1
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Potter S, Moritz C, Piggott MP, Bragg JG, Afonso Silva AC, Bi K, McDonald-Spicer C, Turakulov R, Eldridge MDB. Museum Skins Enable Identification of Introgression Associated with Cytonuclear Discordance. Syst Biol 2024; 73:579-593. [PMID: 38577768 PMCID: PMC11377193 DOI: 10.1093/sysbio/syae016] [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: 03/10/2022] [Revised: 03/14/2024] [Accepted: 04/03/2024] [Indexed: 04/06/2024] Open
Abstract
Increased sampling of genomes and populations across closely related species has revealed that levels of genetic exchange during and after speciation are higher than previously thought. One obvious manifestation of such exchange is strong cytonuclear discordance, where the divergence in mitochondrial DNA (mtDNA) differs from that for nuclear genes more (or less) than expected from differences between mtDNA and nuclear DNA (nDNA) in population size and mutation rate. Given genome-scale data sets and coalescent modeling, we can now confidently identify cases of strong discordance and test specifically for historical or recent introgression as the cause. Using population sampling, combining exon capture data from historical museum specimens and recently collected tissues we showcase how genomic tools can resolve complex evolutionary histories in the brachyotis group of rock-wallabies (Petrogale). In particular, applying population and phylogenomic approaches we can assess the role of demographic processes in driving complex evolutionary patterns and assess a role of ancient introgression and hybridization. We find that described species are well supported as monophyletic taxa for nDNA genes, but not for mtDNA, with cytonuclear discordance involving at least 4 operational taxonomic units across 4 species which diverged 183-278 kya. ABC modeling of nDNA gene trees supports introgression during or after speciation for some taxon pairs with cytonuclear discordance. Given substantial differences in body size between the species involved, this evidence for gene flow is surprising. Heterogenous patterns of introgression were identified but do not appear to be associated with chromosome differences between species. These and previous results suggest that dynamic past climates across the monsoonal tropics could have promoted reticulation among related species.
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Affiliation(s)
- Sally Potter
- School of Natural Sciences, 14 Eastern Road, Macquarie University, Macquarie Park, NSW 2109, Australia
- Division of Ecology and Evolution, Research School of Biology, 134 Linnaeus Way, The Australian National University, Acton, ACT 2601, Australia
- Australian Museum Research Institute, Australian Museum, 1 William St, Sydney, NSW 2010, Australia
| | - Craig Moritz
- Division of Ecology and Evolution, Research School of Biology, 134 Linnaeus Way, The Australian National University, Acton, ACT 2601, Australia
| | - Maxine P Piggott
- Division of Ecology and Evolution, Research School of Biology, 134 Linnaeus Way, The Australian National University, Acton, ACT 2601, Australia
- Research Institute for the Environment and Livelihoods, Charles Darwin University, Casuarina, NT 0811, Australia
| | - Jason G Bragg
- National Herbarium of New South Wales, The Royal Botanical Gardens and Domain Trust, Mrs Macquaries Road, Sydney, NSW 2000, Australia
| | | | - Ke Bi
- Museum of Vertebrate Zoology and Department of Integrative Biology, University of California Berkeley, Berkeley, CA 94720, USA
| | - Christiana McDonald-Spicer
- Division of Ecology and Evolution, Research School of Biology, 134 Linnaeus Way, The Australian National University, Acton, ACT 2601, Australia
| | - Rustamzhon Turakulov
- Australian Genome Research Facility, Victorian Comprehensive Cancer Centre, 305 Grattan Street, Melbourne, VIC 3000, Australia
- Earth Sciences, College of Science and Engineering, Flinders University GPO Box 2100, Adelaide, SA 5001, Australia
| | - Mark D B Eldridge
- Australian Museum Research Institute, Australian Museum, 1 William St, Sydney, NSW 2010, Australia
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2
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Augustijnen H, Lucek K. Beyond gene flow: (non)-parallelism of secondary contact in a pair of highly differentiated sibling species. Mol Ecol 2024; 33:e17488. [PMID: 39119885 DOI: 10.1111/mec.17488] [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: 04/02/2024] [Revised: 07/01/2024] [Accepted: 07/10/2024] [Indexed: 08/10/2024]
Abstract
Replicated secondary contact zones can provide insights into the barriers to gene flow that are important during speciation and can reveal to which degree secondary contact may result in similar evolutionary outcomes. Here, we studied two secondary contact zones between highly differentiated Alpine butterflies of the genus Erebia using whole-genome resequencing data. We assessed the genomic relationships between populations and species and found hybridization to be rare, with no to little current or historical introgression in either contact zone. There are large similarities between contact zones, consistent with an allopatric origin of interspecific differentiation, with no indications for ongoing reinforcing selection. Consistent with expected reduced effective population size, we further find that scaffolds related to the Z-chromosome show increased differentiation compared to the already high levels across the entire genome, which could also hint towards a contribution of the Z chromosome to species divergence in this system. Finally, we detected the presence of the endosymbiont Wolbachia, which can cause reproductive isolation between its hosts, in all E. cassioides, while it appears to be fully or largely absent in contact zone populations of E. tyndarus. We discuss how this rare pattern may have arisen and how it may have affected the dynamics of speciation upon secondary contact.
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Affiliation(s)
- Hannah Augustijnen
- Department of Environmental Sciences, University of Basel, Basel, Switzerland
| | - Kay Lucek
- Biodiversity Genomics Laboratory, Institute of Biology, University of Neuchâtel, Neuchâtel, Switzerland
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3
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McFarlane SE, Jahner JP, Lindtke D, Buerkle CA, Mandeville EG. Selection leads to remarkable variability in the outcomes of hybridisation across replicate hybrid zones. Mol Ecol 2024; 33:e17359. [PMID: 38699787 DOI: 10.1111/mec.17359] [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: 09/24/2022] [Revised: 04/03/2024] [Accepted: 04/05/2024] [Indexed: 05/05/2024]
Abstract
Hybrid zones have been viewed as an opportunity to see speciation in action. When hybrid zones are replicated, it is assumed that if the same genetic incompatibilities are maintaining reproductive isolation across all instances of secondary contact, those incompatibilities should be identifiable by consistent patterns in the genome. In contrast, changes in allele frequencies due to genetic drift should be idiosyncratic for each hybrid zone. To test this assumption, we simulated 20 replicates of each of 12 hybrid zone scenarios with varied genetic incompatibilities, rates of migration, selection and different starting population size ratios of parental species. We found remarkable variability in the outcomes of hybridisation in replicate hybrid zones, particularly with Bateson-Dobzhansky-Muller incompatibilities and strong selection. We found substantial differences among replicates in the overall genomic composition of individuals, including admixture proportions, inter-specific ancestry complement and number of ancestry junctions. Additionally, we found substantial variation in genomic clines among replicates at focal loci, regardless of locus-specific selection. We conclude that processes other than selection are responsible for some consistent outcomes of hybridisation, whereas selection on incompatibilities can lead to genomically widespread and highly variable outcomes. We highlight the challenge of mapping between pattern and process in hybrid zones and call attention to how selection against incompatibilities will commonly lead to variable outcomes. We hope that this study informs future research on replicate hybrid zones and encourages further development of statistical techniques, theoretical models and exploration of additional axes of variation to understand reproductive isolation.
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Affiliation(s)
- S Eryn McFarlane
- Department of Botany, University of Wyoming, Laramie, Wyoming, USA
- Department of Biology, York University, Toronto, Ontario, Canada
| | - Joshua P Jahner
- Department of Botany, University of Wyoming, Laramie, Wyoming, USA
| | | | - C Alex Buerkle
- Department of Botany, University of Wyoming, Laramie, Wyoming, USA
| | - Elizabeth G Mandeville
- Department of Integrative Biology, University of Guelph, Guelph, Ontario, Canada
- Biology Department, Northern Michigan University, Marquette, Michigan, USA
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4
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Martins ARP, Warren NB, McMillan WO, Barrett RDH. Spatiotemporal dynamics in butterfly hybrid zones. INSECT SCIENCE 2024; 31:328-353. [PMID: 37596954 DOI: 10.1111/1744-7917.13262] [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: 05/02/2023] [Revised: 07/13/2023] [Accepted: 07/21/2023] [Indexed: 08/21/2023]
Abstract
Evaluating whether hybrid zones are stable or mobile can provide novel insights for evolution and conservation biology. Butterflies exhibit high sensitivity to environmental changes and represent an important model system for the study of hybrid zone origins and maintenance. Here, we review the literature exploring butterfly hybrid zones, with a special focus on their spatiotemporal dynamics and the potential mechanisms that could lead to their movement or stability. We then compare different lines of evidence used to investigate hybrid zone dynamics and discuss the strengths and weaknesses of each approach. Our goal with this review is to reveal general conditions associated with the stability or mobility of butterfly hybrid zones by synthesizing evidence obtained using different types of data sampled across multiple regions and spatial scales. Finally, we discuss spatiotemporal dynamics in the context of a speciation/divergence continuum, the relevance of hybrid zones for conservation biology, and recommend key topics for future investigation.
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Affiliation(s)
- Ananda R Pereira Martins
- Redpath Museum, McGill University, 859 Sherbrooke Street West, Montreal, Quebec, Canada
- Smithsonian Tropical Research Institute, Gamboa, Panama City, Panama
| | - Natalie B Warren
- Redpath Museum, McGill University, 859 Sherbrooke Street West, Montreal, Quebec, Canada
| | - W Owen McMillan
- Smithsonian Tropical Research Institute, Gamboa, Panama City, Panama
| | - Rowan D H Barrett
- Redpath Museum, McGill University, 859 Sherbrooke Street West, Montreal, Quebec, Canada
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5
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Sianta SA, Moeller DA, Brandvain Y. The extent of introgression between incipient Clarkia species is determined by temporal environmental variation and mating system. Proc Natl Acad Sci U S A 2024; 121:e2316008121. [PMID: 38466849 PMCID: PMC10963018 DOI: 10.1073/pnas.2316008121] [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: 09/18/2023] [Accepted: 02/07/2024] [Indexed: 03/13/2024] Open
Abstract
Introgression is pervasive across the tree of life but varies across taxa, geography, and genomic regions. However, the factors modulating this variation and how they may be affected by global change are not well understood. Here, we used 200 genomes and a 15-y site-specific environmental dataset to investigate the effects of environmental variation and mating system divergence on the magnitude of introgression between a recently diverged outcrosser-selfer pair of annual plants in the genus Clarkia. These sister taxa diverged very recently and subsequently came into secondary sympatry where they form replicated contact zones. Consistent with observations of other outcrosser-selfer pairs, we found that introgression was asymmetric between taxa, with substantially more introgression from the selfer to the outcrosser. This asymmetry was caused by a bias in the direction of initial F1 hybrid formation and subsequent backcrossing. We also found extensive variation in the outcrosser's admixture proportion among contact zones, which was predicted nearly entirely by interannual variance in spring precipitation. Greater fluctuations in spring precipitation resulted in higher admixture proportions, likely mediated by the effects of spring precipitation on the expression of traits that determine premating reproductive isolation. Climate-driven hybridization dynamics may be particularly affected by global change, potentially reshaping species boundaries and adaptation to novel environments.
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Affiliation(s)
- Shelley A. Sianta
- Department of Plant and Microbial Biology, University of Minnesota, St. Paul, MN55108
| | - David A. Moeller
- Department of Plant and Microbial Biology, University of Minnesota, St. Paul, MN55108
| | - Yaniv Brandvain
- Department of Plant and Microbial Biology, University of Minnesota, St. Paul, MN55108
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6
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Stone BW, Wessinger CA. Ecological Diversification in an Adaptive Radiation of Plants: The Role of De Novo Mutation and Introgression. Mol Biol Evol 2024; 41:msae007. [PMID: 38232726 PMCID: PMC10826641 DOI: 10.1093/molbev/msae007] [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: 11/01/2023] [Revised: 01/01/2024] [Accepted: 01/10/2024] [Indexed: 01/19/2024] Open
Abstract
Adaptive radiations are characterized by rapid ecological diversification and speciation events, leading to fuzzy species boundaries between ecologically differentiated species. Adaptive radiations are therefore key systems for understanding how species are formed and maintained, including the role of de novo mutations versus preexisting variation in ecological adaptation and the genome-wide consequences of hybridization events. For example, adaptive introgression, where beneficial alleles are transferred between lineages through hybridization, may fuel diversification in adaptive radiations and facilitate adaptation to new environments. In this study, we employed whole-genome resequencing data to investigate the evolutionary origin of hummingbird-pollinated flowers and to characterize genome-wide patterns of phylogenetic discordance and introgression in Penstemon subgenus Dasanthera, a small and diverse adaptive radiation of plants. We found that magenta hummingbird-adapted flowers have apparently evolved twice from ancestral blue-violet bee-pollinated flowers within this radiation. These shifts in flower color are accompanied by a variety of inactivating mutations to a key anthocyanin pathway enzyme, suggesting that independent de novo loss-of-function mutations underlie the parallel evolution of this trait. Although patterns of introgression and phylogenetic discordance were heterogenous across the genome, a strong effect of gene density suggests that, in general, natural selection opposes introgression and maintains genetic differentiation in gene-rich genomic regions. Our results highlight the importance of both de novo mutation and introgression as sources of evolutionary change and indicate a role for de novo mutation in driving parallel evolution in adaptive radiations.
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Affiliation(s)
- Benjamin W Stone
- Department of Biological Sciences, University of South Carolina, Columbia, SC 29208-3401, USA
| | - Carolyn A Wessinger
- Department of Biological Sciences, University of South Carolina, Columbia, SC 29208-3401, USA
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7
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Stone BW, Wessinger CA. Ecological diversification in an adaptive radiation of plants: the role of de novo mutation and introgression. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2023.11.01.565185. [PMID: 37961506 PMCID: PMC10635055 DOI: 10.1101/2023.11.01.565185] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/15/2023]
Abstract
Adaptive radiations are characterized by rapid ecological diversification and speciation events, leading to fuzzy species boundaries between ecologically differentiated species. Adaptive radiations are therefore key systems for understanding how species are formed and maintained, including the role of de novo mutations vs. pre-existing variation in ecological adaptation and the genome-wide consequences of hybridization events. For example, adaptive introgression, where beneficial alleles are transferred between lineages through hybridization, may fuel diversification in adaptive radiations and facilitate adaptation to new environments. In this study, we employed whole-genome resequencing data to investigate the evolutionary origin of hummingbird-pollinated flowers and to characterize genome-wide patterns of phylogenetic discordance and introgression in Penstemon subgenus Dasanthera, a small and diverse adaptive radiation of plants. We found that magenta hummingbird-adapted flowers have apparently evolved twice from ancestral blue-violet bee-pollinated flowers within this radiation. These shifts in flower color are accompanied by a variety of inactivating mutations to a key anthocyanin pathway enzyme, suggesting that independent de novo loss-of-function mutations underlie parallel evolution of this trait. Although patterns of introgression and phylogenetic discordance were heterogenous across the genome, a strong effect of gene density suggests that, in general, natural selection opposes introgression and maintains genetic differentiation in gene-rich genomic regions. Our results highlight the importance of both de novo mutation and introgression as sources of evolutionary change and indicate a role for de novo mutation in driving parallel evolution in adaptive radiations.
