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Wanders K, Chen G, Feng S, Székely T, Urrutia AO. Role-reversed polyandry is associated with faster fast-Z in shorebirds. Proc Biol Sci 2024; 291:20240397. [PMID: 38864333 DOI: 10.1098/rspb.2024.0397] [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: 09/30/2023] [Accepted: 05/14/2024] [Indexed: 06/13/2024] Open
Abstract
In birds, males are homogametic and carry two copies of the Z chromosome ('ZZ'), while females are heterogametic and exhibit a 'ZW' genotype. The Z chromosome evolves at a faster rate than similarly sized autosomes, a phenomenon termed 'fast-Z evolution'. This is thought to be caused by two independent processes-greater Z chromosome genetic drift owing to a reduced effective population size, and stronger Z chromosome positive selection owing to the exposure of partially recessive alleles to selection. Here, we investigate the relative contributions of these processes by considering the effect of role-reversed polyandry on fast-Z in shorebirds, a paraphyletic group of wading birds that exhibit unusually diverse mating systems. We find stronger fast-Z effects under role-reversed polyandry, which is consistent with particularly strong selection on polyandrous females driving the fixation of recessive beneficial alleles. This result contrasts with previous research in birds, which has tended to implicate a primary role of genetic drift in driving fast-Z variation. We suggest that this discrepancy can be interpreted in two ways-stronger sexual selection acting on polyandrous females overwhelms an otherwise central role of genetic drift, and/or sexual antagonism is also contributing significantly to fast-Z and is exacerbated in sexually dimorphic species.
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Affiliation(s)
- Kees Wanders
- Department of Life Sciences, Milner Centre for Evolution, University of Bath , Bath, UK
- Department of Evolutionary Zoology and Human Biology, HUN-REN-DE Reproductive strategies Research Group, University of Debrecen , Debrecen, Hungary
- Natural History Museum of Denmark, University of Copenhagen , Copenhagen, Denmark
| | - Guangji Chen
- Center for Evolutionary & Organismal Biology, Liangzhu Laboratory, Department of General Surgery, Sir Run Run Shaw Hospital, Zhejiang University School of Medicine , Hangzhou, People's Republic of China
- BGI Research , Wuhan, People's Republic of China
- College of Life Sciences, University of Chinese Academy of Sciences , Beijing, People's Republic of China
| | - Shaohong Feng
- Center for Evolutionary & Organismal Biology, Liangzhu Laboratory, Department of General Surgery, Sir Run Run Shaw Hospital, Zhejiang University School of Medicine , Hangzhou, People's Republic of China
| | - Tamás Székely
- Department of Life Sciences, Milner Centre for Evolution, University of Bath , Bath, UK
- Department of Evolutionary Zoology and Human Biology, HUN-REN-DE Reproductive strategies Research Group, University of Debrecen , Debrecen, Hungary
- Debrecen Biodiversity Centre, University of Debrecen , Debrecen, Hungary
| | - Arraxi O Urrutia
- Department of Life Sciences, Milner Centre for Evolution, University of Bath , Bath, UK
- Instituto de Ecologia, UNAM , Mexico City, Mexico
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Setti PG, Deon GA, Zeni Dos Santos R, Goes CAG, Garnero ADV, Gunski RJ, de Oliveira EHC, Porto-Foresti F, de Freitas TRO, Silva FAO, Liehr T, Utsunomia R, Kretschmer R, de Bello Cioffi M. Evolution of bird sex chromosomes: a cytogenomic approach in Palaeognathae species. BMC Ecol Evol 2024; 24:51. [PMID: 38654159 PMCID: PMC11036779 DOI: 10.1186/s12862-024-02230-5] [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: 12/07/2023] [Accepted: 03/26/2024] [Indexed: 04/25/2024] Open
Abstract
BACKGROUND Different patterns of sex chromosome differentiation are seen in Palaeognathae birds, a lineage that includes the ratites (Struthioniformes, Rheiformes, Apterygiformes, Casuariiformes, and the sister group Tinamiformes). While some Tinamiform species have well-differentiated W chromosomes, both Z and W of all the flightless ratites are still morphologically undifferentiated. Here, we conducted a comprehensive analysis of the ZW differentiation in birds using a combination of cytogenetic, genomic, and bioinformatic approaches. The whole set of satDNAs from the emu (Dromaius novaehollandiae) was described and characterized. Furthermore, we examined the in situ locations of these satDNAs alongside several microsatellite repeats and carried out Comparative Genomic Hybridizations in two related species: the greater rhea (Rhea americana) and the tataupa tinamou (Crypturellus tataupa). RESULTS From the 24 satDNA families identified (which represent the greatest diversity of satDNAs ever uncovered in any bird species), only three of them were found to accumulate on the emu's sex chromosomes, with no discernible accumulation observed on the W chromosome. The W chromosomes of both the greater rhea and the emu did not exhibit a significant buildup of either C-positive heterochromatin or repetitive DNAs, indicating their large undifferentiation both at morphological and molecular levels. In contrast, the tataupa tinamou has a highly differentiated W chromosome that accumulates several DNA repeats. CONCLUSION The findings provide new information on the architecture of the avian genome and an inside look at the starting points of sex chromosome differentiation in birds.
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Affiliation(s)
- Príncia Grejo Setti
- Departamento de Genética e Evolução, Universidade Federal de São Carlos, 13565-905, São Carlos, SP, Brazil
| | - Geize Aparecida Deon
- Departamento de Genética e Evolução, Universidade Federal de São Carlos, 13565-905, São Carlos, SP, Brazil
| | | | | | - Analía Del Valle Garnero
- Campus São Gabriel, Universidade Federal do Pampa, 97307-020, São Gabriel, Rio Grande do Sul, Brazil
| | - Ricardo José Gunski
- Campus São Gabriel, Universidade Federal do Pampa, 97307-020, São Gabriel, Rio Grande do Sul, Brazil
| | - Edivaldo Herculano Corrêa de Oliveira
- Laboratório de Citogenômica e Mutagênese Ambiental, Seção de Meio Ambiente, Instituto Evandro Chagas, 67030-000, Ananindeua, PA, Brazil
- Instituto de Ciências Exatas e Naturais, Universidade Federal do Pará, 66075-110, Belém, PA, Brazil
| | - Fábio Porto-Foresti
- Faculdade de Ciências, Universidade Estadual Paulista, 17033-360, Bauru, São Paulo, Brazil
| | | | - Fábio Augusto Oliveira Silva
- Laboratório de Citogenômica e Mutagênese Ambiental, Seção de Meio Ambiente, Instituto Evandro Chagas, 67030-000, Ananindeua, PA, Brazil
| | - Thomas Liehr
- Institute of Human Genetics, Jena University Hospital, Friedrich Schiller University, 07747, Jena, Germany.
| | - Ricardo Utsunomia
- Faculdade de Ciências, Universidade Estadual Paulista, 17033-360, Bauru, São Paulo, Brazil
| | - Rafael Kretschmer
- Departamento de Ecologia, Zoologia e Genética, Instituto de Biologia, Universidade Federal de Pelotas, 96.010-610, Pelotas, RS, Brazil
| | - Marcelo de Bello Cioffi
- Departamento de Genética e Evolução, Universidade Federal de São Carlos, 13565-905, São Carlos, SP, Brazil
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O’Connor RE, Kretschmer R, Romanov MN, Griffin DK. A Bird's-Eye View of Chromosomic Evolution in the Class Aves. Cells 2024; 13:310. [PMID: 38391923 PMCID: PMC10886771 DOI: 10.3390/cells13040310] [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: 12/05/2023] [Revised: 01/27/2024] [Accepted: 02/05/2024] [Indexed: 02/24/2024] Open
Abstract
Birds (Aves) are the most speciose of terrestrial vertebrates, displaying Class-specific characteristics yet incredible external phenotypic diversity. Critical to agriculture and as model organisms, birds have adapted to many habitats. The only extant examples of dinosaurs, birds emerged ~150 mya and >10% are currently threatened with extinction. This review is a comprehensive overview of avian genome ("chromosomic") organization research based mostly on chromosome painting and BAC-based studies. We discuss traditional and contemporary tools for reliably generating chromosome-level assemblies and analyzing multiple species at a higher resolution and wider phylogenetic distance than previously possible. These results permit more detailed investigations into inter- and intrachromosomal rearrangements, providing unique insights into evolution and speciation mechanisms. The 'signature' avian karyotype likely arose ~250 mya and remained largely unchanged in most groups including extinct dinosaurs. Exceptions include Psittaciformes, Falconiformes, Caprimulgiformes, Cuculiformes, Suliformes, occasional Passeriformes, Ciconiiformes, and Pelecaniformes. The reasons for this remarkable conservation may be the greater diploid chromosome number generating variation (the driver of natural selection) through a greater possible combination of gametes and/or an increase in recombination rate. A deeper understanding of avian genomic structure permits the exploration of fundamental biological questions pertaining to the role of evolutionary breakpoint regions and homologous synteny blocks.
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Affiliation(s)
- Rebecca E. O’Connor
- School of Biosciences, University of Kent, Canterbury CT2 7NJ, UK; (R.E.O.); (M.N.R.)
| | - Rafael Kretschmer
- Departamento de Ecologia, Zoologia e Genética, Instituto de Biologia, Campus Universitário Capão do Leão, Universidade Federal de Pelotas, Pelotas 96010-900, RS, Brazil;
| | - Michael N. Romanov
- School of Biosciences, University of Kent, Canterbury CT2 7NJ, UK; (R.E.O.); (M.N.R.)
- L. K. Ernst Federal Research Centre for Animal Husbandry, Dubrovitsy, 142132 Podolsk, Moscow Oblast, Russia
| | - Darren K. Griffin
- School of Biosciences, University of Kent, Canterbury CT2 7NJ, UK; (R.E.O.); (M.N.R.)
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de Oliveira MPB, Kretschmer R, Deon GA, Toma GA, Ezaz T, Goes CAG, Porto-Foresti F, Liehr T, Utsunomia R, Cioffi MDB. Following the Pathway of W Chromosome Differentiation in Triportheus (Teleostei: Characiformes). BIOLOGY 2023; 12:1114. [PMID: 37626998 PMCID: PMC10452202 DOI: 10.3390/biology12081114] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/29/2023] [Revised: 08/04/2023] [Accepted: 08/08/2023] [Indexed: 08/27/2023]
Abstract
In this work, we trace the dynamics of satellite DNAs (SatDNAs) accumulation and elimination along the pathway of W chromosome differentiation using the well-known Triportheus fish model. Triportheus stands out due to a conserved ZZ/ZW sex chromosome system present in all examined species. While the Z chromosome is conserved in all species, the W chromosome is invariably smaller and exhibits differences in size and morphology. The presumed ancestral W chromosome is comparable to that of T. auritus, and contains 19 different SatDNA families. Here, by examining five additional Triportheus species, we showed that the majority of these repetitive sequences were eliminated as speciation was taking place. The W chromosomes continued degeneration, while the Z chromosomes of some species began to accumulate some TauSatDNAs. Additional species-specific SatDNAs that made up the heterochromatic region of both Z and W chromosomes were most likely amplified in each species. Therefore, the W chromosomes of the various Triportheus species have undergone significant evolutionary changes in a short period of time (15-25 Myr) after their divergence.
