwan, Chatuchak, Bangkok 10900, Thailand
- The International Undergraduate Program in Bioscience and Technology, Faculty of Science, Kasetsart University, 50 Ngamwongwan, Chatuchak, Bangkok 10900, Thailand
- Special Research Unit for Wildlife Genomics (SRUWG), Department of Forest Biology, Faculty of Forestry, Kasetsart University, 50 Ngamwongwan, Chatuchak, Bangkok 10900, Thailand
- Amphibian Research Center, Hiroshima University, 1-3-1, Kagamiyama, Higashihiroshima 739-8526, Japan
| | - Syed Farhan Ahmad
- Animal Genomics and Bioresource Research Center (AGB Research Center), Faculty of Science, Kasetsart University, 50 Ngamwongwan, Chatuchak, Bangkok 10900, Thailand; (S.F.A.); (W.S.); (T.P.)
- Laboratory of Animal Cytogenetics and Comparative Genomics (ACCG), Department of Genetics, Faculty of Science, Kasetsart University, 50 Ngamwongwan, Chatuchak, Bangkok 10900, Thailand
- The International Undergraduate Program in Bioscience and Technology, Faculty of Science, Kasetsart University, 50 Ngamwongwan, Chatuchak, Bangkok 10900, Thailand
- Special Research Unit for Wildlife Genomics (SRUWG), Department of Forest Biology, Faculty of Forestry, Kasetsart University, 50 Ngamwongwan, Chatuchak, Bangkok 10900, Thailand
| | - Worapong Singchat
- Animal Genomics and Bioresource Research Center (AGB Research Center), Faculty of Science, Kasetsart University, 50 Ngamwongwan, Chatuchak, Bangkok 10900, Thailand; (S.F.A.); (W.S.); (T.P.)
- Laboratory of Animal Cytogenetics and Comparative Genomics (ACCG), Department of Genetics, Faculty of Science, Kasetsart University, 50 Ngamwongwan, Chatuchak, Bangkok 10900, Thailand
- Special Research Unit for Wildlife Genomics (SRUWG), Department of Forest Biology, Faculty of Forestry, Kasetsart University, 50 Ngamwongwan, Chatuchak, Bangkok 10900, Thailand
| | - Thitipong Panthum
- Animal Genomics and Bioresource Research Center (AGB Research Center), Faculty of Science, Kasetsart University, 50 Ngamwongwan, Chatuchak, Bangkok 10900, Thailand; (S.F.A.); (W.S.); (T.P.)
- Laboratory of Animal Cytogenetics and Comparative Genomics (ACCG), Department of Genetics, Faculty of Science, Kasetsart University, 50 Ngamwongwan, Chatuchak, Bangkok 10900, Thailand
- Special Research Unit for Wildlife Genomics (SRUWG), Department of Forest Biology, Faculty of Forestry, Kasetsart University, 50 Ngamwongwan, Chatuchak, Bangkok 10900, Thailand
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37
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Manthey JD, Klicka J, Spellman GM. The Genomic Signature of Allopatric Speciation in a Songbird Is Shaped by Genome Architecture (Aves: Certhia americana). Genome Biol Evol 2021; 13:evab120. [PMID: 34042960 PMCID: PMC8364988 DOI: 10.1093/gbe/evab120] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/24/2021] [Indexed: 12/31/2022] Open
Abstract
The genomic signature of speciation with gene flow is often attributed to the strength of divergent selection and recombination rate in regions harboring targets for selection. In contrast, allopatric speciation provides a different geographic context and evolutionary scenario, whereby introgression is limited by isolation rather than selection against gene flow. Lacking shared divergent selection or selection against hybridization, we would predict the genomic signature of allopatric speciation would largely be shaped by genomic architecture-the nonrandom distribution of functional elements and chromosomal characteristics-through its role in affecting the processes of selection and drift. Here, we built and annotated a chromosome-scale genome assembly for a songbird (Passeriformes: Certhia americana). We show that the genomic signature of allopatric speciation between its two primary lineages is largely shaped by genomic architecture. Regionally, gene density and recombination rate variation explain a large proportion of variance in genomic diversity, differentiation, and divergence. We identified a heterogeneous landscape of selection and neutrality, with a large portion of the genome under the effects of indirect selection. We found higher proportions of small chromosomes under the effects of indirect selection, likely because they have relatively higher gene density. At the chromosome scale, differential genomic architecture of macro- and microchromosomes shapes the genomic signatures of speciation: chromosome size has: 1) a positive relationship with genetic differentiation, genetic divergence, rate of lineage sorting in the contact zone, and proportion neutral evolution and 2) a negative relationship with genetic diversity and recombination rate.