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Affiliation(s)
- Benjamin W. Stone
- Department of Biological Sciences, University of South Carolina, Columbia, SC 29208-3401, USA
| | - Carolyn A. Wessinger
- Department of Biological Sciences, University of South Carolina, Columbia, SC 29208-3401, USA
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8
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Farleigh K, Ascanio A, Farleigh ME, Schield DR, Card DC, Leal M, Castoe TA, Jezkova T, Rodríguez-Robles JA. Signals of differential introgression in the genome of natural hybrids of Caribbean anoles. Mol Ecol 2023; 32:6000-6017. [PMID: 37861454 DOI: 10.1111/mec.17170] [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: 12/28/2021] [Revised: 08/30/2023] [Accepted: 10/03/2023] [Indexed: 10/21/2023]
Abstract
Hybridization facilitates recombination between divergent genetic lineages and can be shaped by both neutral and selective processes. Upon hybridization, loci with no net fitness effects introgress randomly from parental species into the genomes of hybrid individuals. Conversely, alleles from one parental species at some loci may provide a selective advantage to hybrids, resulting in patterns of introgression that do not conform to random expectations. We investigated genomic patterns of differential introgression in natural hybrids of two species of Caribbean anoles, Anolis pulchellus and A. krugi in Puerto Rico. Hybrids exhibit A. pulchellus phenotypes but possess A. krugi mitochondrial DNA, originated from multiple, independent hybridization events, and appear to have replaced pure A. pulchellus across a large area in western Puerto Rico. Combining genome-wide SNP datasets with bioinformatic methods to identify signals of differential introgression in hybrids, we demonstrate that the genomes of hybrids are dominated by pulchellus-derived alleles and show only 10%-20% A. krugi ancestry. The majority of A. krugi loci in hybrids exhibit a signal of non-random differential introgression and include loci linked to genes involved in development and immune function. Three of these genes (delta like canonical notch ligand 1, jagged1 and notch receptor 1) affect cell differentiation and growth and interact with mitochondrial function. Our results suggest that differential non-random introgression for a subset of loci may be driven by selection favouring the inheritance of compatible mitochondrial and nuclear-encoded genes in hybrids.
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Affiliation(s)
- Keaka Farleigh
- Department of Biology, Miami University, Oxford, Ohio, USA
| | | | | | - Drew R Schield
- Department of Ecology and Evolutionary Biology, University of Colorado, Boulder, Colorado, USA
| | - Daren C Card
- Department of Organismic and Evolutionary Biology, Harvard University, Cambridge, Massachusetts, USA
- Museum of Comparative Zoology, Harvard University, Cambridge, Massachusetts, USA
| | - Manuel Leal
- Division of Biological Sciences, University of Missouri, Columbia, Missouri, USA
| | - Todd A Castoe
- Department of Biology, University of Texas, Arlington, Arlington, Texas, USA
| | - Tereza Jezkova
- Department of Biology, Miami University, Oxford, Ohio, USA
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9
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Giakoumis M, Pinilla-Buitrago GE, Musher LJ, Wares JP, Baird SJE, Hickerson MJ. Evidence of introgression, ecological divergence and adaptation in Asterias sea stars. Mol Ecol 2023; 32:5541-5557. [PMID: 37691604 DOI: 10.1111/mec.17118] [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: 06/24/2022] [Revised: 07/29/2023] [Accepted: 08/09/2023] [Indexed: 09/12/2023]
Abstract
Hybrid zones are important windows into the evolutionary dynamics of populations, revealing how processes like introgression and adaptation structure population genomic variation. Importantly, they are useful for understanding speciation and how species respond to their environments. Here, we investigate two closely related sea star species, Asterias rubens and A. forbesi, distributed along rocky European and North American coastlines of the North Atlantic, and use genome-wide molecular markers to infer the distribution of genomic variation within and between species in this group. Using genomic data and environmental niche modelling, we document hybridization occurring between northern New England and the southern Canadian Maritimes. We investigate the factors that maintain this hybrid zone, as well as the environmental variables that putatively drive selection within and between species. We find that the two species differ in their environmental niche breadth; Asterias forbesi displays a relatively narrow environmental niche while conversely, A. rubens has a wider niche breadth. Species distribution models accurately predict hybrids to occur within environmental niche overlap, thereby suggesting environmental selection plays an important role in the maintenance of the hybrid zone. Our results imply that the distribution of genomic variation in North Atlantic sea stars is influenced by the environment, which will be crucial to consider as the climate changes.
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Affiliation(s)
- Melina Giakoumis
- The Graduate Center, The City University of New York, New York, New York City, USA
- The City College of New York, New York, New York City, USA
- The American Museum of Natural History, New York, New York City, USA
| | - Gonzalo E Pinilla-Buitrago
- The Graduate Center, The City University of New York, New York, New York City, USA
- The City College of New York, New York, New York City, USA
| | - Lukas J Musher
- The Academy of Natural Sciences of Drexel University, Pennsylvania, Philadelphia, USA
| | - John P Wares
- Odum School of Ecology and Department of Genetics, University of Georgia, Georgia, Athens, USA
| | - Stuart J E Baird
- Institute of Vertebrate Biology, Czech Academy of Sciences, Brno, Czechia
| | - Michael J Hickerson
- The Graduate Center, The City University of New York, New York, New York City, USA
- The City College of New York, New York, New York City, USA
- The American Museum of Natural History, New York, New York City, USA
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10
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Duvernell DD, Remex NS, Miller JT, Schaefer JF. Variable rates of hybridization among contact zones between a pair of topminnow species, Fundulus notatus and F. olivaceus. Ecol Evol 2023; 13:e10399. [PMID: 37560181 PMCID: PMC10408002 DOI: 10.1002/ece3.10399] [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: 07/19/2023] [Accepted: 07/21/2023] [Indexed: 08/11/2023] Open
Abstract
Pairs of species that exhibit broadly overlapping distributions, and multiple geographically isolated contact zones, provide opportunities to investigate the mechanisms of reproductive isolation. Such naturally replicated systems have demonstrated that hybridization rates can vary substantially among populations, raising important questions about the genetic basis of reproductive isolation. The topminnows, Fundulus notatus and F. olivaceus, are reciprocally monophyletic, and co-occur in drainages throughout much of the central and southern United States. Hybridization rates vary substantially among populations in isolated drainage systems. We employed genome-wide sampling to investigate geographic variation in hybridization, and to assess the possible importance of chromosome fusions to reproductive isolation among nine separate contact zones. The species differ by chromosomal rearrangements resulting from Robertsonian (Rb) fusions, so we hypothesized that Rb fusion chromosomes would serve as reproductive barriers, exhibiting steeper genomic clines than the rest of the genome. We observed variation in hybridization dynamics among drainages that ranged from nearly random mating to complete absence of hybridization. Contrary to predictions, our use of genomic cline analyses on mapped species-diagnostic SNP markers did not indicate consistent patterns of variable introgression across linkage groups, or an association between Rb fusions and genomic clines that would be indicative of reproductive isolation. We did observe a relationship between hybridization rates and population phylogeography, with the lowest rates of hybridization tending to be found in populations inferred to have had the longest histories of drainage sympatry. Our results, combined with previous studies of contact zones between the species, support population history as an important factor in explaining variation in hybridization rates.
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Affiliation(s)
- David D. Duvernell
- Department of Biological SciencesMissouri University of Science and TechnologyRollaMissouriUSA
| | - Naznin S. Remex
- Department of Biological SciencesMissouri University of Science and TechnologyRollaMissouriUSA
- Present address:
Department of Molecular and Cellular PhysiologyLouisiana State University Health Sciences CenterShreveportLouisianaUSA
| | - Jeffrey T. Miller
- Molecular, Cellular, and Biomedical SciencesUniversity of New HampshireDurhamNew HampshireUSA
| | - Jacob F. Schaefer
- Department of Biological SciencesUniversity of Southern MississippiHattiesburgMississippiUSA
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11
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Shang H, Field DL, Paun O, Rendón-Anaya M, Hess J, Vogl C, Liu J, Ingvarsson PK, Lexer C, Leroy T. Drivers of genomic landscapes of differentiation across a Populus divergence gradient. Mol Ecol 2023; 32:4348-4361. [PMID: 37271855 DOI: 10.1111/mec.17034] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2023] [Revised: 04/20/2023] [Accepted: 05/23/2023] [Indexed: 06/06/2023]
Abstract
Speciation, the continuous process by which new species form, is often investigated by looking at the variation of nucleotide diversity and differentiation across the genome (hereafter genomic landscapes). A key challenge lies in how to determine the main evolutionary forces at play shaping these patterns. One promising strategy, albeit little used to date, is to comparatively investigate these genomic landscapes as progression through time by using a series of species pairs along a divergence gradient. Here, we resequenced 201 whole-genomes from eight closely related Populus species, with pairs of species at different stages along the divergence gradient to learn more about speciation processes. Using population structure and ancestry analyses, we document extensive introgression between some species pairs, especially those with parapatric distributions. We further investigate genomic landscapes, focusing on within-species (i.e. nucleotide diversity and recombination rate) and among-species (i.e. relative and absolute divergence) summary statistics of diversity and divergence. We observe relatively conserved patterns of genomic divergence across species pairs. Independent of the stage across the divergence gradient, we find support for signatures of linked selection (i.e. the interaction between natural selection and genetic linkage) in shaping these genomic landscapes, along with gene flow and standing genetic variation. We highlight the importance of investigating genomic patterns on multiple species across a divergence gradient and discuss prospects to better understand the evolutionary forces shaping the genomic landscapes of diversity and differentiation.
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Affiliation(s)
- Huiying Shang
- Department of Botany and Biodiversity Research, University of Vienna, Vienna, Austria
- Vienna Graduate School of Population Genetics, Vienna, Austria
- Xi'an Botanical Garden of Shaanxi Province, Institute of Botany of Shaanxi Province, Xi'an, China
| | - David L Field
- School of Science, Edith Cowan University, Joondalup, Western Australia, Australia
| | - Ovidiu Paun
- Department of Botany and Biodiversity Research, University of Vienna, Vienna, Austria
| | - Martha Rendón-Anaya
- Department of Plant Biology, Swedish University of Agricultural Sciences (SLU), Uppsala, Sweden
| | - Jaqueline Hess
- Helmholtz Centre for Environmental Research, Halle (Saale), Germany
| | - Claus Vogl
- Department of Biomedical Sciences, Vetmeduni Vienna, Vienna, Austria
| | - Jianquan Liu
- Key Laboratory for Bio-resources and Eco-environment, College of Life Science, Sichuan University, Chengdu, China
| | - Pär K Ingvarsson
- Department of Plant Biology, Swedish University of Agricultural Sciences (SLU), Uppsala, Sweden
| | - Christian Lexer
- Department of Botany and Biodiversity Research, University of Vienna, Vienna, Austria
| | - Thibault Leroy
- Department of Botany and Biodiversity Research, University of Vienna, Vienna, Austria
- GenPhySE, INRAE, INP, ENVT, Université de Toulouse, Castanet-Tolosan, France
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12
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van Riemsdijk I, Arntzen JW, Bucciarelli GM, McCartney-Melstad E, Rafajlović M, Scott PA, Toffelmier E, Shaffer HB, Wielstra B. Two transects reveal remarkable variation in gene flow on opposite ends of a European toad hybrid zone. Heredity (Edinb) 2023; 131:15-24. [PMID: 37106116 PMCID: PMC10313803 DOI: 10.1038/s41437-023-00617-6] [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: 06/06/2022] [Revised: 03/27/2023] [Accepted: 04/12/2023] [Indexed: 04/29/2023] Open
Abstract
Speciation entails a reduction in gene flow between lineages. The rates at which genomic regions become isolated varies across space and time. Barrier markers are linked to putative genes involved in (processes of) reproductive isolation, and, when observed over two transects, indicate species-wide processes. In contrast, transect-specific putative barrier markers suggest local processes. We studied two widely separated transects along the 900 km hybrid zone between Bufo bufo and B. spinosus, in northern and southern France, for ~1200 RADseq markers. We used genomic and geographic cline analyses to identify barrier markers based on their restricted introgression, and found that some markers are transect-specific, while others are shared between transects. Twenty-six barrier markers were shared across both transects, of which some are clustered in the same chromosomal region, suggesting that their associated genes are involved in reduced gene flow across the entire hybrid zone. Transect-specific barrier markers were twice as numerous in the southern than in the northern transect, suggesting that the overall barrier effect is weaker in northern France. We hypothesize that this is consistent with a longer period of secondary contact in southern France. The smaller number of introgressed genes in the northern transect shows considerably more gene flow towards the southern (B. spinosus) than the northern species (B. bufo). We hypothesize that hybrid zone movement in northern France and hybrid zone stability in southern France explain this pattern. The Bufo hybrid zone provides an excellent opportunity to separate a general barrier effect from localized gene flow-reducing conditions.
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Affiliation(s)
- I van Riemsdijk
- Naturalis Biodiversity Center, Leiden, the Netherlands.
- Institute of Biology Leiden, Leiden University, Leiden, the Netherlands.
- Institute for Evolution and Ecology, Plant Evolutionary Ecology, Tübingen University, Tübingen, Germany.
| | - J W Arntzen
- Naturalis Biodiversity Center, Leiden, the Netherlands
- Institute of Biology Leiden, Leiden University, Leiden, the Netherlands
| | - G M Bucciarelli
- Department of Ecology and Evolutionary Biology, UCLA, Los Angeles, CA, USA
- La Kretz Center for California Conservation Science, Institute of the Environment and Sustainability, UCLA, Los Angeles, CA, USA
- Institute of the Environment, UC Davis, Davis, CA, USA
- Department of Wildlife, Fish, and Conservation Biology, UC Davis, Davis, CA, USA
| | - E McCartney-Melstad
- Department of Ecology and Evolutionary Biology, UCLA, Los Angeles, CA, USA
- La Kretz Center for California Conservation Science, Institute of the Environment and Sustainability, UCLA, Los Angeles, CA, USA
| | - M Rafajlović
- Department of Marine Sciences, University of Gothenburg, Gothenburg, Sweden
- The Linnaeus Centre for Marine Evolutionary Biology, University of Gothenburg, Gothenburg, Sweden
| | - P A Scott
- Department of Ecology and Evolutionary Biology, UCLA, Los Angeles, CA, USA
- Natural Sciences Collegium, Eckerd College, 4200 54 Ave S, St Petersburg, FL, 33711, USA
| | - E Toffelmier
- Department of Ecology and Evolutionary Biology, UCLA, Los Angeles, CA, USA
- La Kretz Center for California Conservation Science, Institute of the Environment and Sustainability, UCLA, Los Angeles, CA, USA
| | - H B Shaffer
- Department of Ecology and Evolutionary Biology, UCLA, Los Angeles, CA, USA
- La Kretz Center for California Conservation Science, Institute of the Environment and Sustainability, UCLA, Los Angeles, CA, USA
| | - B Wielstra
- Naturalis Biodiversity Center, Leiden, the Netherlands
- Institute of Biology Leiden, Leiden University, Leiden, the Netherlands
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13
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Tukhbatullin A, Ermakov O, Kapustina S, Starikov V, Tambovtseva V, Titov S, Brandler O. Surrounded by Kindred: Spermophilus major Hybridization with Other Spermophilus Species in Space and Time. BIOLOGY 2023; 12:880. [PMID: 37372163 DOI: 10.3390/biology12060880] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/17/2023] [Revised: 06/05/2023] [Accepted: 06/15/2023] [Indexed: 06/29/2023]
Abstract
Among the numerous described cases of hybridization in mammals, the most intriguing are (a) cases of introgressive hybridization deeply affecting the evolutionary history of species, and (b) models involving not a pair of species but a multi-species complex. Therefore, the hybridization history of the russet ground squirrel Spermophilus major, whose range has repeatedly changed due to climatic fluctuations and now borders the ranges of four related species, is of great interest. The main aims of this study were to determine the direction and intensity of gene introgression, the spatial depth of the infiltration of extraneous genes into the S. major range, and to refine the hypothesis of the hybridogenic replacement of mitochondrial genomes in the studied group. Using phylogenetic analysis of the variability of mitochondrial (CR, cytb) and nuclear (SmcY, BGN, PRKCI, c-myc, i6p53) markers, we determined the contribution of neighboring species to the S. major genome. We showed that 36% of S. major individuals had extraneous alleles. All peripheral species that were in contact with S. major contributed towards its genetic variability. We also proposed a hypothesis for the sequence and localization of serial hybridization events. Our assessment of the S. major genome implications of introgression highlights the importance of implementing conservation measures to protect this species.