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Affiliation(s)
| | - Rafael Kretschmer
- Departamento de Ecologia, Zoologia e Genética, Instituto de Biologia, Universidade Federal de Pelotas, Pelotas 96010-610, Brazil;
| | - Geize Aparecida Deon
- Departamento de Genética e Evolução, Universidade Federal de São Carlos, Sao Carlos 13565-905, Brazil; (M.P.B.d.O.); (G.A.D.); (G.A.T.); (M.d.B.C.)
| | - Gustavo Akira Toma
- Departamento de Genética e Evolução, Universidade Federal de São Carlos, Sao Carlos 13565-905, Brazil; (M.P.B.d.O.); (G.A.D.); (G.A.T.); (M.d.B.C.)
| | - Tariq Ezaz
- Faculty of Science and Technology, Centre for Conservation Ecology and Genomics, University of Canberra, Canberra 2617, Australia;
| | - Caio Augusto Gomes Goes
- Faculdade de Ciências, Universidade Estadual Paulista, Bauru 13506-900, Brazil; (C.A.G.G.); (F.P.-F.); (R.U.)
| | - Fábio Porto-Foresti
- Faculdade de Ciências, Universidade Estadual Paulista, Bauru 13506-900, Brazil; (C.A.G.G.); (F.P.-F.); (R.U.)
| | - Thomas Liehr
- Institute of Human Genetics, University Hospital Jena, 07747 Jena, Germany
| | - Ricardo Utsunomia
- Faculdade de Ciências, Universidade Estadual Paulista, Bauru 13506-900, Brazil; (C.A.G.G.); (F.P.-F.); (R.U.)
| | - Marcelo de Bello Cioffi
- Departamento de Genética e Evolução, Universidade Federal de São Carlos, Sao Carlos 13565-905, Brazil; (M.P.B.d.O.); (G.A.D.); (G.A.T.); (M.d.B.C.)
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5
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Charlesworth D. Why and how do Y chromosome stop recombining? J Evol Biol 2023; 36:632-636. [PMID: 36683363 DOI: 10.1111/jeb.14137] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2022] [Revised: 11/21/2022] [Accepted: 11/24/2022] [Indexed: 01/24/2023]
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Hearn KE, Koch EL, Stankowski S, Butlin RK, Faria R, Johannesson K, Westram AM. Differing associations between sex determination and sex‐linked inversions in two ecotypes of
Littorina saxatilis. Evol Lett 2022; 6:358-374. [PMID: 36254259 PMCID: PMC9554762 DOI: 10.1002/evl3.295] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2022] [Revised: 07/07/2022] [Accepted: 07/20/2022] [Indexed: 12/14/2022] Open
Abstract
Sexual antagonism is a common hypothesis for driving the evolution of sex chromosomes, whereby recombination suppression is favored between sexually antagonistic loci and the sex‐determining locus to maintain beneficial combinations of alleles. This results in the formation of a sex‐determining region. Chromosomal inversions may contribute to recombination suppression but their precise role in sex chromosome evolution remains unclear. Because local adaptation is frequently facilitated through the suppression of recombination between adaptive loci by chromosomal inversions, there is potential for inversions that cover sex‐determining regions to be involved in local adaptation as well, particularly if habitat variation creates environment‐dependent sexual antagonism. With these processes in mind, we investigated sex determination in a well‐studied example of local adaptation within a species: the intertidal snail, Littorina saxatilis. Using SNP data from a Swedish hybrid zone, we find novel evidence for a female‐heterogametic sex determination system that is restricted to one ecotype. Our results suggest that four putative chromosomal inversions, two previously described and two newly discovered, span the putative sex chromosome pair. We determine their differing associations with sex, which suggest distinct strata of differing ages. The same inversions are found in the second ecotype but do not show any sex association. The striking disparity in inversion‐sex associations between ecotypes that are connected by gene flow across a habitat transition that is just a few meters wide indicates a difference in selective regime that has produced a distinct barrier to the spread of the newly discovered sex‐determining region between ecotypes. Such sex chromosome‐environment interactions have not previously been uncovered in L. saxatilis and are known in few other organisms. A combination of both sex‐specific selection and divergent natural selection is required to explain these highly unusual patterns.
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Affiliation(s)
- Katherine E. Hearn
- Ecology and Evolutionary Biology, School of Biosciences University of Sheffield Sheffield S10 2TN United Kingdom
| | - Eva L. Koch
- Ecology and Evolutionary Biology, School of Biosciences University of Sheffield Sheffield S10 2TN United Kingdom
- Department of Zoology University of Cambridge Cambridge CB2 3EJ United Kingdom
| | - Sean Stankowski
- Ecology and Evolutionary Biology, School of Biosciences University of Sheffield Sheffield S10 2TN United Kingdom
- ISTA (Institute of Science and Technology Austria) Klosterneuburg 3400 Austria
| | - Roger K. Butlin
- Ecology and Evolutionary Biology, School of Biosciences University of Sheffield Sheffield S10 2TN United Kingdom
- Department of Marine Sciences University of Gothenburg Strömstad SE‐45296 Sweden
| | - Rui Faria
- CIBIO, Centro de Investigação em Biodiversidade e Recursos Genéticos, InBIO Laboratório Associado Campus de Vairão, Universidade do Porto Vairão 4485‐661 Portugal
- BIOPOLIS Program in Genomics, Biodiversity and Land Planning, CIBIO Campus de Vairão, Universidade do Porto Vairão 4485‐661 Portugal
| | - Kerstin Johannesson
- Department of Marine Sciences University of Gothenburg Strömstad SE‐45296 Sweden
| | - Anja M. Westram
- ISTA (Institute of Science and Technology Austria) Klosterneuburg 3400 Austria
- Faculty of Biosciences and Aquaculture Nord University Bodø 8026 Norway
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7
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de Manuel M, Wu FL, Przeworski M. A paternal bias in germline mutation is widespread in amniotes and can arise independently of cell divisions. eLife 2022; 11:80008. [PMID: 35916372 PMCID: PMC9439683 DOI: 10.7554/elife.80008] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2022] [Accepted: 08/01/2022] [Indexed: 11/13/2022] Open
Abstract
In humans and other mammals, germline mutations are more likely to arise in fathers than in mothers. Although this sex bias has long been attributed to DNA replication errors in spermatogenesis, recent evidence from humans points to the importance of mutagenic processes that do not depend on cell division, calling into question our understanding of this basic phenomenon. Here, we infer the ratio of paternal-to-maternal mutations, α, in 42 species of amniotes, from putatively neutral substitution rates of sex chromosomes and autosomes. Despite marked differences in gametogenesis, physiologies and environments across species, fathers consistently contribute more mutations than mothers in all the species examined, including mammals, birds, and reptiles. In mammals, α is as high as 4 and correlates with generation times; in birds and snakes, α appears more stable around 2. These observations are consistent with a simple model, in which mutations accrue at equal rates in both sexes during early development and at a higher rate in the male germline after sexual differentiation, with a conserved paternal-to-maternal ratio across species. Thus, α may reflect the relative contributions of two or more developmental phases to total germline mutations, and is expected to depend on generation time even if mutations do not track cell divisions.
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Affiliation(s)
- Marc de Manuel
- Department of Biological Sciences, Columbia University, New York, United States
| | - Felix L Wu
- Department of Biological Sciences, Columbia University, New York, United States
| | - Molly Przeworski
- Department of Systems Biology, Columbia University, New York, United States
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8
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Dynamic Patterns of Sex Chromosome Evolution in Neognath Birds: Many Independent Barriers to Recombination at the ATP5F1A Locus. BIRDS 2022. [DOI: 10.3390/birds3010004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
Avian sex chromosomes evolved after the divergence of birds and crocodilians from their common ancestor, so they are younger than the better-studied chromosomes of mammals. It has long been recognized that there may have been several stages to the evolution of avian sex chromosomes. For example, the CHD1 undergoes recombination in paleognaths but not neognaths. Genome assemblies have suggested that there may be variation in the timing of barriers to recombination among Neognathae, but there remains little understanding of the extent of this variability. Here, we look at partial sequences of ATP5F1A, which is on the avian Z and W chromosomes. It is known that recombination of this gene has independently ceased in Galliformes, Anseriformes, and at least five neoavian orders, but whether there are other independent cessations of recombination among Neoaves is not understood. We analyzed a combination of data extracted from published chromosomal-level genomes with data collected using PCR and cloning to identify Z and W copies in 22 orders. Our results suggest that there may be at least 19 independent cessations of recombination within Neognathae, and 3 clades that may still be undergoing recombination (or have only recently ceased recombination). Analyses of ATP5F1A protein sequences revealed an increased amino acid substitution rate for W chromosome gametologs, suggesting relaxed purifying selection on the W chromosome. Supporting this hypothesis, we found that the increased substitution rate was particularly pronounced for buried residues, which are expected to be more strongly constrained by purifying selection. This highlights the dynamic nature of avian sex chromosomes, and that this level of variation among clades means they should be a good system to understand sex chromosome evolution.