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Affiliation(s)
- Joseph D Manthey
- Department of Biological Sciences, Texas Tech University, Lubbock, Texas, USA
| | - John Klicka
- Burke Museum of Natural History, University of Washington, Seattle, Washington, USA
- Department of Biology, University of Washington, Seattle, Washington, USA
| | - Garth M Spellman
- Department of Zoology, Denver Museum of Nature & Science, Denver, Colorado, USA
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38
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Hasan AR, Ness RW. Recombination Rate Variation and Infrequent Sex Influence Genetic Diversity in Chlamydomonas reinhardtii. Genome Biol Evol 2021; 12:370-380. [PMID: 32181819 PMCID: PMC7186780 DOI: 10.1093/gbe/evaa057] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 03/13/2020] [Indexed: 12/12/2022] Open
Abstract
Recombination confers a major evolutionary advantage by breaking up linkage disequilibrium between harmful and beneficial mutations, thereby facilitating selection. However, in species that are only periodically sexual, such as many microbial eukaryotes, the realized rate of recombination is also affected by the frequency of sex, meaning that infrequent sex can increase the effects of selection at linked sites despite high recombination rates. Despite this, the rate of sex of most facultatively sexual species is unknown. Here, we use genomewide patterns of linkage disequilibrium to infer fine-scale recombination rate variation in the genome of the facultatively sexual green alga Chlamydomonas reinhardtii. We observe recombination rate variation of up to two orders of magnitude and find evidence of recombination hotspots across the genome. Recombination rate is highest flanking genes, consistent with trends observed in other nonmammalian organisms, though intergenic recombination rates vary by intergenic tract length. We also find a positive relationship between nucleotide diversity and physical recombination rate, suggesting a widespread influence of selection at linked sites in the genome. Finally, we use estimates of the effective rate of recombination to calculate the rate of sex that occurs in natural populations, estimating a sexual cycle roughly every 840 generations. We argue that the relatively infrequent rate of sex and large effective population size creates a population genetic environment that increases the influence of selection on linked sites across the genome.
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Affiliation(s)
- Ahmed R Hasan
- Department of Cell and Systems Biology, University of Toronto, Ontario, Canada.,Department of Biology, University of Toronto Mississauga, Ontario, Canada
| | - Rob W Ness
- Department of Cell and Systems Biology, University of Toronto, Ontario, Canada.,Department of Biology, University of Toronto Mississauga, Ontario, Canada
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39
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Nadachowska-Brzyska K, Dutoit L, Smeds L, Kardos M, Gustafsson L, Ellegren H. Genomic inference of contemporary effective population size in a large island population of collared flycatchers (Ficedula albicollis). Mol Ecol 2021; 30:3965-3973. [PMID: 34145933 DOI: 10.1111/mec.16025] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2020] [Revised: 05/28/2021] [Accepted: 06/01/2021] [Indexed: 12/30/2022]
Abstract
Due to its central importance to many aspects of evolutionary biology and population genetics, the long-term effective population size (Ne ) has been estimated for numerous species and populations. However, estimating contemporary Ne is difficult and in practice this parameter is often unknown. In principle, contemporary Ne can be estimated using either analyses of temporal changes in allele frequencies, or the extent of linkage disequilibrium (LD) between unlinked markers. We applied these approaches to estimate contemporary Ne of a relatively recently founded island population of collared flycatchers (Ficedula albicollis). We sequenced the genomes of 85 birds sampled in 1993 and 2015, and applied several temporal methods to estimate Ne at a few thousand (4000-7000). The approach based on LD provided higher estimates of Ne (20,000-32,000) and was associated with high variance, often resulting in infinite Ne . We conclude that whole-genome sequencing data offers new possibilities to estimate high (>1000) contemporary Ne , but also note that such estimates remain challenging, in particular for LD-based methods for contemporary Ne estimation.