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Affiliation(s)
- Andrey Tukhbatullin
- Koltzov Institute of Developmental Biology, Russian Academy of Sciences, Vavilova Str. 26, Moscow 119334, Russia
| | - Oleg Ermakov
- Faculty of Physics, Mathematics and Natural Sciences, Belinsky Institute of Teacher Education, Penza State University, Lermontov Str. 37, Penza 440026, Russia
| | - Svetlana Kapustina
- Koltzov Institute of Developmental Biology, Russian Academy of Sciences, Vavilova Str. 26, Moscow 119334, Russia
| | - Vladimir Starikov
- Department of Biology and Biotechnology, Institute of Natural and Technical Sciences, Surgut State University, Lenin Avenue 1, Surgut 628412, Russia
| | - Valentina Tambovtseva
- Koltzov Institute of Developmental Biology, Russian Academy of Sciences, Vavilova Str. 26, Moscow 119334, Russia
| | - Sergey Titov
- Faculty of Physics, Mathematics and Natural Sciences, Belinsky Institute of Teacher Education, Penza State University, Lermontov Str. 37, Penza 440026, Russia
| | - Oleg Brandler
- Koltzov Institute of Developmental Biology, Russian Academy of Sciences, Vavilova Str. 26, Moscow 119334, Russia
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14
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Benites P, Zaldívar-Riverón A, Meza-Lázaro RN, Samacá-Sáenz E, Gutiérrez-Rodríguez J, Hernández-López A. Multiple introgression events during the diversification history of the edible mexican grasshopper genus sphenarium (orthoptera: pyrgomorphidae). Mol Phylogenet Evol 2023; 183:107774. [PMID: 36972795 DOI: 10.1016/j.ympev.2023.107774] [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: 11/05/2022] [Revised: 03/07/2023] [Accepted: 03/22/2023] [Indexed: 03/29/2023]
Abstract
Speciation with gene flow often leads to ambiguous phylogenetic reconstructions, reticulate patterns of relatedness and conflicting nuclear versus mitochondrial (mt) lineages. Here we employed a fragment of the COI mtDNA gene and nuclear genome-wide data (3RAD) to assess the diversification history of Sphenarium, an orthopteran genus of great economic importance in Mexico that is presumed to have experienced hybridisation events in some of its species. We carried out separate phylogenetic analyses to evaluate the existence of mito-nuclear discordance in the species relationships, and also assessed the genomic diversity and population genomic structure and investigated the existence of interspecific introgression and species limits of the taxa involved based on the nuclear dataset. The species delineation analyses discriminated all the currently recognised species, but also supported the existence of four undescribed species. The mt and nuclear topologies had four discordant species relationships that can be explained by mt introgression, where the mt haplotypes of S. purpurascens appear to have replaced those of S. purpurascens A and B, S. variabile and S. zapotecum. Moreover, our analyses supported the existence of nuclear introgression events between four species pairs that are distributed in the Sierra Madre del Sur province in southeast Mexico, with three of them occurring in the Tehuantepec Isthmus region. Our study highlights the relevance of genomic data to address the relative importance of allopatric isolation versus gene flow in speciation.
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Affiliation(s)
- Pilar Benites
- Colección Nacional de Insectos, Instituto de Biología, Universidad Nacional Autónoma de México, 3er Circuito Exterior s/n, Cd. Universitaria, Copilco, Coyoacán, A. P. 70-233, C. P. 04510, Ciudad de México, México
| | - Alejandro Zaldívar-Riverón
- Colección Nacional de Insectos, Instituto de Biología, Universidad Nacional Autónoma de México, 3er Circuito Exterior s/n, Cd. Universitaria, Copilco, Coyoacán, A. P. 70-233, C. P. 04510, Ciudad de México, México
| | - Rubi N Meza-Lázaro
- Colección Nacional de Insectos, Instituto de Biología, Universidad Nacional Autónoma de México, 3er Circuito Exterior s/n, Cd. Universitaria, Copilco, Coyoacán, A. P. 70-233, C. P. 04510, Ciudad de México, México
| | - Ernesto Samacá-Sáenz
- Colección Nacional de Insectos, Instituto de Biología, Universidad Nacional Autónoma de México, 3er Circuito Exterior s/n, Cd. Universitaria, Copilco, Coyoacán, A. P. 70-233, C. P. 04510, Ciudad de México, México; Instituto de Investigaciones Biomédicas, Departamento de Biología Celular y Fisiología, Universidad Nacional Autónoma de México, 3er Circuito Exterior s/n, Cd. Universitaria, Coyoacán, 04510 Ciudad de México, México
| | | | - Antonio Hernández-López
- Escuela Nacional de Estudios Superiores Unidad León, Universidad Nacional Autónoma de México, Guanajuato, México
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15
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Eliason CM, Cooper JC, Hackett SJ, Zahnle E, Pequeño Saco TZ, Maddox JD, Hains T, Hauber ME, Bates JM. Interspecific hybridization explains rapid gorget colour divergence in Heliodoxa hummingbirds (Aves: Trochilidae). ROYAL SOCIETY OPEN SCIENCE 2023; 10:221603. [PMID: 36866078 PMCID: PMC9974296 DOI: 10.1098/rsos.221603] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 05/12/2021] [Accepted: 01/26/2023] [Indexed: 06/18/2023]
Abstract
Hybridization is a known source of morphological, functional and communicative signal novelty in many organisms. Although diverse mechanisms of established novel ornamentation have been identified in natural populations, we lack an understanding of hybridization effects across levels of biological scales and upon phylogenies. Hummingbirds display diverse structural colours resulting from coherent light scattering by feather nanostructures. Given the complex relationship between feather nanostructures and the colours they produce, intermediate coloration does not necessarily imply intermediate nanostructures. Here, we characterize nanostructural, ecological and genetic inputs in a distinctive Heliodoxa hummingbird from the foothills of eastern Peru. Genetically, this individual is closely allied with Heliodoxa branickii and Heliodoxa gularis, but it is not identical to either when nuclear data are assessed. Elevated interspecific heterozygosity further suggests it is a hybrid backcross to H. branickii. Electron microscopy and spectrophotometry of this unique individual reveal key nanostructural differences underlying its distinct gorget colour, confirmed by optical modelling. Phylogenetic comparative analysis suggests that the observed gorget coloration divergence from both parentals to this individual would take 6.6-10 My to evolve at the current rate within a single hummingbird lineage. These results emphasize the mosaic nature of hybridization and suggest that hybridization may contribute to the structural colour diversity found across hummingbirds.
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Affiliation(s)
- Chad M. Eliason
- Negaunee Integrative Research Center, Field Museum of Natural History, 1400 S Lake Shore Drive, Chicago, IL 60605, USA
- Grainger Bioinformatics Center, Field Museum of Natural History, 1400 S Lake Shore Drive, Chicago, IL 60605, USA
| | - Jacob C. Cooper
- Negaunee Integrative Research Center, Field Museum of Natural History, 1400 S Lake Shore Drive, Chicago, IL 60605, USA
- Biodiversity Institute, University of Kansas, 1345 Jayhawk Boulevard, Lawrence, KS 66044, USA
- Directora de Monitoreo y Evaluacion de Recursos Naturales del Territorio, Plataforma digital única del Estado Peruano, Iquitos, Perú
| | - Shannon J. Hackett
- Negaunee Integrative Research Center, Field Museum of Natural History, 1400 S Lake Shore Drive, Chicago, IL 60605, USA
- Pritzker Laboratory for Molecular Systematics and Evolution, Field Museum of Natural History, 1400 S Lake Shore Drive, Chicago, IL 60605, USA
| | - Erica Zahnle
- Biodiversity Institute, University of Kansas, 1345 Jayhawk Boulevard, Lawrence, KS 66044, USA
| | - Tatiana Z. Pequeño Saco
- Laboratorio de Biotecnología y Bioenergética, Universidad Científica del Perú, Iquitos, Perú
| | - Joseph Dylan Maddox
- Pritzker Laboratory for Molecular Systematics and Evolution, Field Museum of Natural History, 1400 S Lake Shore Drive, Chicago, IL 60605, USA
- Laboratorio de Biotecnología y Bioenergética, Universidad Científica del Perú, Iquitos, Perú
| | - Taylor Hains
- Negaunee Integrative Research Center, Field Museum of Natural History, 1400 S Lake Shore Drive, Chicago, IL 60605, USA
- Pritzker Laboratory for Molecular Systematics and Evolution, Field Museum of Natural History, 1400 S Lake Shore Drive, Chicago, IL 60605, USA
| | - Mark E. Hauber
- Department of Evolution, Ecology, and Behaviour, School at Integrative Biology, University of Illinois, Urbana-Champaign, IL 61801, USA
| | - John M. Bates
- Negaunee Integrative Research Center, Field Museum of Natural History, 1400 S Lake Shore Drive, Chicago, IL 60605, USA
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16
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Walsh J, Billerman SM, Butcher BG, Rohwer VG, Toews DPL, Vila-Coury V, Lovette IJ. A complex genomic architecture underlies reproductive isolation in a North American oriole hybrid zone. Commun Biol 2023; 6:154. [PMID: 36747071 PMCID: PMC9902562 DOI: 10.1038/s42003-023-04532-8] [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: 02/15/2022] [Accepted: 01/26/2023] [Indexed: 02/08/2023] Open
Abstract
Natural hybrid zones provide powerful opportunities for identifying the mechanisms that facilitate and inhibit speciation. Documenting the extent of genomic admixture allows us to discern the architecture of reproductive isolation through the identification of isolating barriers. This approach is particularly powerful for characterizing the accumulation of isolating barriers in systems exhibiting varying levels of genomic divergence. Here, we use a hybrid zone between two species-the Baltimore (Icterus galbula) and Bullock's (I. bullockii) orioles-to investigate this architecture of reproductive isolation. We combine whole genome re-sequencing with data from an additional 313 individuals amplityped at ancestry-informative markers to characterize fine-scale patterns of admixture, and to quantify links between genes and the plumage traits. On a genome-wide scale, we document several putative barriers to reproduction, including elevated peaks of divergence above a generally high genomic baseline, a large putative inversion on the Z chromosome, and complex interactions between melanogenesis-pathway candidate genes. Concordant and coincident clines for these different genomic regions further suggest the coupling of pre- and post-mating barriers. Our findings of complex and coupled interactions between pre- and post-mating barriers suggest a relatively rapid accumulation of barriers between these species, and they demonstrate the complexities of the speciation process.
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Affiliation(s)
- Jennifer Walsh
- Fuller Evolutionary Biology Program, Cornell Lab of Ornithology, Cornell University, Ithaca, NY, USA.
| | - Shawn M Billerman
- Fuller Evolutionary Biology Program, Cornell Lab of Ornithology, Cornell University, Ithaca, NY, USA
| | - Bronwyn G Butcher
- Fuller Evolutionary Biology Program, Cornell Lab of Ornithology, Cornell University, Ithaca, NY, USA
| | - Vanya G Rohwer
- Fuller Evolutionary Biology Program, Cornell Lab of Ornithology, Cornell University, Ithaca, NY, USA
| | - David P L Toews
- Department of Biology, Penn State University, University Park, Pennsylvania, USA
| | - Vicens Vila-Coury
- Fuller Evolutionary Biology Program, Cornell Lab of Ornithology, Cornell University, Ithaca, NY, USA
| | - Irby J Lovette
- Fuller Evolutionary Biology Program, Cornell Lab of Ornithology, Cornell University, Ithaca, NY, USA
- Department of Ecology and Evolutionary Biology, Cornell University, Ithaca, NY, USA
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17
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Lapègue S, Reisser C, Harrang E, Heurtebise S, Bierne N. Genetic parallelism between European flat oyster populations at the edge of their natural range. Evol Appl 2023; 16:393-407. [PMID: 36793680 PMCID: PMC9923475 DOI: 10.1111/eva.13449] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2022] [Revised: 07/07/2022] [Accepted: 07/11/2022] [Indexed: 11/28/2022] Open
Abstract
Although all marine ecosystems have experienced global-scale losses, oyster reefs have shown the greatest. Therefore, substantial efforts have been dedicated to restoration of such ecosystems during the last two decades. In Europe, several pilot projects for the restoration of the native European flat oyster, Ostrea edulis, recently begun and recommendations to preserve genetic diversity and to conduct monitoring protocols have been made. In particular, an initial step is to test for genetic differentiation against homogeneity among the oyster populations potentially involved in such programs. Therefore, we conducted a new sampling of wild populations at the European scale and a new genetic analysis with 203 markers to (1) confirm and study in more detail the pattern of genetic differentiation between Atlantic and Mediterranean populations, (2) identify potential translocations that could be due to aquaculture practices and (3) investigate the populations at the fringe of the geographical range, since they seemed related despite their geographic distance. Such information should be useful to enlighten the choice of the animals to be translocated or reproduced in hatcheries for further restocking. After the confirmation of the general geographical pattern of genetic structure and the identification of one potential case of aquaculture transfer at a large scale, we were able to detect genomic islands of differentiation mainly in the form of two groups of linked markers, which could indicate the presence of polymorphic chromosomal rearrangements. Furthermore, we observed a tendency for these two islands and the most differentiated loci to show a parallel pattern of differentiation, grouping the North Sea populations with the Eastern Mediterranean and Black Sea populations, against geography. We discussed the hypothesis that this genetic parallelism could be the sign of a shared evolutionary history of the two groups of populations despite them being at the border of the distribution nowadays.