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9
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Termignoni-Garcia F, Kirchman JJ, Clark J, Edwards SV. Comparative Population Genomics of Cryptic Speciation and Adaptive Divergence in Bicknell's and Gray-Cheeked Thrushes (Aves: Catharus bicknelli and Catharus minimus). Genome Biol Evol 2022; 14:evab255. [PMID: 34999784 PMCID: PMC8743040 DOI: 10.1093/gbe/evab255] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 11/10/2021] [Indexed: 02/07/2023] Open
Abstract
Cryptic speciation may occur when reproductive isolation is recent or the accumulation of morphological differences between sister lineages is slowed by stabilizing selection preventing phenotypic differentiation. In North America, Bicknell's Thrush (Catharus bicknelli) and its sister species, the Gray-cheeked Thrush (Catharus minimus), are parapatrically breeding migratory songbirds, distinguishable in nature only by subtle differences in song and coloration, and were recognized as distinct species only in the 1990s. Previous molecular studies have estimated that the species diverged approximately 120,000-420,000 YBP and found very low levels of introgression despite their similarity and sympatry in the spring (prebreeding) migration. To further clarify the history, genetic divergence, genomic structure, and adaptive processes in C. bicknelli and C. minimus, we sequenced and assembled high-coverage reference genomes of both species and resequenced genomes from population samples of C. bicknelli, C. minimus, and two individuals of the Swainson's Thrush (Catharus ustulatus). The genome of C. bicknelli exhibits markedly higher abundances of transposable elements compared with other Catharus and chicken. Demographic and admixture analyses confirm moderate genome-wide differentiation (Fst ≈ 0.10) and limited gene flow between C. bicknelli and C. minimus, but suggest a more recent divergence than estimates based on mtDNA. We find evidence of rapid evolution of the Z-chromosome and elevated divergence consistent with natural selection on genomic regions near genes involved with neuronal processes in C. bicknelli. These genomes are a useful resource for future investigations of speciation, migration, and adaptation in Catharus thrushes.
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Affiliation(s)
- Flavia Termignoni-Garcia
- Department of Organismic and Evolutionary Biology and Museum of Comparative Zoology, Harvard University, Cambridge, Massachusetts, USA
| | | | - Johnathan Clark
- Department of Organismic and Evolutionary Biology and Museum of Comparative Zoology, Harvard University, Cambridge, Massachusetts, USA
| | - Scott V Edwards
- Department of Organismic and Evolutionary Biology and Museum of Comparative Zoology, Harvard University, Cambridge, Massachusetts, USA
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10
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Mongue AJ, Hansen ME, Walters JR. Support for faster and more adaptive Z chromosome evolution in two divergent lepidopteran lineages. Evolution 2021; 76:332-345. [PMID: 34463346 PMCID: PMC9291949 DOI: 10.1111/evo.14341] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2021] [Revised: 07/21/2021] [Accepted: 08/06/2021] [Indexed: 12/14/2022]
Abstract
The rateof divergence for Z or X chromosomes is usually observed to be greater than autosomes, but the proposed evolutionary causes for this pattern vary, as do empirical results from diverse taxa. Even among moths and butterflies (Lepidoptera), which generally share a single-origin Z chromosome, the handful of available studies give mixed support for faster or more adaptive evolution of the Z chromosome, depending on the species assayed. Here, we examine the molecular evolution of Z chromosomes in two additional lepidopteran species: the Carolina sphinx moth and the monarch butterfly, the latter of which possesses a recent chromosomal fusion yielding a segment of newly Z-linked DNA. We find evidence for both faster and more adaptive Z chromosome evolution in both species, although this effect is strongest in the neo-Z portion of the monarch sex chromosome. The neo-Z is less male-biased than expected of a Z chromosome, and unbiased and female-biased genes drive the signal for adaptive evolution here. Together these results suggest that male-biased gene accumulation and haploid selection have opposing effects on long-term rates of adaptation and may help explain the discrepancies in previous findings as well as the repeated evolution of neo-sex chromosomes in Lepidoptera.
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Affiliation(s)
- Andrew J Mongue
- Department of Ecology and Evolutionary Biology, University of Kansas, Lawrence, Kansas, 66045.,Institute of Evolutionary Biology, University of Edinburgh, Edinburgh, EH93FL, United Kingdom
| | - Megan E Hansen
- Department of Ecology and Evolutionary Biology, University of Kansas, Lawrence, Kansas, 66045
| | - James R Walters
- Department of Ecology and Evolutionary Biology, University of Kansas, Lawrence, Kansas, 66045
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11
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Alfonso C, Jones BC, Vernasco BJ, Moore IT. Integrative Studies of Sexual Selection in Manakins, a Clade of Charismatic Tropical Birds. Integr Comp Biol 2021; 61:1267-1280. [PMID: 34251421 DOI: 10.1093/icb/icab158] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2021] [Revised: 05/07/2021] [Accepted: 07/07/2021] [Indexed: 11/14/2022] Open
Abstract
The neotropical manakins (family Pipridae) provide a great opportunity for integrative studies of sexual selection as nearly all of the 51 species are lek-breeding, an extreme form of polygyny, and highly sexually dimorphic both in appearance and behavior. Male courtship displays are often elaborate and include auditory cues, both vocal and mechanical, as well as visual elements. In addition, the displays are often extremely rapid, highly acrobatic, and, in some species, multiple males perform coordinated displays that form the basis of long-term coalitions. Male manakins also exhibit unique neuroendocrine, physiological, and anatomical adaptations to support the performance of these complex displays and the maintenance of their intricate social systems. The Manakin Genomics Research Coordination Network (Manakin RCN, https://www.manakinsrcn.org) has brought together researchers (many in this symposium and this issue) from across disciplines to address the implications of sexual selection on evolution, ecology, behavior, and physiology in manakins. The objective of this paper is to present some of the most pertinent and integrative manakin research as well as introducing the papers presented in this issue. The results discussed at the manakin symposium, part of the 2021 Society for Integrative and Comparative Biology Conference, highlight the remarkable genomic, behavioral, and physiological adaptations as well as the evolutionary causes and consequences of strong sexual selection pressures that are evident in manakins.
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Affiliation(s)
- Camilo Alfonso
- Department of Biological Sciences, Virginia Tech, Blacksburg, VA 24061, USA
| | - Blake C Jones
- Science and Mathematics, Bennington College, 1 College Dr., Bennington, VT 05201, USA
| | - Ben J Vernasco
- School of Biological Sciences, Washington State University, Pullman, WA, USA
| | - Ignacio T Moore
- Department of Biological Sciences, Virginia Tech, Blacksburg, VA 24061, USA
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12
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Schield DR, Perry BW, Nikolakis ZL, Mackessy SP, Castoe TA. Population Genomic Analyses Confirm Male-Biased Mutation Rates in Snakes. J Hered 2021; 112:221-227. [PMID: 33502475 DOI: 10.1093/jhered/esab005] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2020] [Accepted: 01/21/2021] [Indexed: 11/13/2022] Open
Abstract
Male-biased mutation rates occur in a diverse array of organisms. The ratio of male-to-female mutation rate may have major ramifications for evolution across the genome, and for sex-linked genes in particular. In ZW species, the Z chromosome is carried by males two-thirds of the time, leading to the prediction that male-biased mutation rates will have a disproportionate effect on the evolution of Z-linked genes relative to autosomes and the W chromosome. Colubroid snakes (including colubrids, elapids, and viperids) have ZW sex determination, yet male-biased mutation rates have not been well studied in this group. Here we analyze a population genomic dataset from rattlesnakes to quantify genetic variation within and genetic divergence between species. We use a new method for unbiased estimation of population genetic summary statistics to compare variation between the Z chromosome and autosomes and to calculate net nucleotide differentiation between species. We find evidence for a 2.03-fold greater mutation rate in male rattlesnakes relative to females, corresponding to an average μZ/μA ratio of 1.1. Our results from snakes are quantitatively similar to birds, suggesting that male-biased mutation rates may be a common feature across vertebrate lineages with ZW sex determination.
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Affiliation(s)
- Drew R Schield
- Department of Biology, University of Texas at Arlington, Arlington, TX.,Department of Ecology and Evolutionary Biology, University of Colorado Boulder, Boulder, CO
| | - Blair W Perry
- Department of Biology, University of Texas at Arlington, Arlington, TX
| | | | - Stephen P Mackessy
- School of Biological Sciences, University of Northern Colorado, Greeley, CO
| | - Todd A Castoe
- Department of Biology, University of Texas at Arlington, Arlington, TX
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13
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Schield DR, Scordato ESC, Smith CCR, Carter JK, Cherkaoui SI, Gombobaatar S, Hajib S, Hanane S, Hund AK, Koyama K, Liang W, Liu Y, Magri N, Rubtsov A, Sheta B, Turbek SP, Wilkins MR, Yu L, Safran RJ. Sex-linked genetic diversity and differentiation in a globally distributed avian species complex. Mol Ecol 2021; 30:2313-2332. [PMID: 33720472 DOI: 10.1111/mec.15885] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2020] [Revised: 02/19/2021] [Accepted: 03/10/2021] [Indexed: 12/15/2022]
Abstract
Sex chromosomes often bear distinct patterns of genetic variation due to unique patterns of inheritance and demography. The processes of mutation, recombination, genetic drift and selection also influence rates of evolution on sex chromosomes differently than autosomes. Measuring such differences provides information about how these processes shape genomic variation and their roles in the origin of species. To test hypotheses and predictions about patterns of autosomal and sex-linked genomic diversity and differentiation, we measured population genetic statistics within and between populations and subspecies of the barn swallow (Hirundo rustica) and performed explicit comparisons between autosomal and Z-linked genomic regions. We first tested for evidence of low Z-linked genetic diversity and high Z-linked population differentiation relative to autosomes, then for evidence that the Z chromosome bears greater ancestry information due to faster lineage sorting. Finally, we investigated geographical clines across hybrid zones for evidence that the Z chromosome is resistant to introgression due to selection against hybrids. We found evidence that the barn swallow mating system, demographic history and linked selection each contribute to low Z-linked diversity and high Z-linked differentiation. While incomplete lineage sorting is rampant across the genome, our results indicate faster sorting of ancestral polymorphism on the Z. Finally, hybrid zone analyses indicate barriers to introgression on the Z chromosome, suggesting that sex-linked traits are important in reproductive isolation, especially in migratory divide regions. Our study highlights how selection, gene flow and demography shape sex-linked genetic diversity and underlines the relevance of the Z chromosome in speciation.