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Affiliation(s)
- Krystyna Nadachowska-Brzyska
- Department of Evolutionary Biology, Evolutionary Biology Centre, Uppsala University, Uppsala, Sweden.,Institute of Environmental Sciences, Jagiellonian University, Kraków, Poland
| | - Ludovic Dutoit
- Department of Evolutionary Biology, Evolutionary Biology Centre, Uppsala University, Uppsala, Sweden.,Department of Zoology, University of Otago, Dunedin, New Zealand
| | - Linnéa Smeds
- Department of Evolutionary Biology, Evolutionary Biology Centre, Uppsala University, Uppsala, Sweden
| | - Martin Kardos
- Northwest Fisheries Science Center, National Marine Fisheries Service, National Oceanic and Atmospheric Administration, Seattle, WA, USA
| | - Lars Gustafsson
- Department of Animal Ecology, Evolutionary Biology Centre, Uppsala University, Uppsala, Sweden
| | - Hans Ellegren
- Department of Evolutionary Biology, Evolutionary Biology Centre, Uppsala University, Uppsala, Sweden
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40
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Mikkelsen EK, Irwin D. Ongoing production of low-fitness hybrids limits range overlap between divergent cryptic species. Mol Ecol 2021; 30:4090-4102. [PMID: 34101940 DOI: 10.1111/mec.16015] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2019] [Revised: 05/13/2021] [Accepted: 05/26/2021] [Indexed: 01/23/2023]
Abstract
Contact zones between recently diverged taxa provide opportunities to examine the causes of reproductive isolation and the processes that determine whether two species can coexist over a broad region. The Pacific wren (Troglodytes pacificus) and winter wren (Troglodytes hiemalis) are two morphologically similar songbirds that started diverging about 4 million years ago, older than most sister species pairs of temperate songbirds. The ranges of these species come into narrow contact in western Canada, where the two species remain distinct. To assess evidence for differentiation, hybridization and introgression in this system, we examined variation in over 250,000 single nucleotide polymorphism markers distributed across the genome. The two species formed highly divergent genetic clusters, consistent with long-term differentiation. In a set of 75 individuals, two first-generation hybrids (i.e., F1 's) were detected, indicating only moderate levels of assortative mating between these taxa. We found no recent backcrosses or other evidence of recent breeding success of F1 's, indicating very low or zero fitness of F1 hybrids. Examination of genomic variation shows evidence for only a single backcrossing event many generations ago. The moderate rate of hybridization combined with very low F1 hybrid fitness is expected to result in a population sink in the contact zone, largely explaining the narrow overlap of the two species. If such dynamics are common in nature, they could explain the narrow range overlap often observed between pairs of closely related species.
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Affiliation(s)
- Else K Mikkelsen
- Department of Zoology, and Biodiversity Research Centre, University of British Columbia, Vancouver, BC, Canada.,Department of Ecology and Evolutionary Biology, University of Toronto, Toronto, ON, Canada
| | - Darren Irwin
- Department of Zoology, and Biodiversity Research Centre, University of British Columbia, Vancouver, BC, Canada
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41
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Martini D, Dussex N, Robertson BC, Gemmell NJ, Knapp M. Evolution of the "world's only alpine parrot": Genomic adaptation or phenotypic plasticity, behaviour and ecology? Mol Ecol 2021; 30:6370-6386. [PMID: 33973288 DOI: 10.1111/mec.15978] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2020] [Revised: 04/19/2021] [Accepted: 04/28/2021] [Indexed: 02/06/2023]
Abstract
Climate warming, in particular in island environments, where opportunities for species to disperse are limited, may become a serious threat to cold adapted alpine species. In order to understand how alpine species may respond to a warming world, we need to understand the drivers that have shaped their habitat specialisation and the evolutionary adaptations that allow them to utilize alpine habitats. The endemic, endangered New Zealand kea (Nestor notabilis) is considered the only alpine parrot in the world. As a species commonly found in the alpine zone it may be highly susceptible to climate warming. But is it a true alpine specialist? Is its evolution driven by adaptation to the alpine zone, or is the kea an open habitat generalist that simply uses the alpine zone to, for example, avoid lower lying anthropogenic landscapes? We use whole genome data of the kea and its close, forest adapted sister species, the kākā (Nestor meridionalis) to reconstruct the evolutionary history of both species and identify the functional genomic differences that underlie their habitat specialisations. Our analyses do not identify major functional genomic differences between kea and kākā in pathways associated with high-altitude. Rather, we found evidence that selective pressures on adaptations commonly found in alpine species are present in both Nestor species, suggesting that selection for alpine adaptations has not driven their divergence. Strongly divergent demographic responses to past climate warming between the species nevertheless highlight potential future threats to kea survival in a warming world.