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Affiliation(s)
- Sylvie Lapègue
- MARBEC, Univ Montpellier, CNRSIfremer, IRDMontpellierFrance
| | - Céline Reisser
- MARBEC, Univ Montpellier, CNRSIfremer, IRDMontpellierFrance
| | | | | | - Nicolas Bierne
- ISEM, Univ Montpellier, CNRS, EPHE, IRDMontpellierFrance
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18
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Matias AMA, Popovic I, Thia JA, Cooke IR, Torda G, Lukoschek V, Bay LK, Kim SW, Riginos C. Cryptic diversity and spatial genetic variation in the coral Acropora tenuis and its endosymbionts across the Great Barrier Reef. Evol Appl 2023; 16:293-310. [PMID: 36793689 PMCID: PMC9923489 DOI: 10.1111/eva.13435] [Citation(s) in RCA: 9] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2022] [Revised: 05/20/2022] [Accepted: 05/29/2022] [Indexed: 11/26/2022] Open
Abstract
Genomic studies are uncovering extensive cryptic diversity within reef-building corals, suggesting that evolutionarily and ecologically relevant diversity is highly underestimated in the very organisms that structure coral reefs. Furthermore, endosymbiotic algae within coral host species can confer adaptive responses to environmental stress and may represent additional axes of coral genetic variation that are not constrained by taxonomic divergence of the cnidarian host. Here, we examine genetic variation in a common and widespread, reef-building coral, Acropora tenuis, and its associated endosymbiotic algae along the entire expanse of the Great Barrier Reef (GBR). We use SNPs derived from genome-wide sequencing to characterize the cnidarian coral host and organelles from zooxanthellate endosymbionts (genus Cladocopium). We discover three distinct and sympatric genetic clusters of coral hosts, whose distributions appear associated with latitude and inshore-offshore reef position. Demographic modelling suggests that the divergence history of the three distinct host taxa ranges from 0.5 to 1.5 million years ago, preceding the GBR's formation, and has been characterized by low-to-moderate ongoing inter-taxon gene flow, consistent with occasional hybridization and introgression typifying coral evolution. Despite this differentiation in the cnidarian host, A. tenuis taxa share a common symbiont pool, dominated by the genus Cladocopium (Clade C). Cladocopium plastid diversity is not strongly associated with host identity but varies with reef location relative to shore: inshore colonies contain lower symbiont diversity on average but have greater differences between colonies as compared with symbiont communities from offshore colonies. Spatial genetic patterns of symbiont communities could reflect local selective pressures maintaining coral holobiont differentiation across an inshore-offshore environmental gradient. The strong influence of environment (but not host identity) on symbiont community composition supports the notion that symbiont community composition responds to habitat and may assist in the adaptation of corals to future environmental change.
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Affiliation(s)
- Ambrocio Melvin A. Matias
- Institute of BiologyUniversity of the Philippines DilimanQuezon CityPhilippines
- School of Biological SciencesThe University of QueenslandSt. LuciaQueenslandAustralia
| | - Iva Popovic
- School of Biological SciencesThe University of QueenslandSt. LuciaQueenslandAustralia
| | - Joshua A. Thia
- Bio21 Institute, School of BioSciencesThe University of MelbourneParkevilleVictoriaAustralia
| | - Ira R. Cooke
- College of Public Health, Medical and Veterinary SciencesJames Cook UniversityTownsvilleQueenslandAustralia
| | - Gergely Torda
- ARC Centre of Excellence for Coral Reef StudiesJames Cook UniversityTownsvilleQueenslandAustralia
| | - Vimoksalehi Lukoschek
- ARC Centre of Excellence for Coral Reef StudiesJames Cook UniversityTownsvilleQueenslandAustralia
- Gold Coast University HospitalQLD HealthSouthportQueenslandAustralia
| | - Line K. Bay
- Australian Institute of Marine ScienceTownsvilleQueenslandAustralia
| | - Sun W. Kim
- School of Biological SciencesThe University of QueenslandSt. LuciaQueenslandAustralia
| | - Cynthia Riginos
- School of Biological SciencesThe University of QueenslandSt. LuciaQueenslandAustralia
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19
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McDiarmid CS, Finch F, Peso M, van Rooij E, Hooper DM, Rowe M, Griffith SC. Experimentally testing mate preference in an avian system with unidirectional bill color introgression. Ecol Evol 2023; 13:e9812. [PMID: 36825134 PMCID: PMC9942114 DOI: 10.1002/ece3.9812] [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: 01/05/2023] [Accepted: 01/16/2023] [Indexed: 02/23/2023] Open
Abstract
Mating behavior can play a key role in speciation by inhibiting or facilitating gene flow between closely related taxa. Hybrid zones facilitate a direct examination of mating behavior and the traits involved in establishing species barriers. The long-tailed finch (Poephila acuticauda) has two hybridizing subspecies that differ in bill color (red and yellow), and the yellow bill phenotype appears to have introgressed ~350 km eastward following secondary contact. To examine the role of mate choice on bill color introgression, we performed behavioral assays using natural and manipulated bill colors. We found an assortative female mating preference for males of their own subspecies when bill color was not manipulated. However, we did not find this assortative preference in trials based on artificially manipulated bill color. This could suggest that assortative preference is not fixed entirely on bill color and instead may be based on a different trait (e.g., song) or a combination of traits, or alternatively may be due to lower statistical power alongside the bill manipulations being unconvincing to the female choosers. Intriguingly, we find a bias in the inheritance of bill color in captive bred F1 hybrid females. Previous modeling suggests that assortative mate preference and this kind of partial dominance in the underlying genes may together contribute to introgression, making the genetic architecture of bill color in this system a priority for future research.
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Affiliation(s)
- Callum S. McDiarmid
- School of Natural SciencesMacquarie UniversitySydneyNew South WalesAustralia
| | - Fiona Finch
- School of Natural SciencesMacquarie UniversitySydneyNew South WalesAustralia
| | - Marianne Peso
- School of Natural SciencesMacquarie UniversitySydneyNew South WalesAustralia
| | - Erica van Rooij
- School of Natural SciencesMacquarie UniversitySydneyNew South WalesAustralia
| | - Daniel M. Hooper
- Department of Biological SciencesColumbia UniversityNew YorkNew YorkUSA
- Institute for Comparative GenomicsAmerican Museum of Natural HistoryNew YorkNew YorkUSA
| | - Melissah Rowe
- Department of Animal EcologyNetherlands Institute of Ecology (NIOO‐KNAW)WageningenThe Netherlands
| | - Simon C. Griffith
- School of Natural SciencesMacquarie UniversitySydneyNew South WalesAustralia
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20
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Arce-Valdés LR, Sánchez-Guillén RA. The evolutionary outcomes of climate-change-induced hybridization in insect populations. CURRENT OPINION IN INSECT SCIENCE 2022; 54:100966. [PMID: 36089267 DOI: 10.1016/j.cois.2022.100966] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/23/2022] [Revised: 08/29/2022] [Accepted: 09/01/2022] [Indexed: 06/15/2023]
Abstract
Rapid range shifts are one of the most frequent responses to climate change in insect populations. Climate-induced range shifts can lead to the breakdown of isolation barriers, and thus, to an increase in hybridization and introgression. Long-term evolutionary consequences such as the formation of hybrid zones, introgression, speciation, and extinction have been predicted as a result of climate-induced hybridization. Our review shows that there has been an increase in the number of published cases of climate-induced hybridization in insects, and that the formation of hybrid zones and introgression seems to be, at the moment, the most frequent outcomes. Although introgression is considered positive, since it increases species' genetic diversity, in the long term, it could lead to negative outcomes such as species fusion or genetic swamping.
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Affiliation(s)
- Luis R Arce-Valdés
- Red de Biología Evolutiva, Instituto de Ecología, A.C. (INECOL), Carretera antigua a Coatepec 351, Col. El Haya, Xalapa, Veracruz C. P. 91073, Mexico
| | - Rosa A Sánchez-Guillén
- Red de Biología Evolutiva, Instituto de Ecología, A.C. (INECOL), Carretera antigua a Coatepec 351, Col. El Haya, Xalapa, Veracruz C. P. 91073, Mexico.
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21
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Alexander A, Robbins MB, Holmes J, Moyle RG, Peterson AT. Limited movement of an avian hybrid zone in relation to regional variation in magnitude of climate change. Mol Ecol 2022; 31:6634-6648. [PMID: 36210655 PMCID: PMC9729445 DOI: 10.1111/mec.16727] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2021] [Revised: 09/26/2022] [Accepted: 09/28/2022] [Indexed: 01/13/2023]
Abstract
Studies of natural hybrid zones can provide documentation of range shifts in response to climate change and identify loci important to reproductive isolation. Using a temporal (36-38 years) comparison of the black-capped (Poecile atricapillus) and Carolina (P. carolinensis) chickadee hybrid zone, we investigated movement of the western portion of the zone (western Missouri) and assessed whether loci and pathways underpinning reproductive isolation were similar to those in the eastern portion of the hybrid zone. Using 92 birds sampled along the hybrid zone transect in 2016 and 68 birds sampled between 1978 and 1980, we generated 11,669 SNPs via ddRADseq. These SNPs were used to assess movement of the hybrid zone through time and to evaluate variation in introgression among loci. We demonstrate that the interface has moved ~5 km to the northwest over the last 36-38 years, that is, at only one-fifth the rate at which the eastern portion (e.g., Pennsylvania, Ohio) of the hybrid zone has moved. Temperature trends over the last 38 years reveal that eastern areas have warmed 50% more than western areas in terms of annual mean temperature, possibly providing an explanation for the slower movement of the hybrid zone in Missouri. Our results suggest hybrid zone movement in broadly distributed species, such as chickadees, will vary between areas in response to local differences in the impacts of climate change.
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Affiliation(s)
- Alana Alexander
- Biodiversity InstituteUniversity of KansasLawrenceKansasUSA
- Department of AnatomyUniversity of OtagoDunedinNew Zealand
| | | | - Jesse Holmes
- Biodiversity InstituteUniversity of KansasLawrenceKansasUSA
- Department of Ecology and Evolutionary BiologyUniversity of KansasLawrenceKansasUSA
| | - Robert G. Moyle
- Biodiversity InstituteUniversity of KansasLawrenceKansasUSA
- Department of Ecology and Evolutionary BiologyUniversity of KansasLawrenceKansasUSA
| | - A. Townsend Peterson
- Biodiversity InstituteUniversity of KansasLawrenceKansasUSA
- Department of Ecology and Evolutionary BiologyUniversity of KansasLawrenceKansasUSA
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22
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Wang L, Liu S, Yang Y, Meng Z, Zhuang Z. Linked selection, differential introgression and recombination rate variation promote heterogeneous divergence in a pair of yellow croakers. Mol Ecol 2022; 31:5729-5744. [PMID: 36111361 PMCID: PMC9828471 DOI: 10.1111/mec.16693] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2021] [Accepted: 09/06/2022] [Indexed: 01/13/2023]
Abstract
Understanding the mechanisms underlying heterogeneous genomic divergence is of particular interest in evolutionary biology. Highly differentiated genomic regions, known as genomic islands, often evolve between diverging lineages. These genomic islands may be related to selection promoting adaptation or reproductive isolation. Based on whole genome assembly and genome-wide RAD sequencing in a pair of yellow croakers (genus: Larimichthys), we investigated the evolutionary processes shaping genomic landscapes of divergence. Demographic modelling indicated that the two species diverged following a secondary contact scenario, where differential introgression and linked selection were suggested to be involved in heterogeneous genomic divergence. We identified reduced recombination rate in genomic islands and a relatively good conservation of both genetic diversity and recombination landscapes between species, which highlight the roles of linked selection and recombination rate variation in promoting heterogeneous divergence in the common ancestral lineage of the two species. In addition, we found a positive correlation between differentiation (FST ) and absolute sequence divergence (Dxy ), and elevated Dxy in genomic islands, indicating that the genomic landscape of divergence was not shaped by linked selection alone. Restricted gene flow in highly differentiated regions has probably remodelled the landscape of heterogeneous genomic divergence. This study highlights that highly differentiated genomic regions can also arise from a combination of linked selection and differential gene flow in interaction with varying recombination rates.
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Affiliation(s)
- Le Wang
- State Key Laboratory of Biocontrol, Institute of Aquatic Economic Animals and the Guangdong Province Key Laboratory for Aquatic Economic Animals, School of Life SciencesSun Yat‐sen UniversityGuangzhouChina,Molecular Population Genetics Group, Temasek Life Sciences Laboratory, 1 Research LinkNational University of SingaporeSingapore CitySingapore
| | - Shufang Liu
- Yellow Sea Fisheries Research Institute, Chinese Academy of Fishery Sciences & Function Laboratory for Marine Biology and BiotechnologyQingdao National Laboratory for Marine Science and TechnologyQingdaoChina
| | - Yang Yang
- State Key Laboratory of Biocontrol, Institute of Aquatic Economic Animals and the Guangdong Province Key Laboratory for Aquatic Economic Animals, School of Life SciencesSun Yat‐sen UniversityGuangzhouChina
| | - Zining Meng
- State Key Laboratory of Biocontrol, Institute of Aquatic Economic Animals and the Guangdong Province Key Laboratory for Aquatic Economic Animals, School of Life SciencesSun Yat‐sen UniversityGuangzhouChina,Southern Laboratory of Ocean Science and EngineeringZhuhaiChina
| | - Zhimeng Zhuang
- Yellow Sea Fisheries Research Institute, Chinese Academy of Fishery Sciences & Function Laboratory for Marine Biology and BiotechnologyQingdao National Laboratory for Marine Science and TechnologyQingdaoChina
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23
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vonHoldt BM, Brzeski KE, Aardema ML, Schell CJ, Rutledge LY, Fain SR, Shutt AC, Linderholm A, Murphy WJ. Persistence and expansion of cryptic endangered red wolf genomic ancestry along the American Gulf coast. Mol Ecol 2022; 31:5440-5454. [PMID: 34585803 DOI: 10.1111/mec.16200] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2021] [Revised: 09/03/2021] [Accepted: 09/22/2021] [Indexed: 12/24/2022]
Abstract
Admixture and introgression play a critical role in adaptation and genetic rescue that has only recently gained a deeper appreciation. Here, we explored the geographical and genomic landscape of cryptic ancestry of the endangered red wolf that persists within the genome of a ubiquitous sister taxon, the coyote, all while the red wolf has been extinct in the wild since the early 1980s. We assessed admixture across 120,621 single nucleotiode polymorphism (SNP) loci genotyped in 293 canid genomes. We found support for increased red wolf ancestry along a west-to-east gradient across the southern United States associated with historical admixture in the past 100 years. Southwestern Louisiana and southeastern Texas, the geographical zone where the last red wolves were known prior to extinction in the wild, contained the highest and oldest levels of red wolf ancestry. Further, given the paucity of inferences based on chromosome types, we compared patterns of ancestry on the X chromosome and autosomes. We additionally aimed to explore the relationship between admixture timing and recombination rate variation to investigate gene flow events. We found that X-linked regions of low recombination rates were depleted of introgression, relative to the autosomes, consistent with the large X effect and enrichment with loci involved in maintaining reproductive isolation. Recombination rate was positively correlated with red wolf ancestry across coyote genomes, consistent with theoretical predictions. The geographical and genomic extent of cryptic red wolf ancestry can provide novel genomic resources for recovery plans targeting the conservation of the endangered red wolf.