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Affiliation(s)
- Drew R Schield
- Department of Ecology and Evolutionary Biology, University of Colorado, Boulder, CO, USA
| | - Elizabeth S C Scordato
- Department of Ecology and Evolutionary Biology, University of Colorado, Boulder, CO, USA.,Department of Biological Sciences, California State Polytechnic University, Pomona, CA, USA
| | - Chris C R Smith
- Department of Ecology and Evolutionary Biology, University of Colorado, Boulder, CO, USA
| | - Javan K Carter
- Department of Ecology and Evolutionary Biology, University of Colorado, Boulder, CO, USA
| | - Sidi Imad Cherkaoui
- Ecole Supérieure de Technologie de Khénifra, Sultan Moulay Slimane University, Béni-Mellal, Morocco
| | - Sundev Gombobaatar
- National University of Mongolia and Mongolian Ornithological Society, Ulaanbaatar, Mongolia
| | - Said Hajib
- Water and Forests Department, Forest Research Center, Rabat-Agdal, Morocco
| | - Saad Hanane
- Water and Forests Department, Forest Research Center, Rabat-Agdal, Morocco
| | - Amanda K Hund
- Department of Ecology and Evolutionary Biology, University of Colorado, Boulder, CO, USA.,Department of Ecology, Evolution, and Behavior, University of Minnesota, St. Paul, MN, USA
| | | | - Wei Liang
- Ministry of Education Key Laboratory for Ecology of Tropical Islands, Key Laboratory of Tropical Animal and Plant Ecology of Hainan Province, College of Life Sciences, Hainan Normal University, Haikou, China
| | - Yang Liu
- State Key Laboratory of Biocontrol, School of Ecology, Sun Yat-sen University, Guangzhou, China
| | - Najib Magri
- Water and Forests Department, Forest Research Center, Rabat-Agdal, Morocco
| | | | - Basma Sheta
- Zoology Department, Faculty of Science, Damietta University, New Damietta City, Egypt
| | - Sheela P Turbek
- Department of Ecology and Evolutionary Biology, University of Colorado, Boulder, CO, USA
| | - Matthew R Wilkins
- Department of Ecology and Evolutionary Biology, University of Colorado, Boulder, CO, USA.,Collaborative for STEM Education and Outreach, Vanderbilt University, Nashville, TN, USA
| | - Liu Yu
- Key Laboratory for Biodiversity Sciences and Ecological Engineering, Ministry of Education, College of Life Sciences, Beijing Normal University, Beijing, China
| | - Rebecca J Safran
- Department of Ecology and Evolutionary Biology, University of Colorado, Boulder, CO, USA
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14
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Liu J, Wang Z, Li J, Xu L, Liu J, Feng S, Guo C, Chen S, Ren Z, Rao J, Wei K, Chen Y, Jarvis ED, Zhang G, Zhou Q. A new emu genome illuminates the evolution of genome configuration and nuclear architecture of avian chromosomes. Genome Res 2021; 31:497-511. [PMID: 33408157 PMCID: PMC7919449 DOI: 10.1101/gr.271569.120] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2020] [Accepted: 12/30/2020] [Indexed: 01/30/2023]
Abstract
Emu and other ratites are more informative than any other birds in reconstructing the evolution of the ancestral avian or vertebrate karyotype because of their much slower rate of genome evolution. Here, we generated a new chromosome-level genome assembly of a female emu, and estimated the tempo of chromosome evolution across major avian phylogenetic branches, by comparing it to chromosome-level genome assemblies of 11 other bird and one turtle species. We found ratites exhibited the lowest numbers of intra- and inter-chromosomal changes among birds since their divergence with turtles. The small-sized and gene-rich emu microchromosomes have frequent inter-chromosomal contacts that are associated with housekeeping genes, which appears to be driven by clustering their centromeres in the nuclear interior, away from the macrochromosomes in the nuclear periphery. Unlike nonratite birds, only less than one-third of the emu W Chromosome regions have lost homologous recombination and diverged between the sexes. The emu W is demarcated into a highly heterochromatic region (WS0) and another recently evolved region (WS1) with only moderate sequence divergence with the Z Chromosome. WS1 has expanded its inactive chromatin compartment, increased chromatin contacts within the region, and decreased contacts with the nearby regions, possibly influenced by the spreading of heterochromatin from WS0. These patterns suggest that alteration of chromatin conformation comprises an important early step of sex chromosome evolution. Overall, our results provide novel insights into the evolution of avian genome structure and sex chromosomes in three-dimensional space.
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Affiliation(s)
- Jing Liu
- MOE Laboratory of Biosystems Homeostasis & Protection and Zhejiang Provincial Key Laboratory for Cancer Molecular Cell Biology, Life Sciences Institute, Zhejiang University, Hangzhou 310058, China
- Department of Neuroscience and Developmental Biology, University of Vienna, Vienna 1090, Austria
| | - Zongji Wang
- MOE Laboratory of Biosystems Homeostasis & Protection and Zhejiang Provincial Key Laboratory for Cancer Molecular Cell Biology, Life Sciences Institute, Zhejiang University, Hangzhou 310058, China
- Department of Neuroscience and Developmental Biology, University of Vienna, Vienna 1090, Austria
- Institute of Animal Sex and Development, Zhejiang Wanli University, Ningbo 315100, China
| | - Jing Li
- MOE Laboratory of Biosystems Homeostasis & Protection and Zhejiang Provincial Key Laboratory for Cancer Molecular Cell Biology, Life Sciences Institute, Zhejiang University, Hangzhou 310058, China
| | - Luohao Xu
- Department of Neuroscience and Developmental Biology, University of Vienna, Vienna 1090, Austria
| | - Jiaqi Liu
- Wuhan Gooalgene Technology Company, Wuhan 430070, China
| | - Shaohong Feng
- BGI-Shenzhen, Beishan Industrial Zone, Shenzhen 518083, China
| | - Chunxue Guo
- BGI-Shenzhen, Beishan Industrial Zone, Shenzhen 518083, China
| | - Shengchan Chen
- Longteng Ecological Culture Company, Limited, Zhashui 711400, China
| | - Zhanjun Ren
- Key Laboratory of Animal Genetics, Breeding and Reproduction of Shaanxi Province, College of Animal Science and Technology, Northwest A&F University, Yangling 712100, China
| | - Jinpeng Rao
- Center for Reproductive Medicine, The 2nd Affiliated Hospital, School of Medicine, Zhejiang University, Hangzhou 310052, China
| | - Kai Wei
- Center for Reproductive Medicine, The 2nd Affiliated Hospital, School of Medicine, Zhejiang University, Hangzhou 310052, China
| | - Yuezhou Chen
- Jianzhou Poultry Industry Company, Limited, Yong'an 366000, China
| | - Erich D Jarvis
- Laboratory of Neurogenetics of Language, The Rockefeller University, New York, New York 10065, USA
- Howard Hughes Medical Institute, Chevy Chase, Maryland 20815, USA
| | - Guojie Zhang
- China National GeneBank, BGI-Shenzhen, Shenzhen 518120, China
- State Key Laboratory of Genetic Resources and Evolution, Kunming Institute of Zoology, Chinese Academy of Sciences, Kunming 650223, China
- Section for Ecology and Evolution, Department of Biology, University of Copenhagen, DK-2100 Copenhagen, Denmark
- Center for Excellence in Animal Evolution and Genetics, Chinese Academy of Sciences, Kunming 650223, China
| | - Qi Zhou
- MOE Laboratory of Biosystems Homeostasis & Protection and Zhejiang Provincial Key Laboratory for Cancer Molecular Cell Biology, Life Sciences Institute, Zhejiang University, Hangzhou 310058, China
- Department of Neuroscience and Developmental Biology, University of Vienna, Vienna 1090, Austria
- Center for Reproductive Medicine, The 2nd Affiliated Hospital, School of Medicine, Zhejiang University, Hangzhou 310052, China
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15
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Hayes K, Barton HJ, Zeng K. A Study of Faster-Z Evolution in the Great Tit (Parus major). Genome Biol Evol 2021; 12:210-222. [PMID: 32119100 PMCID: PMC7144363 DOI: 10.1093/gbe/evaa044] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 02/26/2020] [Indexed: 12/17/2022] Open
Abstract
Sex chromosomes contribute substantially to key evolutionary processes such as speciation and adaptation. Several theories suggest that evolution could occur more rapidly on sex chromosomes, but currently our understanding of whether and how this occurs is limited. Here, we present an analysis of the great tit (Parus major) genome, aiming to detect signals of faster-Z evolution. We find mixed evidence of faster divergence on the Z chromosome than autosomes, with significantly higher divergence being found in ancestral repeats, but not at 4- or 0-fold degenerate sites. Interestingly, some 4-fold sites appear to be selectively constrained, which may mislead analyses that use these sites as the neutral reference (e.g., dN/dS). Consistent with other studies in birds, the mutation rate is significantly higher in males than females, and the long-term Z-to-autosome effective population size ratio is only 0.5, significantly lower than the expected value of 0.75. These are indicative of male-driven evolution and high variance in male reproductive success, respectively. We find no evidence for an increased efficacy of positive selection on the Z chromosome. In contrast, the Z chromosome in great tits appears to be affected by increased genetic drift, which has led to detectable signals of weakened intensity of purifying selection. These results provide further evidence that the Z chromosome often has a low effective population size, and that this has important consequences for its evolution. They also highlight the importance of considering multiple factors that can affect the rate of evolution and effective population sizes of sex chromosomes.
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Affiliation(s)
- Kai Hayes
- Department of Animal and Plant Sciences, University of Sheffield, United Kingdom
| | - Henry J Barton
- Department of Animal and Plant Sciences, University of Sheffield, United Kingdom.,Organismal and Evolutionary Biology Research Program, University of Helsinki, Finland
| | - Kai Zeng
- Department of Animal and Plant Sciences, University of Sheffield, United Kingdom
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16
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He C, Zhao L, Xiao L, Xu K, Ding J, Zhou H, Zheng Y, Han C, Akinyemi F, Luo H, Yang L, Luo L, Yuan H, Lu X, Meng H. Chromosome level assembly reveals a unique immune gene organization and signatures of evolution in the common pheasant. Mol Ecol Resour 2020; 21:897-911. [PMID: 33188724 DOI: 10.1111/1755-0998.13296] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2020] [Revised: 11/03/2020] [Accepted: 11/06/2020] [Indexed: 12/30/2022]
Abstract
The common pheasant Phasianus colchicus, belonging to the order Galliformes and family Phasianidae, is the most widespread species. Despite a long history of captivity, the domestication of this bird is still at a preliminary stage. Recently, the demand for accelerating its transformation to poultry for meat and egg production has been increasing. In this study, we assembled high quality, chromosome scale genome of the common pheasant by using PacBio long reads, next-generation short reads, and Hi-C technology. The primary assembly has contig N50 size of 1.33 Mb and scaffold N50 size of 59.46 Mb, with a total size of 0.99 Gb, resolving most macrochromosomes into single scaffolds. A total of 23,058 genes and 10.71 Mb interspersed repeats were identified, constituting 30.31% and 10.71% of the common pheasant genome, respectively. Our phylogenetic analysis revealed that the common pheasant shared common ancestors with turkey about 24.7-34.5 million years ago (Ma). Rapidly evolved gene families, as well as branch-specific positively selected genes, indicate that calcium-related genes are potentially related to the adaptive and evolutionary change of the common pheasant. Interestingly, we found that the common pheasant has a unique major histocompatibility complex B locus (MHC-B) structure: three major inversions occurred in the sequence compared with chicken MHC-B. Furthermore, we detected signals of selection in five breeds of domestic common pheasant, several of which are production-oriented.