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Affiliation(s)
- Denise Martini
- Department of Anatomy, University of Otago, Dunedin, New Zealand
| | - Nicolas Dussex
- Centre for Palaeogenetics, Stockholm, Sweden.,Department of Bioinformatics and Genetics, Swedish Museum of Natural History, Stockholm, Sweden.,Department of Zoology, Stockholm University, Stockholm, Sweden
| | | | - Neil J Gemmell
- Department of Anatomy, University of Otago, Dunedin, New Zealand
| | - Michael Knapp
- Department of Anatomy, University of Otago, Dunedin, New Zealand
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42
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Chase MA, Ellegren H, Mugal CF. Positive selection plays a major role in shaping signatures of differentiation across the genomic landscape of two independent Ficedula flycatcher species pairs. Evolution 2021; 75:2179-2196. [PMID: 33851440 DOI: 10.1111/evo.14234] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2020] [Revised: 03/05/2021] [Accepted: 03/17/2021] [Indexed: 12/30/2022]
Abstract
A current debate within population genomics surrounds the relevance of patterns of genomic differentiation between closely related species for our understanding of adaptation and speciation. Mounting evidence across many taxa suggests that the same genomic regions repeatedly develop elevated differentiation in independent species pairs. These regions often coincide with high gene density and/or low recombination, leading to the hypothesis that the genomic differentiation landscape mostly reflects a history of background selection, and reveals little about adaptation or speciation. A comparative genomics approach with multiple independent species pairs at a timescale where gene flow and ILS are negligible permits investigating whether different evolutionary processes are responsible for generating lineage-specific versus shared patterns of species differentiation. We use whole-genome resequencing data of 195 individuals from four Ficedula flycatcher species comprising two independent species pairs: collared and pied flycatchers, and red-breasted and taiga flycatchers. We found that both shared and lineage-specific FST peaks could partially be explained by selective sweeps, with recurrent selection likely to underlie shared signatures of selection, whereas indirect evidence supports a role of recombination landscape evolution in driving lineage-specific signatures of selection. This work therefore provides evidence for an interplay of positive selection and recombination to genomic landscape evolution.
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Affiliation(s)
- Madeline A Chase
- Department of Evolutionary Biology, Evolutionary Biology Centre, Uppsala university, Uppsala, SE-75236, Sweden
| | - Hans Ellegren
- Department of Evolutionary Biology, Evolutionary Biology Centre, Uppsala university, Uppsala, SE-75236, Sweden
| | - Carina F Mugal
- Department of Evolutionary Biology, Evolutionary Biology Centre, Uppsala university, Uppsala, SE-75236, Sweden
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43
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Cockburn A, Peñalba JV, Jaccoud D, Kilian A, Brouwer L, Double MC, Margraf N, Osmond HL, Kruuk LEB, van de Pol M. hiphop: Improved paternity assignment among close relatives using a simple exclusion method for biallelic markers. Mol Ecol Resour 2021; 21:1850-1865. [PMID: 33750003 DOI: 10.1111/1755-0998.13389] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2020] [Revised: 03/08/2021] [Accepted: 03/15/2021] [Indexed: 11/30/2022]
Abstract
Assignment of parentage with molecular markers is most difficult when the true parents have close relatives in the adult population. Here, we present an efficient solution to that problem by extending simple exclusion approaches to parentage analysis with single nucleotide polymorphic markers (SNPs). We augmented the previously published homozygote opposite test (hot), which counts mismatches due to the offspring and candidate parent having different homozygous genotypes, with an additional test. In this case, parents homozygous for the same SNP are incompatible with heterozygous offspring (i.e., "Homozygous Identical Parents, Heterozygous Offspring are Precluded": hiphop). We tested this approach in a cooperatively breeding bird, the superb fairy-wren, Malurus cyaneus, where rates of extra-pair paternity are exceptionally high, and where paternity assignment is challenging because breeding males typically have first-order adult relatives in their neighbourhood. Combining the tests and conditioning on the maternal genotype with a set of 1376 autosomal SNPs always allowed us to distinguish a single most likely sire from his relatives, and also to identify cases where the true sire must have been unsampled. In contrast, if just the hot test was used, we failed to identify a single most-likely sire in 2.5% of cases. Resampling enabled us to create guidelines for the number of SNPs required when first-order relatives coexist in the mating pool. Our method, implemented in the R package hiphop, therefore provides unambiguous parentage assignments even in systems with complex social organisation. We also identified a suite of Z- and W-linked SNPs that always identified sex correctly.