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Affiliation(s)
- Bridgett M vonHoldt
- Ecology & Evolutionary Biology, Princeton University, Princeton, New Jersey, USA
| | - Kristin E Brzeski
- College of Forest Resources and Environment Science, Michigan Technological University, Houghton, Michigan, USA
| | - Matthew L Aardema
- Department of Biology, Montclair State University, Montclair, New Jersey, USA.,Sackler Institute for Comparative Genomics, American Museum of Natural History, New York, New York, USA
| | - Christopher J Schell
- Department of Environmental Science, Policy, and Management, University of California Berkeley, Berkeley, California, USA
| | - Linda Y Rutledge
- Biology Department, Trent University, Peterborough, Ontario, Canada
| | - Steven R Fain
- USFWS, Clark R. Bavin National Forensics Laboratory, Ashland, Oregon, USA
| | | | - Anna Linderholm
- Department of Anthropology, Texas A&M University, College Station, Texas, USA
| | - William J Murphy
- Veterinary Integrative Biosciences, Texas A&M University, College Station, Texas, USA
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24
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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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25
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Introgression at the emerging secondary contact zone of magpie Pica pica subspecies (Aves: Corvidae): integrating data on nuclear and mitochondrial markers, vocalizations, and field observations. ORG DIVERS EVOL 2022. [DOI: 10.1007/s13127-022-00568-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
Abstract
Zones of secondary contact provide a good opportunity to investigate the origin and dynamics of reproductive isolation between related populations. We analyzed genetic and phenotypic patterns and gene flow between two subspecies of the Eurasian magpie Pica pica s.l. which recently came into contact after presumably long periods of isolation. We describe the distribution of subspecies in a young contact zone at Argun’ river basin in southern Siberia where populations occur in parapatry and an older hybrid population in eastern Mongolia. Based on genome-wide SNP data, we analyzed patterns and strength of gene flow between the subspecies. Our results indicate occasional hybridization with backcrossing and asymmetric introgression along a wide range in Transbaikalia and locally in eastern Mongolia. Males of P. p. jankowskii apparently exhibit higher dispersal ability towards the west compared to P. p. leucoptera (towards the east). The former occasionally migrates to eastern Mongolia and Transbaikalia where introgression of nuclear, but not mitochondrial DNA was evident. Bioacoustic investigations showed differences between the subspecies in speed and structure of vocalization. We discovered intermediate calls of hybrid magpies and bilingual birds alternating calls that are typical for the two taxa. Furthermore, we found dramatically decreased reproductive success in hybridogeneous populations. By complementing our results with established phylogeographic patterns of P. pica s.l. based on a mitochondrial marker sequence, and considering indications of sterility of hybrids in the contact zone, we propose to elevate the two corresponding subspecies to species level: P. pica for the western form and P. serica for the eastern form.
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26
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Swaegers J, Sánchez-Guillén RA, Chauhan P, Wellenreuther M, Hansson B. Restricted X chromosome introgression and support for Haldane's rule in hybridizing damselflies. Proc Biol Sci 2022; 289:20220968. [PMID: 35855603 PMCID: PMC9297008 DOI: 10.1098/rspb.2022.0968] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
Contemporary hybrid zones act as natural laboratories for the investigation of species boundaries and may shed light on the little understood roles of sex chromosomes in species divergence. Sex chromosomes are considered to function as a hotspot of genetic divergence between species; indicated by less genomic introgression compared to autosomes during hybridization. Moreover, they are thought to contribute to Haldane's rule, which states that hybrids of the heterogametic sex are more likely to be inviable or sterile. To test these hypotheses, we used contemporary hybrid zones of Ischnura elegans, a damselfly species that has been expanding its range into the northern and western regions of Spain, leading to chronic hybridization with its sister species Ischnura graellsii. We analysed genome-wide SNPs in the Spanish I. elegans and I. graellsii hybrid zone and found (i) that the X chromosome shows less genomic introgression compared to autosomes, and (ii) that males are underrepresented among admixed individuals, as predicted by Haldane's rule. This is the first study in Odonata that suggests a role of the X chromosome in reproductive isolation. Moreover, our data add to the few studies on species with X0 sex determination system and contradict the hypothesis that the absence of a Y chromosome causes exceptions to Haldane's rule.
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Affiliation(s)
- Janne Swaegers
- Department of Biology, Lund University, Ecology Building, Lund 22362, Sweden,Evolutionary Stress Ecology and Ecotoxicology, KU Leuven, Leuven, Belgium
| | | | - Pallavi Chauhan
- Department of Biology, Lund University, Ecology Building, Lund 22362, Sweden
| | - Maren Wellenreuther
- The New Zealand Institute for Plant and Food Research Ltd, Nelson, New Zealand,School of Biological Sciences, University of Auckland, Auckland, New Zealand
| | - Bengt Hansson
- Department of Biology, Lund University, Ecology Building, Lund 22362, Sweden
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27
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Wu Z, Wang Z, Xie D, Zhang J, Cai P, Li X, Xu X, Li T, Zhao J. Extensive Sympatry and Frequent Hybridization of Ecologically Divergent Aquatic Plants on the Qinghai-Tibetan Plateau. FRONTIERS IN PLANT SCIENCE 2022; 13:851151. [PMID: 35646042 PMCID: PMC9135455 DOI: 10.3389/fpls.2022.851151] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 01/09/2022] [Accepted: 04/13/2022] [Indexed: 06/15/2023]
Abstract
Hybridization has fascinated biologists in recent centuries for its evolutionary importance, especially in plants. Hybrid zones are commonly located in regions across environmental gradients due to more opportunities to contact and ecological heterogeneity. For aquatic taxa, intrazonal character makes broad overlapping regions in intermediate environments between related species. However, we have limited information on the hybridization pattern of aquatic taxa in alpines, especially submerged macrophytes. In this study, we aimed to test the hypotheses that niche overlap and hybridization might be extensive in related aquatic plants across an altitudinal gradient. We evaluated the niche overlap in three related species pairs on the Qinghai-Tibetan Plateau and assessed the spatial pattern of hybrid populations. Obvious niche overlap and common hybridization were revealed in all three pairs of related aquatic plants. The plateau edge and river basins were broad areas for the sympatry of divergent taxa, where a large proportion of hybrid populations occurred. Hybrids are also discretely distributed in diverse habitats on the plateau. Differences in the extent of niche overlap, genetic incompatibility and phylogeographic history might lead to variation differences in hybridization patterns among the three species pairs. Our results suggested that plateau areas are a hotspot for ecologically divergent aquatic species to contact and mate and implied that hybridization may be important for the freshwater biodiversity of highlands.
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Affiliation(s)
- Zhigang Wu
- State Key Laboratory of Freshwater Ecology and Biotechnology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, China
| | - Zhong Wang
- Department of Ecology, College of Life Science, Wuhan University, Wuhan, China
| | - Dong Xie
- Co-Innovation Center for Sustainable Forestry in Southern China, College of Biology and the Environment, Nanjing Forestry University, Nanjing, China
- National Wetland Ecosystem Field Station of Taihu Lake, National Forestry Administration, Suzhou, China
| | - Juan Zhang
- Department of Ecology, College of Life Science, Wuhan University, Wuhan, China
| | - Pengsen Cai
- Department of Ecology, College of Life Science, Wuhan University, Wuhan, China
| | - Xing Li
- Department of Ecology, College of Life Science, Wuhan University, Wuhan, China
| | - Xinwei Xu
- Department of Ecology, College of Life Science, Wuhan University, Wuhan, China
| | - Tao Li
- State Key Laboratory of Freshwater Ecology and Biotechnology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, China
| | - Jindong Zhao
- State Key Laboratory of Freshwater Ecology and Biotechnology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, China
- State Key Laboratory of Protein and Plant Genetic Engineering, College of Life Sciences, Peking University, Beijing, China
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28
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Shepherd L, Simon C, Langton-Myers S, Morgan-Richards M. Insights into Aotearoa New Zealand’s biogeographic history provided by the study of natural hybrid zones. J R Soc N Z 2022. [DOI: 10.1080/03036758.2022.2061020] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Affiliation(s)
- Lara Shepherd
- Museum of New Zealand Te Papa Tongarewa, Wellington, New Zealand
| | - Chris Simon
- Department of Ecology and Evolutionary Biology, University of Connecticut, Storrs, CT, USA
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29
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Sequeira F, Arntzen JW, van Gulik D, Hajema S, Diaz RL, Wagt M, van Riemsdijk I. Genetic traces of hybrid zone movement across a fragmented habitat. J Evol Biol 2022; 35:400-412. [PMID: 35043504 DOI: 10.1111/jeb.13982] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2021] [Revised: 01/06/2022] [Accepted: 01/07/2022] [Indexed: 11/27/2022]
Abstract
Theoretical and empirical studies suggest that the structure and position of hybrid zones can change over time. Evidence for moving hybrid zones has been directly inferred by repeated sampling over time, or indirectly through the detection of genetic footprints left by the receding species and the resulting asymmetric patterns of introgression across markers. We here investigate a hybrid zone formed by two subspecies of the Iberian golden-striped salamander, Chioglossa lusitanica, using a panel of 35 nuclear loci (31 SNPs and 4 allozymes) and one mitochondrial locus in a transect in central Portugal. We found concordant and coincident clines for most of the nuclear loci (n=22, 63%), defining a narrow hybrid zone of ca. 6 km wide, with the centre positioned ca. 15 km south of the Mondego river. Asymmetric introgression was observed at another 14 loci. Their clines are displaced towards the north, with positions located either close to the Mondego river (n=6), or further northwards (n=8). We interpret these profiles as genetic traces of the southward displacement of C. lusitanica lusitanica by C. l. longipes over the wider Mondego river valley. We noted the absence of significant linkage disequilibrium and we inferred low levels of effective selection per locus against hybrids, suggesting that introgression in the area of species replacement occurred under a neutral diffusion process. A species distribution model suggests that the C. lusitanica hybrid zone coincides with a narrow corridor of fragmented habitat. From the position of the displaced clines, we infer that patches of locally suitable habitat trapped some genetic variants that became disassociated from the southward moving hybrid zone. This study highlights the influence of habitat availability on hybrid zone movement.
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Affiliation(s)
- Fernando Sequeira
- CIBIO, Centro de Investigação em Biodiversidade e Recursos Genéticos, InBIO Laboratório Associado, Universidade do Porto, Campus de Vairão, 4485-661, Vairão, Portugal.,BIOPOLIS Program in Genomics, Biodiversity and Land Planning, CIBIO, Campus de Vairão, 4485-661, Vairão, Portugal
| | - Jan W Arntzen
- Institute of Biology, Leiden University, Leiden, The Netherlands.,Naturalis Biodiversity Centre, P. O. Box 9517, 2300 RA, Leiden, The Netherlands
| | - Davy van Gulik
- Hogeschool Leiden, P. O. Box 382, 2300 AJ, Leiden, The Netherlands
| | - Steven Hajema
- Hogeschool Leiden, P. O. Box 382, 2300 AJ, Leiden, The Netherlands
| | - Ruben Lopez Diaz
- Hogeschool Leiden, P. O. Box 382, 2300 AJ, Leiden, The Netherlands
| | - Mattijn Wagt
- Hogeschool Leiden, P. O. Box 382, 2300 AJ, Leiden, The Netherlands
| | - Isolde van Riemsdijk
- Naturalis Biodiversity Centre, P. O. Box 9517, 2300 RA, Leiden, The Netherlands.,Hogeschool Leiden, P. O. Box 382, 2300 AJ, Leiden, The Netherlands
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30
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O'Donnell ST, Fitz-Gibbon ST, Sork VL. Ancient Introgression Between Distantly Related White Oaks (Quercus sect. Quercus) Shows Evidence of Climate-Associated Asymmetric Gene Exchange. J Hered 2021; 112:663-670. [PMID: 34508641 DOI: 10.1093/jhered/esab053] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2021] [Accepted: 09/10/2021] [Indexed: 12/14/2022] Open
Abstract
Ancient introgression can be an important source of genetic variation that shapes the evolution and diversification of many taxa. Here, we estimate the timing, direction, and extent of gene flow between two distantly related oak species in the same section (Quercus sect. Quercus). We estimated these demographic events using genotyping by sequencing data, which generated 25 702 single nucleotide polymorphisms for 24 individuals of California scrub oak (Quercus berberidifolia) and 23 individuals of Engelmann oak (Quercus engelmannii). We tested several scenarios involving gene flow between these species using the diffusion approximation-based population genetic inference framework and model-testing approach of the Python package DaDi. We found that the most likely demographic scenario includes a bottleneck in Q. engelmannii that coincides with asymmetric gene flow from Q. berberidifolia into Q. engelmannii. Given that the timing of this gene flow coincides with the advent of a Mediterranean-type climate in the California Floristic Province, we propose that changing precipitation patterns and seasonality may have favored the introgression of climate-associated genes from the endemic into the non-endemic California oak.
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Affiliation(s)
- Scott T O'Donnell
- Department of Ecology and Evolutionary Biology, University of California, Los Angeles, CA, USA
| | - Sorel T Fitz-Gibbon
- Department of Ecology and Evolutionary Biology, University of California, Los Angeles, CA, USA
| | - Victoria L Sork
- Institute of the Environment and Sustainability, University of California, Los Angeles, CA, USA
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31
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Guzmán NV, Kemppainen P, Monti D, Castillo ERD, Rodriguero MS, Sánchez-Restrepo AF, Cigliano MM, Confalonieri VA. Stable inversion clines in a grasshopper species group despite complex geographical history. Mol Ecol 2021; 31:1196-1215. [PMID: 34862997 DOI: 10.1111/mec.16305] [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: 05/21/2020] [Revised: 11/24/2021] [Accepted: 11/29/2021] [Indexed: 11/27/2022]
Abstract
Chromosomal inversions are known to play roles in adaptation and differentiation in many species. They involve clusters of correlated genes (i.e., loci in linkage disequilibrium, LD) possibly associated with environmental variables. The grasshopper "species complex" Trimerotropis pallidipennis comprises several genetic lineages distributed from North to South America in arid and semi-arid high-altitude environments. The southernmost lineage, Trimerotropis sp., segregates for four to seven putative inversions that display clinal variation, possibly through adaptation to temperate environments. We analysed chromosomal, mitochondrial and genome-wide single nucleotide polymorphism data in 19 Trimerotropis sp. populations mainly distributed along two altitudinal gradients (MS and Ju). Populations across Argentina comprise two main chromosomally and genetically differentiated lineages: one distributed across the southernmost border of the "Andes Centrales," adding evidence for a differentiation hotspot in this area; and the other widely distributed in Argentina. Within the latter, network analytical approaches to LD found three clusters of correlated loci (LD-clusters), with inversion karyotypes explaining >79% of the genetic variation. Outlier loci associated with environmental variables mapped to two of these LD-clusters. Furthermore, despite the complex geographical history indicated by population genetic analyses, the clines in inversion karyotypes have remained stable for more than 20 generations, implicating their role in adaptation and differentiation within this lineage. We hypothesize that these clines could be the consequence of a coupling between extrinsic postzygotic barriers and spatially varying selection along environmental gradients resulting in a hybrid zone. These results provide a framework for future investigations about candidate genes implicated in rapid adaptation to new environments.