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Affiliation(s)
- Chuan He
- Shanghai Key Laboratory of Veterinary Biotechnology, School of Agriculture and Biology, Shanghai Jiao Tong University, Shanghai, China
| | - Lele Zhao
- Shanghai Animal Disease Control Center, Shanghai, China
| | - Lu Xiao
- Shanghai Key Laboratory of Veterinary Biotechnology, School of Agriculture and Biology, Shanghai Jiao Tong University, Shanghai, China
| | - Ke Xu
- Shanghai Key Laboratory of Veterinary Biotechnology, School of Agriculture and Biology, Shanghai Jiao Tong University, Shanghai, China
| | - Jinmei Ding
- Shanghai Key Laboratory of Veterinary Biotechnology, School of Agriculture and Biology, Shanghai Jiao Tong University, Shanghai, China
| | - Hao Zhou
- Shanghai Key Laboratory of Veterinary Biotechnology, School of Agriculture and Biology, Shanghai Jiao Tong University, Shanghai, China
| | - Yuming Zheng
- Shanghai Key Laboratory of Veterinary Biotechnology, School of Agriculture and Biology, Shanghai Jiao Tong University, Shanghai, China
| | - Chengxiao Han
- Shanghai Key Laboratory of Veterinary Biotechnology, School of Agriculture and Biology, Shanghai Jiao Tong University, Shanghai, China
| | - Fisayo Akinyemi
- Shanghai Key Laboratory of Veterinary Biotechnology, School of Agriculture and Biology, Shanghai Jiao Tong University, Shanghai, China
| | - Huaixi Luo
- Shanghai Key Laboratory of Veterinary Biotechnology, School of Agriculture and Biology, Shanghai Jiao Tong University, Shanghai, China
| | - Lingyu Yang
- Shanghai Key Laboratory of Veterinary Biotechnology, School of Agriculture and Biology, Shanghai Jiao Tong University, Shanghai, China
| | - Lingxiao Luo
- Shanghai Key Laboratory of Veterinary Biotechnology, School of Agriculture and Biology, Shanghai Jiao Tong University, Shanghai, China
| | - Hongyan Yuan
- Shanghai Xinhao Rare Poultry Breeding Co. Ltd., Shanghai, China
| | - Xuelin Lu
- Shanghai Animal Disease Control Center, Shanghai, China
| | - He Meng
- Shanghai Key Laboratory of Veterinary Biotechnology, School of Agriculture and Biology, Shanghai Jiao Tong University, Shanghai, China
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17
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Charlesworth D, Bergero R, Graham C, Gardner J, Yong L. Locating the Sex Determining Region of Linkage Group 12 of Guppy ( Poecilia reticulata). G3 (BETHESDA, MD.) 2020; 10:3639-3649. [PMID: 32753367 PMCID: PMC7534449 DOI: 10.1534/g3.120.401573] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/03/2020] [Accepted: 07/29/2020] [Indexed: 01/04/2023]
Abstract
Despite over 100 years of study, the location of the fully sex-linked region of the guppy (Poecilia reticulata) carrying the male-determining locus, and the regions where the XY pair recombine, remain unclear. Previous population genomics studies to determine these regions used small samples from recently bottlenecked captive populations, which increase the false positive rate of associations between individuals' sexes and SNPs. Using new data from multiple natural populations, we show that a recently proposed candidate for this species' male-determining gene is probably not completely sex-linked, leaving the maleness factor still unidentified. Variants in the chromosome 12 region carrying the candidate gene sometimes show linkage disequilibrium with the sex-determining factor, but no consistently male-specific variant has yet been found. Our genetic mapping with molecular markers spread across chromosome 12 confirms that this is the guppy XY pair. We describe two families with recombinants between the X and Y chromosomes, which confirm that the male-determining locus is in the region identified by all previous studies, near the terminal pseudo-autosomal region (PAR), which crosses over at a very high rate in males. We correct the PAR marker order, and assign two unplaced scaffolds to the PAR. We also detect a duplication, with one copy in the male-determining region, explaining signals of sex linkage in a more proximal region.
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Affiliation(s)
- Deborah Charlesworth
- Institute of Evolutionary Biology, School of Biological Sciences, University of Edinburgh, West Mains Road, EH9 3LF, UK
| | - Roberta Bergero
- Institute of Evolutionary Biology, School of Biological Sciences, University of Edinburgh, West Mains Road, EH9 3LF, UK
| | - Chay Graham
- University of Cambridge, Department of Biochemistry, Sanger Building, 80 Tennis Ct Rd, Cambridge CB2 1GA, UK
| | - Jim Gardner
- Institute of Evolutionary Biology, School of Biological Sciences, University of Edinburgh, West Mains Road, EH9 3LF, UK
| | - Lengxob Yong
- Centre for Ecology and Conservation, University of Exeter, Penryn, Falmouth, Cornwall, TR10 9FE, UK
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18
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Degrandi TM, Barcellos SA, Costa AL, Garnero ADV, Hass I, Gunski RJ. Introducing the Bird Chromosome Database: An Overview of Cytogenetic Studies in Birds. Cytogenet Genome Res 2020; 160:199-205. [PMID: 32369809 DOI: 10.1159/000507768] [Citation(s) in RCA: 30] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2019] [Accepted: 03/26/2020] [Indexed: 11/19/2022] Open
Abstract
Bird chromosomes, which have been investigated scientifically for more than a century, present a number of unique features. In general, bird karyotypes have a high diploid number (2n) of typically around 80 chromosomes that are divided into macro- and microchromosomes. In recent decades, FISH studies using whole chromosome painting probes have shown that the macrochromosomes evolved through both inter- and intrachromosomal rearrangements. However, chromosome painting data are available for only a few bird species, which hinders a more systematic approach to the understanding of the evolutionary history of the enigmatic bird karyotype. Thus, we decided to create an innovative database through compilation of the cytogenetic data available for birds, including chromosome numbers and the results of chromosome painting with chicken (Gallus gallus) probes. The data were obtained through an extensive literature review, which focused on cytogenetic studies published up to 2019. In the first version of the "Bird Chromosome Database (BCD)" (https://sites.unipampa.edu.br/birdchromosomedatabase) we have compiled data on the chromosome numbers of 1,067 bird species and chromosome painting data on 96 species. We found considerable variation in the diploid numbers, which ranged from 40 to 142, although most (around 50%) of the species studied up to now have between 78 and 82 chromosomes. Despite its importance for cytogenetic research, chromosome painting has been applied to less than 1% of all bird species. The BCD will enable researchers to identify the main knowledge gaps in bird cytogenetics, including the most under-sampled groups, and make inferences on chromosomal homologies in phylogenetic studies.
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19
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Kuhl H, Li L, Wuertz S, Stöck M, Liang XF, Klopp C. CSA: A high-throughput chromosome-scale assembly pipeline for vertebrate genomes. Gigascience 2020; 9:giaa034. [PMID: 32449778 PMCID: PMC7247394 DOI: 10.1093/gigascience/giaa034] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2019] [Revised: 01/29/2020] [Accepted: 03/24/2020] [Indexed: 01/14/2023] Open
Abstract
BACKGROUND Easy-to-use and fast bioinformatics pipelines for long-read assembly that go beyond the contig level to generate highly continuous chromosome-scale genomes from raw data remain scarce. RESULT Chromosome-Scale Assembler (CSA) is a novel computationally highly efficient bioinformatics pipeline that fills this gap. CSA integrates information from scaffolded assemblies (e.g., Hi-C or 10X Genomics) or even from diverged reference genomes into the assembly process. As CSA performs automated assembly of chromosome-sized scaffolds, we benchmark its performance against state-of-the-art reference genomes, i.e., conventionally built in a laborious fashion using multiple separate assembly tools and manual curation. CSA increases the contig lengths using scaffolding, local re-assembly, and gap closing. On certain datasets, initial contig N50 may be increased up to 4.5-fold. For smaller vertebrate genomes, chromosome-scale assemblies can be achieved within 12 h using low-cost, high-end desktop computers. Mammalian genomes can be processed within 16 h on compute-servers. Using diverged reference genomes for fish, birds, and mammals, we demonstrate that CSA calculates chromosome-scale assemblies from long-read data and genome comparisons alone. Even contig-level draft assemblies of diverged genomes are helpful for reconstructing chromosome-scale sequences. CSA is also capable of assembling ultra-long reads. CONCLUSIONS CSA can speed up and simplify chromosome-level assembly and significantly lower costs of large-scale family-level vertebrate genome projects.
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Affiliation(s)
- Heiner Kuhl
- Department of Ecophysiology and Aquaculture, Leibniz-Institute of Freshwater Ecology and Inland Fisheries (IGB), Müggelseedamm 310, 12587 Berlin, Germany
| | - Ling Li
- Department of Ecophysiology and Aquaculture, Leibniz-Institute of Freshwater Ecology and Inland Fisheries (IGB), Müggelseedamm 310, 12587 Berlin, Germany
- College of Fisheries, Chinese Perch Research Center, Huazhong Agricultural University; Innovation Base for Chinese Perch Breeding, Key Lab of Freshwater Animal Breeding, Ministry of Agriculture, No.1 Shizishan Street, Hongshan District, 430070 Wuhan, Hubei Province, P.R. China
| | - Sven Wuertz
- Department of Ecophysiology and Aquaculture, Leibniz-Institute of Freshwater Ecology and Inland Fisheries (IGB), Müggelseedamm 310, 12587 Berlin, Germany
| | - Matthias Stöck
- Department of Ecophysiology and Aquaculture, Leibniz-Institute of Freshwater Ecology and Inland Fisheries (IGB), Müggelseedamm 310, 12587 Berlin, Germany
| | - Xu-Fang Liang
- College of Fisheries, Chinese Perch Research Center, Huazhong Agricultural University; Innovation Base for Chinese Perch Breeding, Key Lab of Freshwater Animal Breeding, Ministry of Agriculture, No.1 Shizishan Street, Hongshan District, 430070 Wuhan, Hubei Province, P.R. China
| | - Christophe Klopp
- Sigenae, Bioinfo Genotoul, Mathématiques et Informatique Appliquées de Toulouse, INRAe, 24 Chemin de Borde Rouge, 31320 Auzeville-Tolosane, Castanet Tolosan, France
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20
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Xu L, Wa Sin SY, Grayson P, Edwards SV, Sackton TB. Evolutionary Dynamics of Sex Chromosomes of Paleognathous Birds. Genome Biol Evol 2020; 11:2376-2390. [PMID: 31329234 PMCID: PMC6735826 DOI: 10.1093/gbe/evz154] [Citation(s) in RCA: 36] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/10/2019] [Indexed: 12/20/2022] Open
Abstract
Standard models of sex chromosome evolution propose that recombination suppression leads to the degeneration of the heterogametic chromosome, as is seen for the Y chromosome in mammals and the W chromosome in most birds. Unlike other birds, paleognaths (ratites and tinamous) possess large nondegenerate regions on their sex chromosomes (PARs or pseudoautosomal regions). It remains unclear why these large PARs are retained over >100 Myr, and how this retention impacts the evolution of sex chromosomes within this system. To address this puzzle, we analyzed Z chromosome evolution and gene expression across 12 paleognaths, several of whose genomes have recently been sequenced. We confirm at the genomic level that most paleognaths retain large PARs. As in other birds, we find that all paleognaths have incomplete dosage compensation on the regions of the Z chromosome homologous to degenerated portions of the W (differentiated regions), but we find no evidence for enrichments of male-biased genes in PARs. We find limited evidence for increased evolutionary rates (faster-Z) either across the chromosome or in differentiated regions for most paleognaths with large PARs, but do recover signals of faster-Z evolution in tinamou species with mostly degenerated W chromosomes, similar to the pattern seen in neognaths. Unexpectedly, in some species, PAR-linked genes evolve faster on average than genes on autosomes, suggested by diverse genomic features to be due to reduced efficacy of selection in paleognath PARs. Our analysis shows that paleognath Z chromosomes are atypical at the genomic level, but the evolutionary forces maintaining largely homomorphic sex chromosomes in these species remain elusive.