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Affiliation(s)
- Andrew Cockburn
- Division of Ecology and Evolution, Research School of Biology, The Australian National University, Canberra, ACT, Australia
| | - Joshua V Peñalba
- Division of Ecology and Evolution, Research School of Biology, The Australian National University, Canberra, ACT, Australia.,Division of Evolutionary Biology, Ludwig Maximilians Universitat Munchen, Munchen, Germany
| | - Damian Jaccoud
- Diversity Arrays Technology Pty Ltd, Bruce, ACT, Australia
| | - Andrzej Kilian
- Diversity Arrays Technology Pty Ltd, Bruce, ACT, Australia
| | - Lyanne Brouwer
- Division of Ecology and Evolution, Research School of Biology, The Australian National University, Canberra, ACT, Australia.,Department of Animal Ecology and Physiology, Radboud University, Nijmegen, The Netherlands
| | - Michael C Double
- Division of Ecology and Evolution, Research School of Biology, The Australian National University, Canberra, ACT, Australia.,Australian Antarctic Division, Kingston, TAS, Australia
| | - Nicolas Margraf
- Division of Ecology and Evolution, Research School of Biology, The Australian National University, Canberra, ACT, Australia.,Musée d'histoire naturelle de La Chaux-de-Fonds, Neuchatel, Switzerland
| | - Helen L Osmond
- Division of Ecology and Evolution, Research School of Biology, The Australian National University, Canberra, ACT, Australia
| | - Loeske E B Kruuk
- Division of Ecology and Evolution, Research School of Biology, The Australian National University, Canberra, ACT, Australia
| | - Martijn van de Pol
- Division of Ecology and Evolution, Research School of Biology, The Australian National University, Canberra, ACT, Australia.,Netherlands Institute of Ecology, Wageningen, The Netherlands
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44
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Schreiber D, Pfenninger M. Genomic divergence landscape in recurrently hybridizing Chironomus sister taxa suggests stable steady state between mutual gene flow and isolation. Evol Lett 2021; 5:86-100. [PMID: 33552538 PMCID: PMC7857304 DOI: 10.1002/evl3.204] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2020] [Revised: 09/11/2020] [Accepted: 10/19/2020] [Indexed: 12/30/2022] Open
Abstract
Divergence is mostly viewed as a progressive process often initiated by selection targeting individual loci, ultimately resulting in ever increasing genomic isolation due to linkage. However, recent studies show that this process may stall at intermediate stable equilibrium states without achieving complete genomic isolation. We tested the extent of genomic isolation between two recurrently hybridizing nonbiting midge sister taxa, Chironomus riparius and Chironomus piger, by analyzing the divergence landscape. Using a principal component-based method, we estimated that only about 28.44% of the genomes were mutually isolated, whereas the rest was still exchanged. The divergence landscape was fragmented into isolated regions of on average 30 kb, distributed throughout the genome. Selection and divergence time strongly influenced lengths of isolated regions, whereas local recombination rate only had minor impact. Comparison of divergence time distributions obtained from several coalescence-simulated divergence scenarios with the observed divergence time estimates in an approximate Bayesian computation framework favored a short and concluded divergence event in the past. Most divergence happened during a short time span about 4.5 million generations ago, followed by a stable equilibrium between mutual gene flow through ongoing hybridization for the larger part of the genome and isolation in some regions due to rapid purifying selection of introgression, supported by high effective population sizes and recombination rates.
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Affiliation(s)
- Dennis Schreiber
- Department of Molecular EcologySenckenberg Biodiversity and Climate Research CentreFrankfurt am Main60325Germany
- Institute for Molecular and Organismic EvolutionJohannes Gutenberg UniversityMainz55128Germany
| | - Markus Pfenninger
- Department of Molecular EcologySenckenberg Biodiversity and Climate Research CentreFrankfurt am Main60325Germany
- Institute for Molecular and Organismic EvolutionJohannes Gutenberg UniversityMainz55128Germany
- LOEWE Centre for Translational Biodiversity Genomics (LOEWE‐TBG)Frankfurt am Main60325Germany
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45
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Island songbirds as windows into evolution in small populations. Curr Biol 2021; 31:1303-1310.e4. [PMID: 33476557 DOI: 10.1016/j.cub.2020.12.040] [Citation(s) in RCA: 32] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2020] [Revised: 10/12/2020] [Accepted: 12/23/2020] [Indexed: 11/20/2022]
Abstract
Due to their limited ranges and inherent isolation, island species have long been recognized as crucial systems for tackling a range of evolutionary questions, including in the early study of speciation.1,2 Such species have been less studied in the understanding of the evolutionary forces driving DNA sequence evolution. Island species usually have lower census population sizes (N) than continental species and, supposedly, lower effective population sizes (Ne). Given that both the rates of change caused by genetic drift and by selection are dependent upon Ne, island species are theoretically expected to exhibit (1) lower genetic diversity, (2) less effective natural selection against slightly deleterious mutations,3,4 and (3) a lower rate of adaptive evolution.5-8 Here, we have used a large set of newly sequenced and published whole-genome sequences of Passerida species (14 insular and 11 continental) to test these predictions. We confirm that island species exhibit lower census size and Ne, supporting the hypothesis that the smaller area available on islands constrains the upper bound of Ne. In the insular species, we find lower nucleotide diversity in coding regions, higher ratios of non-synonymous to synonymous polymorphisms, and lower adaptive substitution rates. Our results provide robust evidence that the lower Ne experienced by island species has affected both the ability of natural selection to efficiently remove weakly deleterious mutations and also the adaptive potential of island species, therefore providing considerable empirical support for the nearly neutral theory. We discuss the implications for both evolutionary and conservation biology.