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Affiliation(s)
- Noelia V Guzmán
- Departamento de Ecología, Genética y Evolución, FCEyN, Universidad de Buenos Aires (UBA), IEGEBA (Consejo Nacional de Investigaciones Científicas y Tecnológicas (CONICET)/UBA), Ciudad Universitaria, Buenos Aires, Argentina
| | - Petri Kemppainen
- Ecological Genetics Research Unit, Organismal and Evolutionary Biology Research Programme, Faculty of Biological and Environmental Sciences, University of Helsinki, Helsinki, Finland
| | - Daniela Monti
- Departamento de Ecología, Genética y Evolución, FCEyN, Universidad de Buenos Aires (UBA), IEGEBA (Consejo Nacional de Investigaciones Científicas y Tecnológicas (CONICET)/UBA), Ciudad Universitaria, Buenos Aires, Argentina
| | - Elio R D Castillo
- Laboratorio de Genética Evolutiva "Dr. Claudio J. Bidau", FCEQyN, Universidad Nacional de Misiones (UNaM), Instituto de Biología Subtropical (IBS) (CONICET/UNaM), LQH, Posadas, Misiones, Argentina
| | - Marcela S Rodriguero
- Departamento de Ecología, Genética y Evolución, FCEyN, Universidad de Buenos Aires (UBA), IEGEBA (Consejo Nacional de Investigaciones Científicas y Tecnológicas (CONICET)/UBA), Ciudad Universitaria, Buenos Aires, Argentina
| | - Andrés F Sánchez-Restrepo
- Departamento de Ecología, Genética y Evolución, FCEyN, Universidad de Buenos Aires (UBA), IEGEBA (Consejo Nacional de Investigaciones Científicas y Tecnológicas (CONICET)/UBA), Ciudad Universitaria, Buenos Aires, Argentina.,Fundación para el Estudio de Especies Invasivas (FuEDEI), Hurlingham, Buenos Aires, Argentina
| | - Maria Marta Cigliano
- Museo de La Plata, Centro de Estudios Parasitológicos y de Vectores (CEPAVE- CONICET/UNLP), Universidad Nacional de la Plata, Buenos Aires, Argentina
| | - Viviana A Confalonieri
- Departamento de Ecología, Genética y Evolución, FCEyN, Universidad de Buenos Aires (UBA), IEGEBA (Consejo Nacional de Investigaciones Científicas y Tecnológicas (CONICET)/UBA), Ciudad Universitaria, Buenos Aires, Argentina
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32
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Sánchez‐González LA, Castillo‐Chora VJ, Arbeláez‐Cortés E, Navarro‐Sigüenza AG. Diversification and secondary contact in the magpie‐jays (
Calocitta
) throughout the pacific lowlands of Mesoamerica. J ZOOL SYST EVOL RES 2021. [DOI: 10.1111/jzs.12571] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Luis A. Sánchez‐González
- Museo de Zoología “Alfonso L. Herrera” Facultad de Ciencias Universidad Nacional Autónoma de México Ciudad de México México
| | - Vicente J. Castillo‐Chora
- Museo de Zoología “Alfonso L. Herrera” Facultad de Ciencias Universidad Nacional Autónoma de México Ciudad de México México
- Posgrado en Ciencias Biológicas Universidad Nacional Autónoma de México Ciudad de México México
| | - Enrique Arbeláez‐Cortés
- Grupo de Estudios en Biodiversidad Escuela de Biología Universidad Industrial de Santander Bucaramanga Colombia
| | - Adolfo G. Navarro‐Sigüenza
- Museo de Zoología “Alfonso L. Herrera” Facultad de Ciencias Universidad Nacional Autónoma de México Ciudad de México México
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33
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Debnath T, Song M. Fast Optimal Circular Clustering and Applications on Round Genomes. IEEE/ACM TRANSACTIONS ON COMPUTATIONAL BIOLOGY AND BIOINFORMATICS 2021; 18:2061-2071. [PMID: 33945485 DOI: 10.1109/tcbb.2021.3077573] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
Round genomes are found in bacteria, plant chloroplasts, and mitochondria. Genetic or epigenetic marks can present biologically interesting clusters along a circular genome. The circular data clustering problem groups N points on a circle into K clusters to minimize the within-cluster sum of squared distances. Repeatedly applying the K-means algorithm takes quadratic time, impractical for large circular datasets. To overcome this issue, we developed a reproducible fast optimal circular clustering (FOCC) algorithm of worst-case O(KN log2 N) time. The core is a fast optimal framed clustering algorithm, which we designed by integrating two divide-and-conquer and one bracket dynamic programming strategies. The algorithm is optimal based on a property of monotonic increasing cluster borders over frames on linearized data. On clustering 50,000 circular data points, FOCC outruns brute-force or heuristic circular clustering by three orders of magnitude in time. We produced clusters of CpG sites and genes along three round genomes, exhibiting higher quality than heuristic clustering. More broadly, the presented subquadratic-time algorithms offer the fastest known solution to not only framed and circular clustering, but also angular, periodical, and looped clustering. We implemented these algorithms in the R package 'OptCirClust' (https://CRAN.R-project.org/package=OptCirClust).
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34
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Cruzan MB, Thompson PG, Diaz NA, Hendrickson EC, Gerloff KR, Kline KA, Machiorlete HM, Persinger JM. Weak coupling among barrier loci and waves of neutral and adaptive introgression across an expanding hybrid zone. Evolution 2021; 75:3098-3114. [PMID: 34668193 PMCID: PMC9298192 DOI: 10.1111/evo.14381] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2021] [Revised: 09/14/2021] [Accepted: 09/19/2021] [Indexed: 01/02/2023]
Abstract
Hybridization can serve as an evolutionary stimulus, but we have little understanding of introgression at early stages of hybrid zone formation. We analyze reproductive isolation and introgression between a range‐limited and a widespread species. Reproductive barriers are estimated based on differences in flowering time, ecogeographic distributions, and seed set from crosses. We find an asymmetrical mating barrier due to cytonuclear incompatibility that is consistent with observed clusters of coincident and concordant tension zone clines (barrier loci) for mtDNA haplotypes and nuclear SNPs. These groups of concordant clines are spread across the hybrid zone, resulting in weak coupling among barrier loci and extensive introgression. Neutral clines had nearly equal introgression into both species’ ranges, whereas putative cases of adaptive introgression had exceptionally wide clines with centers shifted toward one species. Analyses of cline shape indicate that secondary contact was initiated within the last 800 generations with the per‐generation dispersal between 200 and 400 m, and provide some of the first estimates of the strength of selection required to account for observed levels of adaptive introgression. The weak species boundary between these species appears to be in early stages of dissolution, and ultimately will precipitate genetic swamping of the range‐limited species.
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Affiliation(s)
- Mitchell B Cruzan
- Department of Biology, Portland State University, Portland, Oregon, 97201
| | - Pamela G Thompson
- Department of Biology, Portland State University, Portland, Oregon, 97201
| | - Nicolas A Diaz
- Department of Biology, Portland State University, Portland, Oregon, 97201
| | | | - Katie R Gerloff
- Department of Biology, Portland State University, Portland, Oregon, 97201
| | - Katie A Kline
- Department of Biology, Portland State University, Portland, Oregon, 97201
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35
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Powell DL, Moran B, Kim B, Banerjee SM, Aguillon SM, Fascinetto-Zago P, Langdon Q, Schumer M. Two new hybrid populations expand the swordtail hybridization model system. Evolution 2021; 75:2524-2539. [PMID: 34460102 PMCID: PMC8659863 DOI: 10.1111/evo.14337] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2021] [Revised: 06/11/2021] [Accepted: 06/22/2021] [Indexed: 12/25/2022]
Abstract
Natural hybridization events provide unique windows into the barriers that keep species apart as well as the consequences of their breakdown. Here, we characterize hybrid populations formed between the northern swordtail fish Xiphophorus cortezi and Xiphophorus birchmanni from collection sites on two rivers. We use simulations and new genetic reference panels to develop sensitive and accurate local ancestry calling in this novel system. Strikingly, we find that hybrid populations on both rivers consist of two genetically distinct subpopulations: a cluster of pure X. birchmanni individuals and one of phenotypically intermediate hybrids that derive ∼85-90% of their genome from X. cortezi. Simulations suggest that initial hybridization occurred ∼150 generations ago at both sites, with little evidence for contemporary gene flow between subpopulations. This population structure is consistent with strong assortative mating between individuals of similar ancestry. The patterns of population structure uncovered here mirror those seen in hybridization between X. birchmanni and its sister species, Xiphophorus malinche, indicating an important role for assortative mating in the evolution of hybrid populations. Future comparisons will provide a window into the shared mechanisms driving the outcomes of hybridization not only among independent hybridization events between the same species but also across distinct species pairs.
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Affiliation(s)
- Daniel L. Powell
- Department of Biology, Stanford University,Centro de Investigaciones Científicas de las Huastecas “Aguazarca”, A.C.,Correspondence to: and
| | - Ben Moran
- Department of Biology, Stanford University,Centro de Investigaciones Científicas de las Huastecas “Aguazarca”, A.C
| | | | - Shreya M. Banerjee
- Department of Biology, Stanford University,Centro de Investigaciones Científicas de las Huastecas “Aguazarca”, A.C
| | - Stepfanie M. Aguillon
- Department of Biology, Stanford University,Department of Ecology and Evolutionary Biology, Cornell University
| | - Paola Fascinetto-Zago
- Centro de Investigaciones Científicas de las Huastecas “Aguazarca”, A.C.,Department of Biology, Texas A&M University
| | - Quinn Langdon
- Department of Biology, Stanford University,Centro de Investigaciones Científicas de las Huastecas “Aguazarca”, A.C
| | - Molly Schumer
- Department of Biology, Stanford University,Centro de Investigaciones Científicas de las Huastecas “Aguazarca”, A.C.,Hanna H. Gray Fellow, Howard Hughes Medical Institutes,Correspondence to: and
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36
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Morales CC, Gómez JP, Parra JL. Patterns of morphological differentiation within Manacus manacus (Aves: Pipridae) in Colombia: revisiting hypotheses of isolation and secondary contact. Biol J Linn Soc Lond 2021. [DOI: 10.1093/biolinnean/blab106] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
Abstract
Determining the factors responsible for phenotypic variation within species is a fundamental task in evolutionary ecology. Isolation by distance, isolation by environment and clines along secondary contact zones between formerly isolated populations are common patterns of morphological variation. In this study, we evaluated whether patterns of morphological variation exhibit association with isolation by distance, isolation by environment or secondary contact in populations of Manacus manacus with contrasting plumage colour. We used field and museum measurements of five morphological characters from 311 individuals from 88 localities distributed across a highly heterogeneous environmental range within Colombia. Climatic variables explained a higher proportion of the variation than geographic distance among localities. We found differences in wing and culmen length between white and yellow phenotypes of M. manacus in Colombia. Overall morphology did not change in a clinal fashion in relation to the contact zone and the few traits that exhibit clinal variation suggest a distant locality for the contact zone, not in line with our expectations by secondary contact between differentiated populations, suggesting alternative mechanisms for differentiation between subspecies. Our results suggest that this species exhibits marked morphological variation associated with changes in temperature and precipitation. These associations are consistent throughout the geographic range analysed, leading us to postulate that dispersal and local adaptation jointly shape the distribution of phenotypic variation.
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Affiliation(s)
- Christian C Morales
- Grupo de Ecología y Evolución de Vertebrados, Instituto de Biología, Universidad de Antioquia, Medellín 050010, Colombia
| | - Juan P Gómez
- Departamento de Química y Biología, Universidad del Norte, Barranquilla 08001, Colombia
| | - Juan L Parra
- Grupo de Ecología y Evolución de Vertebrados, Instituto de Biología, Universidad de Antioquia, Medellín 050010, Colombia
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37
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Jahner JP, Parchman TL, Matocq MD. Multigenerational backcrossing and introgression between two woodrat species at an abrupt ecological transition. Mol Ecol 2021; 30:4245-4258. [PMID: 34219316 DOI: 10.1111/mec.16056] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2020] [Accepted: 06/28/2021] [Indexed: 12/27/2022]
Abstract
When organisms experience secondary contact after allopatric divergence, genomic regions can introgress differentially depending on their relationships with adaptation, reproductive isolation, recombination, and drift. Analyses of genome-wide patterns of divergence and introgression could provide insight into the outcomes of hybridization and the potential relationship between allopatric divergence and reproductive isolation. Here, we generate population genetic data (26,262 SNPs; 353 individuals) using a reduced-representation sequencing approach to quantify patterns of ancestry, differentiation, and introgression between a pair of ecologically distinct mammals-the desert woodrat (N. lepida) and Bryant's woodrat (N. bryanti)-that hybridize at a sharp ecotone in southern California. Individual ancestry estimates confirmed that hybrids were rare in this bimodal hybrid zone, and entirely consisted of a few F1 individuals and a broad range of multigenerational backcrosses. Genomic cline analyses indicated more than half of loci had elevated introgression from one genomic background into the other. However, introgression was not associated with relative or absolute measures of divergence, and loci with extreme values for both were not typically found near detoxification enzymes previously implicated in dietary specialization for woodrats. The decoupling of differentiation and introgression suggests that processes other than adaptation, such as drift, may underlie the extreme clines at this contact zone.
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Affiliation(s)
- Joshua P Jahner
- Department of Biology, University of Nevada, Reno, Nevada, USA.,Department of Botany, University of Wyoming, Laramie, Wyoming, USA
| | - Thomas L Parchman
- Department of Biology, University of Nevada, Reno, Nevada, USA.,Program in Ecology, Evolution, and Conservation Biology, University of Nevada, Reno, Nevada, USA
| | - Marjorie D Matocq
- Program in Ecology, Evolution, and Conservation Biology, University of Nevada, Reno, Nevada, USA.,Department of Natural Resources and Environmental Science, University of Nevada, Reno, Nevada, USA
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38
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Wen G, Fu J. Isolation and reconnection: Demographic history and multiple contact zones of the green odorous frog (Odorrana margaretae) around the Sichuan Basin. Mol Ecol 2021; 30:4103-4117. [PMID: 34145663 DOI: 10.1111/mec.16021] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2020] [Revised: 05/27/2021] [Accepted: 06/10/2021] [Indexed: 01/25/2023]
Abstract
The green odorous frog (Odorrana margaretae) displays a circular distribution around the Sichuan Basin of western China and possesses multiple replicate hybrid zones between lineages with high levels of divergence. To gain an understanding of the speciation process, we obtained 1540 SNPs from 29 populations and 227 individuals using ddRAD sequencing. Population structure analysis revealed three groups within the species: the West, North & South, and East groups. Demographic inference showed that they were initially isolated at ~2 million years ago, and subsequent post-glacial expansion produced the current circular distribution with four secondary contact zones. Hybridization in those zones involved lineages with various levels of divergence and produced greatly different patterns of introgression. Contact zones between the East and North & South groups (E-S and E-N) had contrast admixture levels but both showed a general lack of potential barrier loci. Meanwhile, the reconnection of the West and North & South groups produced two contact zones along the rim of the Basin. The S-W zone had extensive admixture while the N-W zone had limited admixture within a narrow geographic distance. Both showed substantial barrier effects, and a large number of potential barrier loci were shared. We also detected strong coupling among these loci. The N-W hybrid zone involved two highly-diverged lineages (FST = 0.704) and many loci have reached fixation around the hybrid zone. This study system offers a unique opportunity to understand the dynamics of introgression in contact zones and the architecture of reproductive isolation at different stages of speciation.