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Affiliation(s)
- Luohao Xu
- Department of Molecular Evolution and Development, University of Vienna, Austria
| | - Simon Yung Wa Sin
- Department of Organismic and Evolutionary Biology, Harvard University
- Museum of Comparative Zoology, Harvard University
- School of Biological Sciences, The University of Hong Kong, Hong Kong
| | - Phil Grayson
- Department of Organismic and Evolutionary Biology, Harvard University
- Museum of Comparative Zoology, Harvard University
| | - Scott V Edwards
- Department of Organismic and Evolutionary Biology, Harvard University
- Museum of Comparative Zoology, Harvard University
| | - Timothy B Sackton
- Informatics Group, Division of Science, Harvard University
- Corresponding author: E-mail:
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21
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Sun D, Maney DL, Layman TS, Chatterjee P, Yi SV. Regional epigenetic differentiation of the Z Chromosome between sexes in a female heterogametic system. Genome Res 2019; 29:1673-1684. [PMID: 31548356 PMCID: PMC6771406 DOI: 10.1101/gr.248641.119] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2019] [Accepted: 08/07/2019] [Indexed: 01/26/2023]
Abstract
In male heterogametic systems, the X Chromosome is epigenetically differentiated between males and females, to facilitate dosage compensation. For example, the X Chromosome in female mammals is largely inactivated. Relative to well-studied male heterogametic systems, the extent of epigenetic differentiation between male and female Z Chromosomes in female heterogametic species, which often lack complete dosage compensation, is poorly understood. Here, we examined the chromosomal DNA methylation landscapes of male and female Z Chromosomes in two distantly related avian species, namely chicken and white-throated sparrow. We show that, in contrast to the pattern in mammals, male and female Z Chromosomes in these species exhibit highly similar patterns of DNA methylation, which is consistent with weak or absent dosage compensation. We further demonstrate that the epigenetic differences between male and female chicken Z Chromosomes are localized to a few regions, including a previously identified male hypermethylated region 1 (MHM1; CGNC: 80601). We discovered a novel region with elevated male-to-female methylation ratios on the chicken Z Chromosome (male hypermethylated region 2 [MHM2]; CGNC: 80602). The MHM1 and MHM2, despite little sequence similarity between them, bear similar molecular features that are likely associated with their functions. We present evidence consistent with female hypomethylation of MHMs and up-regulation of nearby genes. Therefore, despite little methylation differentiation between sexes, extremely localized DNA methylation differences between male and female chicken Z Chromosomes have evolved and affect expression of nearby regions. Our findings offer new insights into epigenetic regulation of gene expression between sexes in female heterogametic systems.
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Affiliation(s)
- Dan Sun
- School of Biological Sciences, Institute for Bioengineering and Bioscience, Georgia Institute of Technology, Atlanta, Georgia 30332, USA
| | - Donna L Maney
- Department of Psychology, Emory University, Atlanta, Georgia 30322, USA
| | - Thomas S Layman
- School of Biological Sciences, Institute for Bioengineering and Bioscience, Georgia Institute of Technology, Atlanta, Georgia 30332, USA
| | - Paramita Chatterjee
- School of Biological Sciences, Institute for Bioengineering and Bioscience, Georgia Institute of Technology, Atlanta, Georgia 30332, USA
| | - Soojin V Yi
- School of Biological Sciences, Institute for Bioengineering and Bioscience, Georgia Institute of Technology, Atlanta, Georgia 30332, USA
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22
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Comparative Phylogenomics, a Stepping Stone for Bird Biodiversity Studies. DIVERSITY-BASEL 2019. [DOI: 10.3390/d11070115] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
Birds are a group with immense availability of genomic resources, and hundreds of forthcoming genomes at the doorstep. We review recent developments in whole genome sequencing, phylogenomics, and comparative genomics of birds. Short read based genome assemblies are common, largely due to efforts of the Bird 10K genome project (B10K). Chromosome-level assemblies are expected to increase due to improved long-read sequencing. The available genomic data has enabled the reconstruction of the bird tree of life with increasing confidence and resolution, but challenges remain in the early splits of Neoaves due to their explosive diversification after the Cretaceous-Paleogene (K-Pg) event. Continued genomic sampling of the bird tree of life will not just better reflect their evolutionary history but also shine new light onto the organization of phylogenetic signal and conflict across the genome. The comparatively simple architecture of avian genomes makes them a powerful system to study the molecular foundation of bird specific traits. Birds are on the verge of becoming an extremely resourceful system to study biodiversity from the nucleotide up.
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23
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Dynamic evolutionary history and gene content of sex chromosomes across diverse songbirds. Nat Ecol Evol 2019; 3:834-844. [DOI: 10.1038/s41559-019-0850-1] [Citation(s) in RCA: 55] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2018] [Accepted: 02/22/2019] [Indexed: 11/09/2022]
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24
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Yazdi HP, Ellegren H. A Genetic Map of Ostrich Z Chromosome and the Role of Inversions in Avian Sex Chromosome Evolution. Genome Biol Evol 2018; 10:2049-2060. [PMID: 30099482 PMCID: PMC6105114 DOI: 10.1093/gbe/evy163] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/27/2018] [Indexed: 12/11/2022] Open
Abstract
Recombination arrest is a necessary step for the evolution of distinct sex chromosomes. Structural changes, such as inversions, may represent the mechanistic basis for recombination suppression and comparisons of the structural organization of chromosomes as given by chromosome-level assemblies offer the possibility to infer inversions across species at some detail. In birds, deduction of the process of sex chromosome evolution has been hampered by the lack of a validated chromosome-level assembly from a representative of one of the two basal clades of modern birds, Paleognathae. We therefore developed a high-density genetic linkage map of the ostrich Z chromosome and used this to correct an existing assembly, including correction of a large chimeric superscaffold and the order and orientation of other superscaffolds. We identified the pseudoautosomal region as a 52 Mb segment (≈60% of the Z chromosome) where recombination occurred in both sexes. By comparing the order and location of genes on the ostrich Z chromosome with that of six bird species from the other major clade of birds (Neognathae), and of reptilian outgroup species, 25 Z-linked inversions were inferred in the avian lineages. We defined Z chromosome organization in an early avian ancestor and identified inversions spanning the candidate sex-determining DMRT1 gene in this ancestor, which could potentially have triggered the onset of avian sex chromosome evolution. We conclude that avian sex chromosome evolution has been characterized by a complex process of probably both Z-linked and W-linked inversions (and/or other processes). This study illustrates the need for validated chromosome-level assemblies for inference of genome evolution.
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Affiliation(s)
- Homa Papoli Yazdi
- Department of Evolutionary Biology, Evolutionary Biology Centre, Uppsala, Sweden
| | - Hans Ellegren
- Department of Evolutionary Biology, Evolutionary Biology Centre, Uppsala, Sweden
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25
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Charlesworth D. The Guppy Sex Chromosome System and the Sexually Antagonistic Polymorphism Hypothesis for Y Chromosome Recombination Suppression. Genes (Basel) 2018; 9:genes9050264. [PMID: 29783761 PMCID: PMC5977204 DOI: 10.3390/genes9050264] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2018] [Revised: 05/11/2018] [Accepted: 05/16/2018] [Indexed: 02/06/2023] Open
Abstract
Sex chromosomes regularly evolve suppressed recombination, distinguishing them from other chromosomes, and the reason for this has been debated for many years. It is now clear that non-recombining sex-linked regions have arisen in different ways in different organisms. A major hypothesis is that a sex-determining gene arises on a chromosome and that sexually antagonistic (SA) selection (sometimes called intra-locus sexual conflict) acting at a linked gene has led to the evolution of recombination suppression in the region, to reduce the frequency of low fitness recombinant genotypes produced. The sex chromosome system of the guppy (Poecilia reticulata) is often cited as supporting this hypothesis because SA selection has been demonstrated to act on male coloration in natural populations of this fish, and probably contributes to maintaining polymorphisms for the genetic factors involved. I review classical genetic and new molecular genetic results from the guppy, and other fish, including approaches for identifying the genome regions carrying sex-determining loci, and suggest that the guppy may exemplify a recently proposed route to sex chromosome evolution.
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Affiliation(s)
- Deborah Charlesworth
- Institute of Evolutionary Biology, School of Biological Sciences, University of Edinburgh, Edinburgh EH9 3FL, UK.
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26
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Irwin DE. Sex chromosomes and speciation in birds and other ZW systems. Mol Ecol 2018; 27:3831-3851. [PMID: 29443419 DOI: 10.1111/mec.14537] [Citation(s) in RCA: 65] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2017] [Revised: 02/03/2018] [Accepted: 02/06/2018] [Indexed: 01/01/2023]
Abstract
Theory and empirical patterns suggest a disproportionate role for sex chromosomes in evolution and speciation. Focusing on ZW sex determination (females ZW, males ZZ; the system in birds, many snakes, and lepidopterans), I review how evolutionary dynamics are expected to differ between the Z, W and the autosomes, discuss how these differences may lead to a greater role of the sex chromosomes in speciation and use data from birds to compare relative evolutionary rates of sex chromosomes and autosomes. Neutral mutations, partially or completely recessive beneficial mutations, and deleterious mutations under many conditions are expected to accumulate faster on the Z than on autosomes. Sexually antagonistic polymorphisms are expected to arise on the Z, raising the possibility of the spread of preference alleles. The faster accumulation of many types of mutations and the potential for complex evolutionary dynamics of sexually antagonistic traits and preferences contribute to a role for the Z chromosome in speciation. A quantitative comparison among a wide variety of bird species shows that the Z tends to have less within-population diversity and greater between-species differentiation than the autosomes, likely due to both adaptive evolution and a greater rate of fixation of deleterious alleles. The W chromosome also shows strong potential to be involved in speciation, in part because of its co-inheritance with the mitochondrial genome. While theory and empirical evidence suggest a disproportionate role for sex chromosomes in speciation, the importance of sex chromosomes is moderated by their small size compared to the whole genome.