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Li J, Zhang J, Liu J, Zhou Y, Cai C, Xu L, Dai X, Feng S, Guo C, Rao J, Wei K, Jarvis ED, Jiang Y, Zhou Z, Zhang G, Zhou Q. A new duck genome reveals conserved and convergently evolved chromosome architectures of birds and mammals. Gigascience 2021; 10:giaa142. [PMID: 33406261 PMCID: PMC7787181 DOI: 10.1093/gigascience/giaa142] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2020] [Revised: 10/31/2020] [Accepted: 11/16/2020] [Indexed: 12/29/2022] Open
Abstract
BACKGROUND Ducks have a typical avian karyotype that consists of macro- and microchromosomes, but a pair of much less differentiated ZW sex chromosomes compared to chickens. To elucidate the evolution of chromosome architectures between ducks and chickens, and between birds and mammals, we produced a nearly complete chromosomal assembly of a female Pekin duck by combining long-read sequencing and multiplatform scaffolding techniques. RESULTS A major improvement of genome assembly and annotation quality resulted from the successful resolution of lineage-specific propagated repeats that fragmented the previous Illumina-based assembly. We found that the duck topologically associated domains (TAD) are demarcated by putative binding sites of the insulator protein CTCF, housekeeping genes, or transitions of active/inactive chromatin compartments, indicating conserved mechanisms of spatial chromosome folding with mammals. There are extensive overlaps of TAD boundaries between duck and chicken, and also between the TAD boundaries and chromosome inversion breakpoints. This suggests strong natural selection pressure on maintaining regulatory domain integrity, or vulnerability of TAD boundaries to DNA double-strand breaks. The duck W chromosome retains 2.5-fold more genes relative to chicken. Similar to the independently evolved human Y chromosome, the duck W evolved massive dispersed palindromic structures, and a pattern of sequence divergence with the Z chromosome that reflects stepwise suppression of homologous recombination. CONCLUSIONS Our results provide novel insights into the conserved and convergently evolved chromosome features of birds and mammals, and also importantly add to the genomic resources for poultry studies.
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Affiliation(s)
- Jing Li
- MOE Laboratory of Biosystems Homeostasis & Protection and Zhejiang Provincial Key Laboratory for Cancer Molecular Cell Biology, Life Sciences Institute, Zhejiang University, 866 Yuhangtang Road, Hangzhou 310058, China
| | - Jilin Zhang
- Department of Medical Biochemistry and Biophysics, Karolinska Institutet, 5 Nobels väg, Stockholm 17177, Sweden
| | - Jing Liu
- MOE Laboratory of Biosystems Homeostasis & Protection and Zhejiang Provincial Key Laboratory for Cancer Molecular Cell Biology, Life Sciences Institute, Zhejiang University, 866 Yuhangtang Road, Hangzhou 310058, China
- Department of Neuroscience and Developmental Biology, University of Vienna, 1 Universitätsring, Vienna 1090, Austria
| | - Yang Zhou
- BGI-Shenzhen, 146 Beishan Industrial Zone, Shenzhen 518083, China
| | - Cheng Cai
- MOE Laboratory of Biosystems Homeostasis & Protection and Zhejiang Provincial Key Laboratory for Cancer Molecular Cell Biology, Life Sciences Institute, Zhejiang University, 866 Yuhangtang Road, Hangzhou 310058, China
| | - Luohao Xu
- MOE Laboratory of Biosystems Homeostasis & Protection and Zhejiang Provincial Key Laboratory for Cancer Molecular Cell Biology, Life Sciences Institute, Zhejiang University, 866 Yuhangtang Road, Hangzhou 310058, China
- Department of Neuroscience and Developmental Biology, University of Vienna, 1 Universitätsring, Vienna 1090, Austria
| | - Xuelei Dai
- Key Laboratory of Animal Genetics, Breeding and Reproduction of Shaanxi Province, College of Animal Science and Technology, Northwest A&F University, 3 Taicheng Road, Yangling 712100, China
| | - Shaohong Feng
- BGI-Shenzhen, 146 Beishan Industrial Zone, Shenzhen 518083, China
| | - Chunxue Guo
- BGI-Shenzhen, 146 Beishan Industrial Zone, Shenzhen 518083, China
| | - Jinpeng Rao
- Center for Reproductive Medicine, The 2nd Affiliated Hospital, School of Medicine, Zhejiang University, 88 Jiefang Road, Hangzhou 310052, China
| | - Kai Wei
- Center for Reproductive Medicine, The 2nd Affiliated Hospital, School of Medicine, Zhejiang University, 88 Jiefang Road, Hangzhou 310052, China