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Affiliation(s)
- Guannan Wen
- Chengdu Institute of Biology, Chinese Academy of Sciences, Chengdu, China.,University of Chinese Academy of Sciences, Beijing, China
| | - Jinzhong Fu
- Chengdu Institute of Biology, Chinese Academy of Sciences, Chengdu, China.,Department of Integrative Biology, University of Guelph, Guelph, ON, Canada
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39
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Koch EL, Morales HE, Larsson J, Westram AM, Faria R, Lemmon AR, Lemmon EM, Johannesson K, Butlin RK. Genetic variation for adaptive traits is associated with polymorphic inversions in Littorina saxatilis. Evol Lett 2021; 5:196-213. [PMID: 34136269 PMCID: PMC8190449 DOI: 10.1002/evl3.227] [Citation(s) in RCA: 31] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2020] [Revised: 02/06/2021] [Accepted: 03/29/2021] [Indexed: 01/11/2023] Open
Abstract
Chromosomal inversions have long been recognized for their role in local adaptation. By suppressing recombination in heterozygous individuals, they can maintain coadapted gene complexes and protect them from homogenizing effects of gene flow. However, to fully understand their importance for local adaptation we need to know their influence on phenotypes under divergent selection. For this, the marine snail Littorina saxatilis provides an ideal study system. Divergent ecotypes adapted to wave action and crab predation occur in close proximity on intertidal shores with gene flow between them. Here, we used F2 individuals obtained from crosses between the ecotypes to test for associations between genomic regions and traits distinguishing the Crab‐/Wave‐adapted ecotypes including size, shape, shell thickness, and behavior. We show that most of these traits are influenced by two previously detected inversion regions that are divergent between ecotypes. We thus gain a better understanding of one important underlying mechanism responsible for the rapid and repeated formation of ecotypes: divergent selection acting on inversions. We also found that some inversions contributed to more than one trait suggesting that they may contain several loci involved in adaptation, consistent with the hypothesis that suppression of recombination within inversions facilitates differentiation in the presence of gene flow.
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Affiliation(s)
- Eva L Koch
- Department of Animal and Plant Sciences University of Sheffield Sheffield United Kingdom
| | - Hernán E Morales
- Evolutionary Genetics Section Globe Institute University of Copenhagen Copenhagen Denmark.,Department of Marine Sciences University of Gothenburg Strömstad 45296 Sweden
| | - Jenny Larsson
- Department of Animal and Plant Sciences University of Sheffield Sheffield United Kingdom
| | - Anja M Westram
- Department of Animal and Plant Sciences University of Sheffield Sheffield United Kingdom.,IST Austria Klosterneuburg Austria
| | - Rui Faria
- Department of Animal and Plant Sciences University of Sheffield Sheffield United Kingdom.,CIBIO-InBIO, Centro de Investigação em Biodiversidade e Recursos Genéticos Universidade do Porto Vairão Portugal
| | - Alan R Lemmon
- Department of Scientific Computing Florida State University Tallahassee Florida FL 32306-4120
| | - E Moriarty Lemmon
- Department of Biological Science Florida State University Tallahassee Florida FL 32306-4295
| | - Kerstin Johannesson
- Department of Marine Sciences University of Gothenburg Strömstad 45296 Sweden
| | - Roger K Butlin
- Department of Animal and Plant Sciences University of Sheffield Sheffield United Kingdom.,Department of Marine Sciences University of Gothenburg Strömstad 45296 Sweden
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40
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Velo-Antón G, Lourenço A, Galán P, Nicieza A, Tarroso P. Landscape resistance constrains hybridization across contact zones in a reproductively and morphologically polymorphic salamander. Sci Rep 2021; 11:9259. [PMID: 33927228 PMCID: PMC8085075 DOI: 10.1038/s41598-021-88349-7] [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: 02/05/2021] [Accepted: 04/07/2021] [Indexed: 02/02/2023] Open
Abstract
Explicitly accounting for phenotypic differentiation together with environmental heterogeneity is crucial to understand the evolutionary dynamics in hybrid zones. Species showing intra-specific variation in phenotypic traits that meet across environmentally heterogeneous regions constitute excellent natural settings to study the role of phenotypic differentiation and environmental factors in shaping the spatial extent and patterns of admixture in hybrid zones. We studied three environmentally distinct contact zones where morphologically and reproductively divergent subspecies of Salamandra salamandra co-occur: the pueriparous S. s. bernardezi that is mostly parapatric to its three larviparous subspecies neighbours. We used a landscape genetics framework to: (i) characterise the spatial location and extent of each contact zone; (ii) assess patterns of introgression and hybridization between subspecies pairs; and (iii) examine the role of environmental heterogeneity in the evolutionary dynamics of hybrid zones. We found high levels of introgression between parity modes, and between distinct phenotypes, thus demonstrating the evolution to pueriparity alone or morphological differentiation do not lead to reproductive isolation between these highly divergent S. salamandra morphotypes. However, we detected substantial variation in patterns of hybridization across contact zones, being lower in the contact zone located on a topographically complex area. We highlight the importance of accounting for spatial environmental heterogeneity when studying evolutionary dynamics of hybrid zones.
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Affiliation(s)
- Guillermo Velo-Antón
- grid.5808.50000 0001 1503 7226CIBIO/InBIO, Centro de Investigação em Biodiversidade e Recursos Genéticos da Universidade do Porto, Instituto de Ciências Agrárias de Vairão. R. Padre Armando Quintas, 4485-661 Vairão, Portugal ,grid.6312.60000 0001 2097 6738Universidade de Vigo, Grupo de Ecoloxía Animal, Departamento de Ecoloxía e Bioloxía Animal, Torre Cacti (Lab 97), 36310 Vigo, Spain
| | - André Lourenço
- grid.5808.50000 0001 1503 7226CIBIO/InBIO, Centro de Investigação em Biodiversidade e Recursos Genéticos da Universidade do Porto, Instituto de Ciências Agrárias de Vairão. R. Padre Armando Quintas, 4485-661 Vairão, Portugal ,grid.5808.50000 0001 1503 7226Departamento de Biologia da Faculdade de Ciências, Universidade do Porto. Rua Campo Alegre, 4169-007 Porto, Portugal
| | - Pedro Galán
- grid.8073.c0000 0001 2176 8535Grupo de Investigación en Bioloxía Evolutiva (GIBE), Departamento de Bioloxía, Facultade de Ciencias, Universidade da Coruña, Campus da Zapateira, s/n, 15071 A Coruña, Spain
| | - Alfredo Nicieza
- grid.10863.3c0000 0001 2164 6351Departamento de Biologıa de Organismos y Sistemas, Universidad de Oviedo, Oviedo, Spain ,grid.10863.3c0000 0001 2164 6351Unidad Mixta de Investigacion en Biodiversidad (UMIB), CSIC-Universidad de Oviedo-Principado de Asturias, Mieres, Spain
| | - Pedro Tarroso
- grid.5808.50000 0001 1503 7226CIBIO/InBIO, Centro de Investigação em Biodiversidade e Recursos Genéticos da Universidade do Porto, Instituto de Ciências Agrárias de Vairão. R. Padre Armando Quintas, 4485-661 Vairão, Portugal
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41
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Pflugbeil G, Affenzeller M, Tribsch A, Comes HP. Primary hybrid zone formation in Tephroseris helenitis (Asteraceae), following postglacial range expansion along the central Northern Alps. Mol Ecol 2021; 30:1704-1720. [PMID: 33548078 PMCID: PMC8048512 DOI: 10.1111/mec.15832] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2020] [Revised: 01/26/2021] [Accepted: 01/27/2021] [Indexed: 11/26/2022]
Abstract
Distinguishing between secondary versus primary hybrid zone formation remains a challenging task as, for instance, the time window in which these historical (vicariant) versus contemporary (environmental-selective) processes are distinguishable may be relatively narrow. Here, we examine the origin and structure of a transition zone between two subspecies of Tephroseris helenitis along the central Northern Alps, using molecular (AFLP) and morphological (achene type) data in combination with ecological niche models (ENMs) to hindcast ranges at the Last Glacial Maximum (LGM) and mid-Holocene. Samples were collected over a c. 350 km long transect, largely covered by ice during the LGM. Genetically nonadmixed individuals of subspp. helenitis versus salisburgensis dominated the westernmost versus eastern transect areas, with admixed individuals occurring in between. Clines for achene morphology and outlier loci potentially under climate-driven selection were steep, largely noncoincidental, and displaced to the east of the cline centre for neutral AFLPs. During the LGM, ssp. helenitis should have been able to persist in a refugium southwest of the transect, while suitable habitat for ssp. salisburgensis was apparently absent at this time. Together with patterns of genetic and clinal variation, our ENM data are suggestive of a primary hybrid zone that originated after the species' postglacial, eastward expansion. The observed clinal changes may thus reflect random/nonadaptive processes during expansion and selection on particular loci, and possibly achene type, in response to a long-term, west-to-east climate gradient in the direction of more stressful (e.g., wetter/cooler) conditions. Overall, this study adds to the vast hybrid zone literature a rare example of a hybrid zone caused by primary differentiation within a plant species, underlaid by historical range expansion.
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Affiliation(s)
- Georg Pflugbeil
- Department of Biosciences, University of Salzburg, Salzburg, Austria
| | | | - Andreas Tribsch
- Department of Biosciences, University of Salzburg, Salzburg, Austria
| | - Hans Peter Comes
- Department of Biosciences, University of Salzburg, Salzburg, Austria
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42
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Shastry V, Adams PE, Lindtke D, Mandeville EG, Parchman TL, Gompert Z, Buerkle CA. Model-based genotype and ancestry estimation for potential hybrids with mixed-ploidy. Mol Ecol Resour 2021; 21:1434-1451. [PMID: 33482035 DOI: 10.1111/1755-0998.13330] [Citation(s) in RCA: 22] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2020] [Revised: 12/11/2020] [Accepted: 01/11/2021] [Indexed: 11/29/2022]
Abstract
Non-random mating among individuals can lead to spatial clustering of genetically similar individuals and population stratification. This deviation from panmixia is commonly observed in natural populations. Consequently, individuals can have parentage in single populations or involving hybridization between differentiated populations. Accounting for this mixture and structure is important when mapping the genetics of traits and learning about the formative evolutionary processes that shape genetic variation among individuals and populations. Stratified genetic relatedness among individuals is commonly quantified using estimates of ancestry that are derived from a statistical model. Development of these models for polyploid and mixed-ploidy individuals and populations has lagged behind those for diploids. Here, we extend and test a hierarchical Bayesian model, called entropy, which can use low-depth sequence data to estimate genotype and ancestry parameters in autopolyploid and mixed-ploidy individuals (including sex chromosomes and autosomes within individuals). Our analysis of simulated data illustrated the trade-off between sequencing depth and genome coverage and found lower error associated with low-depth sequencing across a larger fraction of the genome than with high-depth sequencing across a smaller fraction of the genome. The model has high accuracy and sensitivity as verified with simulated data and through analysis of admixture among populations of diploid and tetraploid Arabidopsis arenosa.
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Affiliation(s)
| | - Paula E Adams
- Department of Biological Sciences, University of Alabama, Tuscaloosa, AL, USA
| | - Dorothea Lindtke
- Institute of Plant Sciences, University of Bern, Bern, Switzerland
| | | | | | | | - C Alex Buerkle
- Department of Botany, University of Wyoming, Laramie, WY, USA
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43
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Melander SL, Mueller RL. Comprehensive Analysis of Salamander Hybridization Suggests a Consistent Relationship between Genetic Distance and Reproductive Isolation across Tetrapods. COPEIA 2020. [DOI: 10.1643/ch-19-319] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Affiliation(s)
- Scott Lucas Melander
- Department of Biology, Colorado State University, 251 W Pitkin Street, Fort Collins, Colorado 80523; (SLM) ; and (RLM) . Send reprint requests to SLM
| | - Rachel Lockridge Mueller
- Department of Biology, Colorado State University, 251 W Pitkin Street, Fort Collins, Colorado 80523; (SLM) ; and (RLM) . Send reprint requests to SLM
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44
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Popovic I, Bierne N, Gaiti F, Tanurdžić M, Riginos C. Pre-introduction introgression contributes to parallel differentiation and contrasting hybridization outcomes between invasive and native marine mussels. J Evol Biol 2020; 34:175-192. [PMID: 33251632 DOI: 10.1111/jeb.13746] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2019] [Revised: 11/01/2020] [Accepted: 11/11/2020] [Indexed: 12/28/2022]
Abstract
Non-native species experience novel selection pressures in introduced environments and may interbreed with native lineages. Species introductions therefore provide opportunities to investigate repeated patterns of adaptation and introgression across replicated contact zones. Here, we investigate genetic parallelism between multiple introduced populations of the invasive marine mussel, Mytilus galloprovincialis, in the absence (South Africa and California) and presence of hybridization with a native congener (Mytilus planulatus in Batemans Bay and Sydney Harbour, Australia). Repeatability in post-introduction differentiation from native-range populations varied between genetically distinct Atlantic and Mediterranean lineages, with Atlantic-derived introductions displaying high differentiation (maxFST > 0.4) and parallelism at outlier loci. Identification of long noncoding RNA transcripts (lncRNA) additionally allowed us to clarify that parallel responses are largely limited to protein-coding loci, with lncRNAs likely evolving under evolutionary constraints. Comparisons of independent hybrid zones revealed differential introgression most strongly in Batemans Bay, with an excess of M. galloprovincialis ancestry and resistance to introgression at loci differentiating parental lineages (M. planulatus and Atlantic M. galloprovincialis). Additionally, contigs putatively introgressed with divergent alleles from a closely related species, Mytilus edulis, showed stronger introgression asymmetries compared with genome-wide trends and also diverged in parallel in both Atlantic-derived introductions. These results suggest that divergent demographic histories experienced by introduced lineages, including pre-introduction introgression, influence contemporary admixture dynamics. Our findings build on previous investigations reporting contributions of historical introgression to intrinsic reproductive architectures shared between marine lineages and illustrate that interspecific introgression history can shape differentiation between colonizing populations and their hybridization with native congeners.