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Affiliation(s)
- Darren E Irwin
- Department of Zoology and Biodiversity Research Centre, University of British Columbia, Vancouver, BC, Canada
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27
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Pucholt P, Wright AE, Conze LL, Mank JE, Berlin S. Recent Sex Chromosome Divergence despite Ancient Dioecy in the Willow Salix viminalis. Mol Biol Evol 2018; 34:1991-2001. [PMID: 28453634 PMCID: PMC5850815 DOI: 10.1093/molbev/msx144] [Citation(s) in RCA: 43] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
Sex chromosomes can evolve when recombination is halted between a pair of chromosomes, and this can lead to degeneration of the sex-limited chromosome. In the early stages of differentiation sex chromosomes are homomorphic, and even though homomorphic sex chromosomes are very common throughout animals and plants, we know little about the evolutionary forces shaping these types of sex chromosomes. We used DNA- and RNA-Seq data from females and males to explore the sex chromosomes in the female heterogametic willow, Salix viminalis, a species with ancient dioecy but with homomorphic sex chromosomes. We detected no major sex differences in read coverage in the sex determination (SD) region, indicating that the W region has not significantly degenerated. However, single nucleotide polymorphism densities in the SD region are higher in females compared with males, indicating very recent recombination suppression, followed by the accumulation of sex-specific single nucleotide polymorphisms. Interestingly, we identified two female-specific scaffolds that likely represent W-chromosome-specific sequence. We show that genes located in the SD region display a mild excess of male-biased expression in sex-specific tissue, and we use allele-specific gene expression analysis to show that this is the result of masculinization of expression on the Z chromosome rather than degeneration of female-expression on the W chromosome. Together, our results demonstrate that insertion of small DNA fragments and accumulation of sex-biased gene expression can occur before the detectable decay of the sex-limited chromosome.
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Affiliation(s)
- Pascal Pucholt
- Department of Plant Biology, Uppsala BioCenter, Linnean Centre for Plant Biology, Swedish University of Agricultural Sciences, Uppsala, Sweden
| | - Alison E Wright
- Department of Genetics, Evolution and Environment, University College London, London, United Kingdom.,Department of Animal and Plant Sciences, University of Sheffield, Sheffield, United Kingdom
| | - Lei Liu Conze
- Department of Plant Biology, Uppsala BioCenter, Linnean Centre for Plant Biology, Swedish University of Agricultural Sciences, Uppsala, Sweden
| | - Judith E Mank
- Department of Genetics, Evolution and Environment, University College London, London, United Kingdom
| | - Sofia Berlin
- Department of Plant Biology, Uppsala BioCenter, Linnean Centre for Plant Biology, Swedish University of Agricultural Sciences, Uppsala, Sweden
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28
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Ishishita S, Matsuda Y. Interspecific hybrids of dwarf hamsters and Phasianidae birds as animal models for studying the genetic and developmental basis of hybrid incompatibility. Genes Genet Syst 2016; 91:63-75. [PMID: 27628130 DOI: 10.1266/ggs.16-00022] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Abstract
Hybrid incompatibility is important in speciation as it prevents gene flow between closely related populations. Reduced fitness from hybrid incompatibility may also reinforce prezygotic reproductive isolation between sympatric populations. However, the genetic and developmental basis of hybrid incompatibility in higher vertebrates remains poorly understood. Mammals and birds, both amniotes, have similar developmental processes, but marked differences in development such as the XY/ZW sex determination systems and the presence or absence of genomic imprinting. Here, we review the sterile phenotype of hybrids between the Phodopus dwarf hamsters P. campbelli and P. sungorus, and the inviable phenotype of hybrids between two birds of the family Phasianidae, chicken (Gallus gallus domesticus) and Japanese quail (Coturnix japonica). We propose hypotheses for developmental defects that are associated with these hybrid incompatibilities. In addition, we discuss the genetic and developmental basis for these defects in conjunction with recent findings from mouse and avian models of genetics, reproductive biology and genomics. We suggest that these hybrids are ideal animal models for studying the genetic and developmental basis of hybrid incompatibility in amniotes.
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Affiliation(s)
- Satoshi Ishishita
- Avian Bioscience Research Center, Graduate School of Bioagricultural Sciences, Nagoya University
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29
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Wright AE, Harrison PW, Zimmer F, Montgomery SH, Pointer MA, Mank JE. Variation in promiscuity and sexual selection drives avian rate of Faster-Z evolution. Mol Ecol 2016; 24:1218-35. [PMID: 25689782 PMCID: PMC4737241 DOI: 10.1111/mec.13113] [Citation(s) in RCA: 65] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2014] [Revised: 02/10/2015] [Accepted: 02/11/2015] [Indexed: 02/02/2023]
Abstract
Higher rates of coding sequence evolution have been observed on the Z chromosome relative to the autosomes across a wide range of species. However, despite a considerable body of theory, we lack empirical evidence explaining variation in the strength of the Faster-Z Effect. To assess the magnitude and drivers of Faster-Z Evolution, we assembled six de novo transcriptomes, spanning 90 million years of avian evolution. Our analysis combines expression, sequence and polymorphism data with measures of sperm competition and promiscuity. In doing so, we present the first empirical evidence demonstrating the positive relationship between Faster-Z Effect and measures of promiscuity, and therefore variance in male mating success. Our results from multiple lines of evidence indicate that selection is less effective on the Z chromosome, particularly in promiscuous species, and that Faster-Z Evolution in birds is due primarily to genetic drift. Our results reveal the power of mating system and sexual selection in shaping broad patterns in genome evolution.
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Affiliation(s)
- Alison E Wright
- Department of Zoology, Edward Grey Institute, University of Oxford, Oxford, OX1 3PS, UK; Department of Genetics, Evolution and Environment, University College London, London, WC1E 6BT, UK
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30
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Lavretsky P, Peters JL, Winker K, Bahn V, Kulikova I, Zhuravlev YN, Wilson RE, Barger C, Gurney K, McCracken KG. Becoming pure: identifying generational classes of admixed individuals within lesser and greater scaup populations. Mol Ecol 2016; 25:661-74. [DOI: 10.1111/mec.13487] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2015] [Revised: 11/13/2015] [Accepted: 11/17/2015] [Indexed: 12/20/2022]
Affiliation(s)
- Philip Lavretsky
- Department of Biology and Department of Marine Biology and Ecology; Rosenstiel School of Marine and Atmospheric Sciences; University of Miami; Coral Gables FL 33146 USA
| | - Jeffrey L. Peters
- Department of Biological Sciences; Wright State University; 3640 Colonel Glenn Hwy Dayton OH 45435 USA
| | - Kevin Winker
- Institute of Arctic Biology and University of Alaska Museum; University of Alaska Fairbanks; Fairbanks AK 99775 USA
| | - Volker Bahn
- Department of Biological Sciences; Wright State University; 3640 Colonel Glenn Hwy Dayton OH 45435 USA
| | - Irina Kulikova
- Institute of Biology and Soil Science FEB RAS; 159 Stoletiya Ave 690022 Vladivostok Russia
| | - Yuri N. Zhuravlev
- Institute of Biology and Soil Science FEB RAS; 159 Stoletiya Ave 690022 Vladivostok Russia
| | - Robert E. Wilson
- Institute of Arctic Biology and University of Alaska Museum; University of Alaska Fairbanks; Fairbanks AK 99775 USA
| | - Chris Barger
- Institute of Arctic Biology and University of Alaska Museum; University of Alaska Fairbanks; Fairbanks AK 99775 USA
- Alaska Department of Fish and Game; 1300 College Road Fairbanks AK 99701 USA
| | - Kirsty Gurney
- Department of Biology; University of Saskatchewan; 112 Science Place Saskatoon Saskatchewan Canada S7N 5E2
| | - Kevin G. McCracken
- Department of Biology and Department of Marine Biology and Ecology; Rosenstiel School of Marine and Atmospheric Sciences; University of Miami; Coral Gables FL 33146 USA
- Institute of Arctic Biology and University of Alaska Museum; University of Alaska Fairbanks; Fairbanks AK 99775 USA
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31
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Lavretsky P, Dacosta JM, Hernández-Baños BE, Engilis A, Sorenson MD, Peters JL. Speciation genomics and a role for the Z chromosome in the early stages of divergence between Mexican ducks and mallards. Mol Ecol 2015; 24:5364-78. [DOI: 10.1111/mec.13402] [Citation(s) in RCA: 55] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2015] [Revised: 09/23/2015] [Accepted: 09/24/2015] [Indexed: 02/01/2023]
Affiliation(s)
- Philip Lavretsky
- Department of Biological Sciences; Wright State University; 3640 Colonel Glenn Hwy Dayton OH 45435 USA
| | | | - Blanca E. Hernández-Baños
- Departamento de Biología Evolutiva; Facultad de Ciencias; Universidad Nacional Autónoma de México; México Distrito Federal México
| | - Andrew Engilis
- Museum of Wildlife and Fish Biology; Department of Wildlife, Fish, and Conservation Biology; University of California, Davis; One Shields Avenue Davis CA 95616 USA
- Department of Wildlife, Fish and Conservation Biology; University of California, Davis; One Shields Avenue Davis CA 95616 USA
| | | | - Jeffrey L. Peters
- Department of Biological Sciences; Wright State University; 3640 Colonel Glenn Hwy Dayton OH 45435 USA
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32
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Bolívar P, Mugal CF, Nater A, Ellegren H. Recombination Rate Variation Modulates Gene Sequence Evolution Mainly via GC-Biased Gene Conversion, Not Hill-Robertson Interference, in an Avian System. Mol Biol Evol 2015; 33:216-27. [PMID: 26446902 PMCID: PMC4693978 DOI: 10.1093/molbev/msv214] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
The ratio of nonsynonymous to synonymous substitution rates (ω) is often used to measure the strength of natural selection. However, ω may be influenced by linkage among different targets of selection, that is, Hill–Robertson interference (HRI), which reduces the efficacy of selection. Recombination modulates the extent of HRI but may also affect ω by means of GC-biased gene conversion (gBGC), a process leading to a preferential fixation of G:C (“strong,” S) over A:T (“weak,” W) alleles. As HRI and gBGC can have opposing effects on ω, it is essential to understand their relative impact to make proper inferences of ω. We used a model that separately estimated S-to-S, S-to-W, W-to-S, and W-to-W substitution rates in 8,423 avian genes in the Ficedula flycatcher lineage. We found that the W-to-S substitution rate was positively, and the S-to-W rate negatively, correlated with recombination rate, in accordance with gBGC but not predicted by HRI. The W-to-S rate further showed the strongest impact on both dN and dS. However, since the effects were stronger at 4-fold than at 0-fold degenerated sites, likely because the GC content of these sites is farther away from its equilibrium, ω slightly decreases with increasing recombination rate, which could falsely be interpreted as a consequence of HRI. We corroborated this hypothesis analytically and demonstrate that under particular conditions, ω can decrease with increasing recombination rate. Analyses of the site-frequency spectrum showed that W-to-S mutations were skewed toward high, and S-to-W mutations toward low, frequencies, consistent with a prevalent gBGC-driven fixation bias.