| | - Erich D Jarvis
- Laboratory of Neurogenetics of Language, The Rockefeller University, 1230 York Ave, NY 10065, USA
- Howard Hughes Medical Institute, 4000 Jones Bridge Road, Chevy Chase, MD 20815, USA
| | - Yu Jiang
- Key Laboratory of Animal Genetics, Breeding and Reproduction of Shaanxi Province, College of Animal Science and Technology, Northwest A&F University, 3 Taicheng Road, Yangling 712100, China
| | - Zhengkui Zhou
- Institute of Animal Science, Chinese Academy of Agricultural Sciences, 12 Zhong Guan Cun Da Jie, Beijing, China
| | - Guojie Zhang
- China National GeneBank, BGI-Shenzhen, Jinsha Road, Shenzhen 518120, China
- State Key Laboratory of Genetic Resources and Evolution, Kunming Institute of Zoology, Chinese Academy of Sciences, 32 East Jiaochang Road, Kunming 650223, China
- Section for Ecology and Evolution, Department of Biology, University of Copenhagen, 10 Nørregade, DK-2100 Copenhagen, Denmark
- Center for Excellence in Animal Evolution and Genetics, Chinese Academy of Sciences, 32 East Jiaochang Road, Kunming 650223, China
| | - Qi Zhou
- MOE Laboratory of Biosystems Homeostasis & Protection and Zhejiang Provincial Key Laboratory for Cancer Molecular Cell Biology, Life Sciences Institute, Zhejiang University, 866 Yuhangtang Road, Hangzhou 310058, China
- Department of Neuroscience and Developmental Biology, University of Vienna, 1 Universitätsring, Vienna 1090, Austria
- Center for Reproductive Medicine, The 2nd Affiliated Hospital, School of Medicine, Zhejiang University, 88 Jiefang Road, Hangzhou 310052, China
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Zhao Z, Zhou Y, Wang S, Zhang X, Wang C, Li S. LDscaff: LD-based scaffolding of de novo genome assemblies. BMC Bioinformatics 2020; 21:570. [PMID: 33371875 PMCID: PMC7768660 DOI: 10.1186/s12859-020-03895-7] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2020] [Accepted: 11/18/2020] [Indexed: 12/11/2022] Open
Abstract
Background Genome assembly is fundamental for de novo genome analysis. Hybrid assembly, utilizing various sequencing technologies increases both contiguity and accuracy. While such approaches require extra costly sequencing efforts, the information provided millions of existed whole-genome sequencing data have not been fully utilized to resolve the task of scaffolding. Genetic recombination patterns in population data indicate non-random association among alleles at different loci, can provide physical distance signals to guide scaffolding. Results In this paper, we propose LDscaff for draft genome assembly incorporating linkage disequilibrium information in population data. We evaluated the performance of our method with both simulated data and real data. We simulated scaffolds by splitting the pig reference genome and reassembled them. Gaps between scaffolds were introduced ranging from 0 to 100 KB. The genome misassembly rate is 2.43% when there is no gap. Then we implemented our method to refine the Giant Panda genome and the donkey genome, which are purely assembled by NGS data. After LDscaff treatment, the resulting Panda assembly has scaffold N50 of 3.6 MB, 2.5 times larger than the original N50 (1.3 MB). The re-assembled donkey assembly has an improved N50 length of 32.1 MB from 23.8 MB. Conclusions Our method effectively improves the assemblies with existed re-sequencing data, and is an potential alternative to the existing assemblers required for the collection of new data.
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Affiliation(s)
- Zicheng Zhao
- BGI Education Center, University of Chinese Academy of Sciences, Shenzhen, 518083, China.,Department of Computer Science, City University of Hong Kong, Kowloon, Hong Kong SAR, 999077, China
| | - Yingxiao Zhou
- BGI Education Center, University of Chinese Academy of Sciences, Shenzhen, 518083, China.,BGI-Shenzhen, Shenzhen, 518083, China
| | - Shuai Wang
- Department of Computer Science, City University of Hong Kong, Kowloon, Hong Kong SAR, 999077, China
| | - Xiuqing Zhang
- BGI Education Center, University of Chinese Academy of Sciences, Shenzhen, 518083, China
| | - Changfa Wang
- Liaocheng Research Institute of Donkey High-Efficiency Breeding and Ecological Feeding, Liaocheng University, Liaocheng City, 252059, Shandong, China.
| | - Shuaicheng Li
- Department of Computer Science, City University of Hong Kong, Kowloon, Hong Kong SAR, 999077, China.