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Affiliation(s)
- Iva Popovic
- School of Biological Sciences, University of Queensland, St Lucia, Qld, Australia
| | - Nicolas Bierne
- Institut des Sciences de l'Evolution UMR 5554, Université de Montpellier, CNRS-IRD-EPHE-UM, Montpellier, France
| | - Federico Gaiti
- Weill Cornell Medicine, New York, NY, USA.,New York Genome Center, New York, NY, USA
| | - Miloš Tanurdžić
- School of Biological Sciences, University of Queensland, St Lucia, Qld, Australia
| | - Cynthia Riginos
- School of Biological Sciences, University of Queensland, St Lucia, Qld, Australia
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45
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Ostevik KL, Rifkin JL, Xia H, Rausher MD. Morning glory species co-occurrence is associated with asymmetrically decreased and cascading reproductive isolation. Evol Lett 2020; 5:75-85. [PMID: 33552537 PMCID: PMC7857285 DOI: 10.1002/evl3.205] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2020] [Revised: 10/04/2020] [Accepted: 10/19/2020] [Indexed: 01/25/2023] Open
Abstract
Hybridization between species can affect the strength of the reproductive barriers that separate those species. Two extensions of this effect are (1) the expectation that asymmetric hybridization or gene flow will have asymmetric effects on reproductive barrier strength and (2) the expectation that local hybridization will affect only local reproductive barrier strength and could therefore alter within‐species compatibility. We tested these hypotheses in a pair of morning glory species that exhibit asymmetric gene flow from highly selfing Ipomoea lacunosa into mixed‐mating Ipomoea cordatotriloba in regions where they co‐occur. Because of the direction of this gene flow, we predicted that reproductive barrier strength would be more strongly affected in I. cordatotriloba than I. lacunosa. We also predicted that changes to reproductive barriers in sympatric I. cordatotriloba populations would affect compatibility with allopatric populations of that species. We tested these predictions by measuring the strength of a reproductive barrier to seed set across the species’ ranges. Consistent with our first prediction, we found that sympatric and allopatric I. lacunosa produce the same number of seeds in crosses with I. cordatotriloba, whereas crosses between sympatric I. cordatotriloba and I. lacunosa are more successful than crosses between allopatric I. cordatotriloba and I. lacunosa. This difference in compatibility appears to reflect an asymmetric decrease in the strength of the barrier to seed set in sympatric I. cordatotriloba, which could be caused by I. lacunosa alleles that have introgressed into I. cordatotriloba. We further demonstrated that changes to sympatric I. cordatotriloba have decreased its ability to produce seeds with allopatric populations of the same species, in line with our second prediction. Thus, in a manner analogous to cascade reinforcement, we suggest that introgression associated with hybridization not only influences between‐species isolation but can also contribute to isolation within a species.
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Affiliation(s)
- Kate L Ostevik
- Department of Biology Duke University Durham North Carolina 27708
| | - Joanna L Rifkin
- Department of Ecology and Evolutionary Biology University of Toronto Toronto ON M5S 3B2 Canada
| | - Hanhan Xia
- College of Horticulture and Landscape Architecture Zhongkai University of Agriculture and Engineering Guangzhou 510225 China
| | - Mark D Rausher
- Department of Biology Duke University Durham North Carolina 27708
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46
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Kirschel ANG, Nwankwo EC, Pierce DK, Lukhele SM, Moysi M, Ogolowa BO, Hayes SC, Monadjem A, Brelsford A. CYP2J19 mediates carotenoid colour introgression across a natural avian hybrid zone. Mol Ecol 2020; 29:4970-4984. [PMID: 33058329 DOI: 10.1111/mec.15691] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2020] [Revised: 10/02/2020] [Accepted: 10/05/2020] [Indexed: 02/06/2023]
Abstract
It has long been of interest to identify the phenotypic traits that mediate reproductive isolation between related species, and more recently, the genes that underpin them. Much work has focused on identifying genes associated with animal colour, with the candidate gene CYP2J19 identified in laboratory studies as the ketolase converting yellow dietary carotenoids to red ketocarotenoids in birds with red pigments. However, evidence that CYP2J19 explains variation between red and yellow feather coloration in wild populations of birds is lacking. Hybrid zones provide the opportunity to identify genes associated with specific traits. Here we investigate genomic regions associated with colour in red-fronted and yellow-fronted tinkerbirds across a hybrid zone in southern Africa. We sampled 85 individuals, measuring spectral reflectance of forecrown feathers and scoring colours from photographs, while testing for carotenoid presence with Raman spectroscopy. We performed a genome-wide association study to identify associations with carotenoid-based coloration, using double-digest RAD sequencing aligned to a short-read whole genome of a Pogoniulus tinkerbird. Admixture mapping using 104,933 single nucleotide polymorphisms (SNPs) identified a region of chromosome 8 that includes CYP2J19 as the only locus with more than two SNPs significantly associated with both crown hue and crown score, while Raman spectra provided evidence of ketocarotenoids in red feathers. Asymmetric backcrossing in the hybrid zone suggests that yellow-fronted females mate more often with red-fronted males than vice versa. Female red-fronted tinkerbirds mating assortatively with red-crowned males is consistent with the hypothesis that converted carotenoids are an honest signal of quality.
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Affiliation(s)
| | - Emmanuel C Nwankwo
- Department of Biological Sciences, University of Cyprus, Nicosia, Cyprus
| | - Daniel K Pierce
- Department of Evolution, Ecology, and Organismal Biology, University of California Riverside, Riverside, CA, USA
| | - Sifiso M Lukhele
- Department of Biological Sciences, University of Cyprus, Nicosia, Cyprus
| | - Michaella Moysi
- Department of Biological Sciences, University of Cyprus, Nicosia, Cyprus
| | - Bridget O Ogolowa
- Department of Biological Sciences, University of Cyprus, Nicosia, Cyprus
| | - Sophia C Hayes
- Department of Chemistry, University of Cyprus, Nicosia, Cyprus
| | - Ara Monadjem
- Department of Biological Sciences, University of Eswatini, Kwaluseni, Eswatini.,Department of Zoology & Entomology, Mammal Research Institute, University of Pretoria, Hatfield, South Africa
| | - Alan Brelsford
- Department of Evolution, Ecology, and Organismal Biology, University of California Riverside, Riverside, CA, USA
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Simon A, Fraïsse C, El Ayari T, Liautard-Haag C, Strelkov P, Welch JJ, Bierne N. How do species barriers decay? Concordance and local introgression in mosaic hybrid zones of mussels. J Evol Biol 2020; 34:208-223. [PMID: 33045123 DOI: 10.1111/jeb.13709] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2019] [Revised: 08/20/2020] [Accepted: 09/16/2020] [Indexed: 12/19/2022]
Abstract
The Mytilus complex of marine mussel species forms a mosaic of hybrid zones, found across temperate regions of the globe. This allows us to study 'replicated' instances of secondary contact between closely related species. Previous work on this complex has shown that local introgression is both widespread and highly heterogeneous, and has identified SNPs that are outliers of differentiation between lineages. Here, we developed an ancestry-informative panel of such SNPs. We then compared their frequencies in newly sampled populations, including samples from within the hybrid zones, and parental populations at different distances from the contact. Results show that close to the hybrid zones, some outlier loci are near to fixation for the heterospecific allele, suggesting enhanced local introgression, or the local sweep of a shared ancestral allele. Conversely, genomic cline analyses, treating local parental populations as the reference, reveal a globally high concordance among loci, albeit with a few signals of asymmetric introgression. Enhanced local introgression at specific loci is consistent with the early transfer of adaptive variants after contact, possibly including asymmetric bi-stable variants (Dobzhansky-Muller incompatibilities), or haplotypes loaded with fewer deleterious mutations. Having escaped one barrier, however, these variants can be trapped or delayed at the next barrier, confining the introgression locally. These results shed light on the decay of species barriers during phases of contact.
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Affiliation(s)
- Alexis Simon
- ISEM, Univ Montpellier, CNRS, EPHE, IRD, Montpellier, France
| | - Christelle Fraïsse
- ISEM, Univ Montpellier, CNRS, EPHE, IRD, Montpellier, France.,Institute of Science and Technology Austria, Klosterneuburg, Austria, Austria
| | - Tahani El Ayari
- ISEM, Univ Montpellier, CNRS, EPHE, IRD, Montpellier, France
| | | | - Petr Strelkov
- St. Petersburg State University, St. Petersburg, Russia.,Laboratory of Monitoring and Conservation of Natural Arctic Ecosystems, Murmansk Arctic State University, Murmansk, Russia
| | - John J Welch
- Department of Genetics, University of Cambridge, Cambridge, UK
| | - Nicolas Bierne
- ISEM, Univ Montpellier, CNRS, EPHE, IRD, Montpellier, France
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48
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Akopyan M, Gompert Z, Klonoski K, Vega A, Kaiser K, Mackelprang R, Rosenblum EB, Robertson JM. Genetic and phenotypic evidence of a contact zone between divergent colour morphs of the iconic red-eyed treefrog. Mol Ecol 2020; 29:4442-4456. [PMID: 32945036 DOI: 10.1111/mec.15639] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2020] [Revised: 07/21/2020] [Accepted: 09/03/2020] [Indexed: 12/28/2022]
Abstract
Hybrid zones act as natural laboratories where divergent genomes interact, providing powerful systems for examining the evolutionary processes underlying biological diversity. In this study, we characterized patterns of genomic and phenotypic variation resulting from hybridization between divergent intraspecific lineages of the Neotropical red-eyed treefrog (Agalychnis callidryas). We found genetic evidence of a newly discovered contact zone and phenotypic novelty in leg colour-a trait suspected to play a role in mediating assortative mating in this species. Analysis of hybrid ancestry revealed an abundance of later-generation Fn individuals, suggesting persistence of hybrids in the contact zone. Hybrids are predominantly of southern ancestry but are phenotypically more similar to northern populations. Genome-wide association mapping revealed QTL with measurable effects on leg-colour variation, but further work is required to dissect the architecture of this trait and establish causal links. Further, genomic cline analyses indicated substantial variation in patterns of introgression across the genome. Directional introgression of loci associated with different aspects of leg colour are inherited from each parental lineage, creating a distinct hybrid colour pattern. We show that hybridization can generate new phenotypes, revealing the evolutionary processes that potentially underlie patterns of phenotypic diversity in this iconic polytypic frog. Our study is consistent with a role of hybridization and sexual selection in lineage diversification, evolutionary processes that have been implicated in accelerating divergence in the most phenotypically diverse species.
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Affiliation(s)
- Maria Akopyan
- Department of Ecology and Evolutionary Biology, Cornell University, Ithaca, NY, USA.,Department of Biology, California State University, Northridge, CA, USA
| | | | - Karina Klonoski
- Department of Environmental Science, Policy, and Management, University of California, Berkeley, CA, USA
| | | | - Kristine Kaiser
- Department of Biology, California State University, Northridge, CA, USA
| | | | - Erica Bree Rosenblum
- Department of Environmental Science, Policy, and Management, University of California, Berkeley, CA, USA
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49
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McLaughlin JF, Faircloth BC, Glenn TC, Winker K. Divergence, gene flow, and speciation in eight lineages of trans-Beringian birds. Mol Ecol 2020; 29:3526-3542. [PMID: 32745340 DOI: 10.1111/mec.15574] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2019] [Revised: 07/22/2020] [Accepted: 07/27/2020] [Indexed: 12/13/2022]
Abstract
Determining how genetic diversity is structured between populations that span the divergence continuum from populations to biological species is key to understanding the generation and maintenance of biodiversity. We investigated genetic divergence and gene flow in eight lineages of birds with a trans-Beringian distribution, where Asian and North American populations have likely been split and reunited through multiple Pleistocene glacial cycles. Our study transects the speciation process, including eight pairwise comparisons in three orders (ducks, shorebirds and passerines) at population, subspecies and species levels. Using ultraconserved elements (UCEs), we found that these lineages represent conditions from slightly differentiated populations to full biological species. Although allopatric speciation is considered the predominant mode of divergence in birds, all of our best divergence models included gene flow, supporting speciation with gene flow as the predominant mode in Beringia. In our eight lineages, three were best described by a split-migration model (divergence with gene flow), three best fit a secondary contact scenario (isolation followed by gene flow), and two showed support for both models. The lineages were not evenly distributed across a divergence space defined by gene flow (M) and differentiation (FST ), instead forming two discontinuous groups: one with relatively shallow divergence, no fixed single nucleotide polymorphisms (SNPs), and high rates of gene flow between populations; and the second with relatively deeply divergent lineages, multiple fixed SNPs, and low gene flow. Our results highlight the important role that gene flow plays in avian divergence in Beringia.
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Affiliation(s)
- Jessica F McLaughlin
- University of Alaska Museum, Fairbanks, AK, USA.,Sam Noble Oklahoma Museum of Natural History, Norman, OK, USA
| | - Brant C Faircloth
- Department of Biological Sciences and Museum of Natural Science, Louisiana State University, Baton Rouge, LA, USA
| | - Travis C Glenn
- Department of Environmental Health Science and Institute of Bioinformatics, University of Georgia, Athens, GA, USA
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50
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Satokangas I, Martin SH, Helanterä H, Saramäki J, Kulmuni J. Multi-locus interactions and the build-up of reproductive isolation. Philos Trans R Soc Lond B Biol Sci 2020; 375:20190543. [PMID: 32654649 PMCID: PMC7423273 DOI: 10.1098/rstb.2019.0543] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/26/2020] [Indexed: 12/15/2022] Open
Abstract
All genes interact with other genes, and their additive effects and epistatic interactions affect an organism's phenotype and fitness. Recent theoretical and empirical work has advanced our understanding of the role of multi-locus interactions in speciation. However, relating different models to one another and to empirical observations is challenging. This review focuses on multi-locus interactions that lead to reproductive isolation (RI) through reduced hybrid fitness. We first review theoretical approaches and show how recent work incorporating a mechanistic understanding of multi-locus interactions recapitulates earlier models, but also makes novel predictions concerning the build-up of RI. These include high variance in the build-up rate of RI among taxa, the emergence of strong incompatibilities producing localized barriers to introgression, and an effect of population size on the build-up of RI. We then review recent experimental approaches to detect multi-locus interactions underlying RI using genomic data. We argue that future studies would benefit from overlapping methods like ancestry disequilibrium scans, genome scans of differentiation and analyses of hybrid gene expression. Finally, we highlight a need for further overlap between theoretical and empirical work, and approaches that predict what kind of patterns multi-locus interactions resulting in incompatibilities will leave in genome-wide polymorphism data. This article is part of the theme issue 'Towards the completion of speciation: the evolution of reproductive isolation beyond the first barriers'.
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Affiliation(s)
- I. Satokangas
- Organismal & Evolutionary Biology Research Programme, University of Helsinki, Viikinkaari 1, PO Box 65, 00014 Helsinki, Finland
| | - S. H. Martin
- Institute of Evolutionary Biology, University of Edinburgh, Ashworth Laboratories, Edinburgh EH9 3FL, UK
| | - H. Helanterä
- Ecology and Genetics research unit, University of Oulu, PO Box 3000, 90014 Oulu, Finland
| | - J. Saramäki
- Department of Computer Science, Aalto University, PO Box 11000, 00076 Aalto, Espoo, Finland
| | - J. Kulmuni
- Organismal & Evolutionary Biology Research Programme, University of Helsinki, Viikinkaari 1, PO Box 65, 00014 Helsinki, Finland
- Tvärminne Zoological Station, University of Helsinki, J. A. Palménin tie 260, 10900 Hanko, Finland
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