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Affiliation(s)
- Paulina Bolívar
- Department of Evolutionary Biology, Evolutionary Biology Centre, Uppsala University, Uppsala, Sweden
| | - Carina F Mugal
- Department of Evolutionary Biology, Evolutionary Biology Centre, Uppsala University, Uppsala, Sweden
| | - Alexander Nater
- Department of Evolutionary Biology, Evolutionary Biology Centre, Uppsala University, Uppsala, Sweden
| | - Hans Ellegren
- Department of Evolutionary Biology, Evolutionary Biology Centre, Uppsala University, Uppsala, Sweden
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33
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Dean R, Harrison PW, Wright AE, Zimmer F, Mank JE. Positive Selection Underlies Faster-Z Evolution of Gene Expression in Birds. Mol Biol Evol 2015; 32:2646-56. [PMID: 26067773 PMCID: PMC4576705 DOI: 10.1093/molbev/msv138] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
The elevated rate of evolution for genes on sex chromosomes compared with autosomes (Fast-X or Fast-Z evolution) can result either from positive selection in the heterogametic sex or from nonadaptive consequences of reduced relative effective population size. Recent work in birds suggests that Fast-Z of coding sequence is primarily due to relaxed purifying selection resulting from reduced relative effective population size. However, gene sequence and gene expression are often subject to distinct evolutionary pressures; therefore, we tested for Fast-Z in gene expression using next-generation RNA-sequencing data from multiple avian species. Similar to studies of Fast-Z in coding sequence, we recover clear signatures of Fast-Z in gene expression; however, in contrast to coding sequence, our data indicate that Fast-Z in expression is due to positive selection acting primarily in females. In the soma, where gene expression is highly correlated between the sexes, we detected Fast-Z in both sexes, although at a higher rate in females, suggesting that many positively selected expression changes in females are also expressed in males. In the gonad, where intersexual correlations in expression are much lower, we detected Fast-Z for female gene expression, but crucially, not males. This suggests that a large amount of expression variation is sex-specific in its effects within the gonad. Taken together, our results indicate that Fast-Z evolution of gene expression is the product of positive selection acting on recessive beneficial alleles in the heterogametic sex. More broadly, our analysis suggests that the adaptive potential of Z chromosome gene expression may be much greater than that of gene sequence, results which have important implications for the role of sex chromosomes in speciation and sexual selection.
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Affiliation(s)
- Rebecca Dean
- Department of Genetics, Evolution and Environment, University College London, London, United Kingdom
| | - Peter W Harrison
- Department of Genetics, Evolution and Environment, University College London, London, United Kingdom
| | - Alison E Wright
- Department of Genetics, Evolution and Environment, University College London, London, United Kingdom
| | - Fabian Zimmer
- Department of Genetics, Evolution and Environment, University College London, London, United Kingdom
| | - Judith E Mank
- Department of Genetics, Evolution and Environment, University College London, London, United Kingdom
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34
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Huang H, Rabosky DL. Sex-linked genomic variation and its relationship to avian plumage dichromatism and sexual selection. BMC Evol Biol 2015; 15:199. [PMID: 26377432 PMCID: PMC4574164 DOI: 10.1186/s12862-015-0480-4] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2015] [Accepted: 09/08/2015] [Indexed: 12/17/2022] Open
Abstract
BACKGROUND Sexual dichromatism is the tendency for sexes to differ in color pattern and represents a striking form of within-species morphological variation. Conspicuous intersexual differences in avian plumage are generally thought to result from Darwinian sexual selection, to the extent that dichromatism is often treated as a surrogate for the intensity of sexual selection in phylogenetic comparative studies. Intense sexual selection is predicted to leave a footprint on genetic evolution by reducing the relative genetic diversity on sex chromosome to that on the autosomes. RESULTS In this study, we test the association between plumage dichromatism and sex-linked genetic diversity using eight species pairs with contrasting levels of dichromatism. We estimated Z-linked and autosomal genetic diversity for these non-model avian species using restriction-site associated (RAD) loci that covered ~3 % of the genome. We find that monochromatic birds consistently have reduced sex-linked genomic variation relative to phylogenetically-paired dichromatic species and this pattern is robust to mutational biases. CONCLUSIONS Our results are consistent with several interpretations. If present-day sexual selection is stronger in dichromatic birds, our results suggest that its impact on sex-linked genomic variation is offset by other processes that lead to proportionately lower Z-linked variation in monochromatic species. We discuss possible factors that may contribute to this discrepancy between phenotypes and genomic variation. Conversely, it is possible that present-day sexual selection -- as measured by the variance in male reproductive success -- is stronger in the set of monochromatic taxa we have examined, potentially reflecting the importance of song, behavior and other non-plumage associated traits as targets of sexual selection. This counterintuitive finding suggests that the relationship between genomic variation and sexual selection is complex and highlights the need for a more comprehensive survey of genomic variation in avian taxa that vary markedly in social and genetic mating systems.
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Affiliation(s)
- Huateng Huang
- Department of Ecology and Evolutionary Biology and Museum of Zoology, University of Michigan, Ann Arbor, MI, 48109, USA.
| | - Daniel L Rabosky
- Department of Ecology and Evolutionary Biology and Museum of Zoology, University of Michigan, Ann Arbor, MI, 48109, USA.
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35
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Conservation of Regional Variation in Sex-Specific Sex Chromosome Regulation. Genetics 2015; 201:587-98. [PMID: 26245831 DOI: 10.1534/genetics.115.179234] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2015] [Accepted: 07/27/2015] [Indexed: 11/18/2022] Open
Abstract
Regional variation in sex-specific gene regulation has been observed across sex chromosomes in a range of animals and is often a function of sex chromosome age. The avian Z chromosome exhibits substantial regional variation in sex-specific regulation, where older regions show elevated levels of male-biased expression. Distinct sex-specific regulation also has been observed across the male hypermethylated (MHM) region, which has been suggested to be a region of nascent dosage compensation. Intriguingly, MHM region regulatory features have not been observed in distantly related avian species despite the hypothesis that it is situated within the oldest region of the avian Z chromosome and is therefore orthologous across most birds. This situation contrasts with the conservation of other aspects of regional variation in gene expression observed on the avian sex chromosomes but could be the result of sampling bias. We sampled taxa across the Galloanserae, an avian clade spanning 90 million years, to test whether regional variation in sex-specific gene regulation across the Z chromosome is conserved. We show that the MHM region is conserved across a large portion of the avian phylogeny, together with other sex-specific regulatory features of the avian Z chromosome. Our results from multiple lines of evidence suggest that the sex-specific expression pattern of the MHM region is not consistent with nascent dosage compensation.
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36
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Zhang J, Li C, Zhou Q, Zhang G. Improving the ostrich genome assembly using optical mapping data. Gigascience 2015; 4:24. [PMID: 25969728 PMCID: PMC4427950 DOI: 10.1186/s13742-015-0062-9] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2015] [Accepted: 04/19/2015] [Indexed: 11/10/2022] Open
Abstract
Background The ostrich (Struthio camelus) is the tallest and heaviest living bird. Ostrich meat is considered a healthy red meat, with an annual worldwide production ranging from 12,000 to 15,000 tons. As part of the avian phylogenomics project, we sequenced the ostrich genome for phylogenetic and comparative genomics analyses. The initial Illumina-based assembly of this genome had a scaffold N50 of 3.59 Mb and a total size of 1.23 Gb. Since longer scaffolds are critical for many genomic analyses, particularly for chromosome-level comparative analysis, we generated optical mapping (OM) data to obtain an improved assembly. The OM technique is a non-PCR-based method to generate genome-wide restriction enzyme maps, which improves the quality of de novo genome assembly. Findings In order to generate OM data, we digested the ostrich genome with KpnI, which yielded 1.99 million DNA molecules (>250 kb) and covered the genome at least 500×. The pattern of molecules was subsequently assembled to align with the Illumina-based assembly to achieve sequence extension. This resulted in an OM assembly with a scaffold N50 of 17.71 Mb, which is 5 times as large as that of the initial assembly. The number of scaffolds covering 90% of the genome was reduced from 414 to 75, which means an average of ~3 super-scaffolds for each chromosome. Upon integrating the OM data with previously published FISH (fluorescence in situ hybridization) markers, we recovered the full PAR (pseudoatosomal region) on the ostrich Z chromosome with 4 super-scaffolds, as well as most of the degenerated regions. Conclusions The OM data significantly improved the assembled scaffolds of the ostrich genome and facilitated chromosome evolution studies in birds. Similar strategies can be applied to other genome sequencing projects to obtain better assemblies.
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Affiliation(s)
- Jilin Zhang
- China National GeneBank, BGI-Shenzhen, Shenzhen,, 518083 China
| | - Cai Li
- China National GeneBank, BGI-Shenzhen, Shenzhen,, 518083 China ; Centre for GeoGenetics, Natural History Museum of Denmark, University of Copenhagen, Øster Voldgade 5-7, 1350 Copenhagen, Denmark
| | - Qi Zhou
- Department of Integrative Biology, University of California, Berkeley, USA
| | - Guojie Zhang
- China National GeneBank, BGI-Shenzhen, Shenzhen,, 518083 China ; Department of Biology, Centre for Social Evolution, University of Copenhagen, Universitetsparken 15, 2100 Copenhagen, DK Denmark
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