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Yazdi HP, Silva WTAF, Suh A. Why Do Some Sex Chromosomes Degenerate More Slowly Than Others? The Odd Case of Ratite Sex Chromosomes. Genes (Basel) 2020; 11:E1153. [PMID: 33007827 PMCID: PMC7601716 DOI: 10.3390/genes11101153] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2020] [Revised: 09/25/2020] [Accepted: 09/28/2020] [Indexed: 01/10/2023] Open
Abstract
The hallmark of sex chromosome evolution is the progressive suppression of recombination which leads to subsequent degeneration of the non-recombining chromosome. In birds, species belonging to the two major clades, Palaeognathae (including tinamous and flightless ratites) and Neognathae (all remaining birds), show distinctive patterns of sex chromosome degeneration. Birds are female heterogametic, in which females have a Z and a W chromosome. In Neognathae, the highly-degenerated W chromosome seems to have followed the expected trajectory of sex chromosome evolution. In contrast, among Palaeognathae, sex chromosomes of ratite birds are largely recombining. The underlying reason for maintenance of recombination between sex chromosomes in ratites is not clear. Degeneration of the W chromosome might have halted or slowed down due to a multitude of reasons ranging from selective processes, such as a less pronounced effect of sexually antagonistic selection, to neutral processes, such as a slower rate of molecular evolution in ratites. The production of genome assemblies and gene expression data for species of Palaeognathae has made it possible, during recent years, to have a closer look at their sex chromosome evolution. Here, we critically evaluate the understanding of the maintenance of recombination in ratites in light of the current data. We conclude by highlighting certain aspects of sex chromosome evolution in ratites that require further research and can potentially increase power for the inference of the unique history of sex chromosome evolution in this lineage of birds.
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Affiliation(s)
| | | | - Alexander Suh
- School of Biological Sciences, University of East Anglia, Norwich Research Park, Norwich NR4 7TU, UK;
- Department of Organismal Biology—Systematic Biology, Uppsala University, SE-752 36 Uppsala, Sweden
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The Genomic Landscape of Divergence Across the Speciation Continuum in Island-Colonising Silvereyes ( Zosterops lateralis). G3-GENES GENOMES GENETICS 2020; 10:3147-3163. [PMID: 32660974 PMCID: PMC7466963 DOI: 10.1534/g3.120.401352] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Inferring the evolutionary dynamics at play during the process of speciation by analyzing the genomic landscape of divergence is a major pursuit in population genomics. However, empirical assessments of genomic landscapes under varying evolutionary scenarios that are known a priori are few, thereby limiting our ability to achieve this goal. Here we combine RAD-sequencing and individual-based simulations to evaluate the genomic landscape of divergence in the silvereye (Zosterops lateralis). Using pairwise comparisons that differ in divergence timeframe and the presence or absence of gene flow, we document how genomic patterns accumulate along the speciation continuum. In contrast to previous predictions, our results provide limited support for the idea that divergence accumulates around loci under divergent selection or that genomic islands widen with time. While a small number of genomic islands were found in populations diverging with and without gene flow, in few cases were SNPs putatively under selection tightly associated with genomic islands. The transition from localized to genome-wide levels of divergence was captured using individual-based simulations that considered only neutral processes. Our results challenge the ubiquity of existing verbal models that explain the accumulation of genomic differences across the speciation continuum and instead support the idea that divergence both within and outside of genomic islands is important during the speciation process.
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50
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An 85K SNP Array Uncovers Inbreeding and Cryptic Relatedness in an Antarctic Fur Seal Breeding Colony. G3-GENES GENOMES GENETICS 2020; 10:2787-2799. [PMID: 32540866 PMCID: PMC7407454 DOI: 10.1534/g3.120.401268] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
High density single nucleotide polymorphism (SNP) arrays allow large numbers of individuals to be rapidly and cost-effectively genotyped at large numbers of genetic markers. However, despite being widely used in studies of humans and domesticated plants and animals, SNP arrays are lacking for most wild organisms. We developed a custom 85K Affymetrix Axiom array for an intensively studied pinniped, the Antarctic fur seal (Arctocephalus gazella). SNPs were discovered from a combination of genomic and transcriptomic resources and filtered according to strict criteria. Out of a total of 85,359 SNPs tiled on the array, 75,601 (88.6%) successfully converted and were polymorphic in 270 animals from a breeding colony at Bird Island in South Georgia. Evidence was found for inbreeding, with three genomic inbreeding coefficients being strongly intercorrelated and the proportion of the genome in runs of homozygosity being non-zero in all individuals. Furthermore, analysis of genomic relatedness coefficients identified previously unknown first-degree relatives and multiple second-degree relatives among a sample of ostensibly unrelated individuals. Such “cryptic relatedness” within fur seal breeding colonies may increase the likelihood of consanguineous matings and could therefore have implications for understanding fitness variation and mate choice. Finally, we demonstrate the cross-amplification potential of the array in three related pinniped species. Overall, our SNP array will facilitate future studies of Antarctic fur seals and has the potential to serve as a more general resource for the wider pinniped research community.
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