1
|
Evans BJ, Mudd AB, Bredeson JV, Furman BLS, Wasonga DV, Lyons JB, Harland RM, Rokhsar DS. New insights into Xenopus sex chromosome genomics from the Marsabit clawed frog X. borealis. J Evol Biol 2022; 35:1777-1790. [PMID: 36054077 PMCID: PMC9722552 DOI: 10.1111/jeb.14078] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2022] [Revised: 06/23/2022] [Accepted: 07/14/2022] [Indexed: 11/26/2022]
Abstract
In many groups, sex chromosomes change frequently but the drivers of their rapid evolution are varied and often poorly characterized. With an aim of further understanding sex chromosome turnover, we investigated the polymorphic sex chromosomes of the Marsabit clawed frog, Xenopus borealis, using genomic data and a new chromosome-scale genome assembly. We confirmed previous findings that 54.1 Mb of chromosome 8L is sex-linked in animals from east Kenya and a laboratory strain, but most (or all) of this region is not sex-linked in natural populations from west Kenya. Previous work suggests possible degeneration of the Z chromosomes in the east population because many sex-linked transcripts of this female heterogametic population have female-biased expression, and we therefore expected this chromosome to not be present in the west population. In contrast, our simulations support a model where most or all of the sex-linked portion of the Z chromosome from the east acquired autosomal segregation in the west, and where much genetic variation specific to the large sex-linked portion of the W chromosome from the east is not present in the west. These recent changes are consistent with the hot-potato model, wherein sex chromosome turnover is favoured by natural selection if it purges a (minimally) degenerate sex-specific sex chromosome, but counterintuitively suggest natural selection failed to purge a Z chromosome that has signs of more advanced and possibly more ancient regulatory degeneration. These findings highlight complex evolutionary dynamics of young, rapidly evolving Xenopus sex chromosomes and set the stage for mechanistic work aimed at pinpointing additional sex-determining genes in this group.
Collapse
Affiliation(s)
- Ben J Evans
- Biology Department, Life Sciences Building Room 328, McMaster University, Hamilton, Ontario, Canada
| | - Austin B Mudd
- Department of Molecular and Cell Biology, University of California, Berkeley, California, USA
| | - Jessen V Bredeson
- Department of Molecular and Cell Biology, University of California, Berkeley, California, USA
| | - Benjamin L S Furman
- Biology Department, Life Sciences Building Room 328, McMaster University, Hamilton, Ontario, Canada
- Canexia Health, Vancouver, British Columbia, Canada
| | | | - Jessica B Lyons
- Department of Molecular and Cell Biology, University of California, Berkeley, California, USA
| | - Richard M Harland
- Department of Molecular and Cell Biology, University of California, Berkeley, California, USA
| | - Dan S Rokhsar
- Department of Molecular and Cell Biology, University of California, Berkeley, California, USA
- Okinawa Institute of Science and Technology Graduate University, Onna, Japan
- Chan-Zuckerberg BioHub, San Francisco, California, USA
| |
Collapse
|
2
|
Lin Y, Darolti I, Furman BLS, Almeida P, Sandkam BA, Breden F, Wright AE, Mank JE. Gene duplication to the Y chromosome in Trinidadian Guppies. Mol Ecol 2022; 31:1853-1863. [PMID: 35060220 DOI: 10.1111/mec.16355] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2021] [Revised: 12/06/2021] [Accepted: 01/07/2022] [Indexed: 11/29/2022]
Abstract
Differences in allele frequencies at autosomal genes between males and females in a population can result from two scenarios. First, unresolved sexual conflict over survival can produce allelic differentiation between the sexes. However, given the substantial mortality costs required to produce allelic differences between males and females at each generation, it remains unclear how many loci within the genome experience significant sexual conflict over survival. Alternatively, recent studies have shown that similarity between autosomal and Y sequences can create perceived allelic differences between the sexes. However, Y duplications are most likely in species with large non-recombining regions, in part because they simply represent larger targets for duplications. We assessed the genomes of 120 wild-caught guppies, which experience extensive predation- and pathogen-induced mortality and have a relatively small ancestral Y chromosome. We identified seven autosomal genes that show allelic differences between male and female adults. Five of these genes show clear evidence of whole or partial gene duplication between the Y chromosome and the autosomes. The remaining two genes show evidence of partial homology to the Y. Overall, our findings suggest that the guppy genome experiences a very low level of unresolved sexual conflict over survival, and instead the Y chromosome, despite its small ancestral size and recent origin, may nonetheless accumulate genes with male-specific functions.
Collapse
Affiliation(s)
- Yuying Lin
- Department of Zoology and Biodiversity Research Centre, University of British Columbia, Canada
| | - Iulia Darolti
- Department of Zoology and Biodiversity Research Centre, University of British Columbia, Canada
| | - Benjamin L S Furman
- Department of Zoology and Biodiversity Research Centre, University of British Columbia, Canada
| | - Pedro Almeida
- Department of Genetics, Evolution and Environment, University College London, United Kingdom
| | - Benjamin A Sandkam
- Department of Zoology and Biodiversity Research Centre, University of British Columbia, Canada
| | - Felix Breden
- Department of Biological Sciences, Simon Fraser University, Canada
| | - Alison E Wright
- Ecology and Evolutionary Biology, School of Biosciences, University of Sheffield
| | - Judith E Mank
- Department of Zoology and Biodiversity Research Centre, University of British Columbia, Canada.,Biosciences, University of Exeter, Penryn Campus, United Kingdom
| |
Collapse
|
3
|
Song XY, Furman BLS, Premachandra T, Knytl M, Cauret CMS, Wasonga DV, Measey J, Dworkin I, Evans BJ. Sex chromosome degeneration, turnover, and sex-biased expression of sex-linked transcripts in African clawed frogs ( Xenopus). Philos Trans R Soc Lond B Biol Sci 2021; 376:20200095. [PMID: 34247503 DOI: 10.1098/rstb.2020.0095] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023] Open
Abstract
The tempo of sex chromosome evolution-how quickly, in what order, why and how their particular characteristics emerge during evolution-remains poorly understood. To understand this further, we studied three closely related species of African clawed frog (genus Xenopus), that each has independently evolved sex chromosomes. We identified population polymorphism in the extent of sex chromosome differentiation in wild-caught Xenopus borealis that corresponds to a large, previously identified region of recombination suppression. This large sex-linked region of X. borealis has an extreme concentration of genes that encode transcripts with sex-biased expression, and we recovered similar findings in the smaller sex-linked regions of Xenopus laevis and Xenopus tropicalis. In two of these species, strong skews in expression (mostly female-biased in X. borealis, mostly male-biased in X. tropicalis) are consistent with expectations associated with recombination suppression, and in X. borealis, we hypothesize that a degenerate ancestral Y-chromosome transitioned into its contemporary Z-chromosome. These findings indicate that Xenopus species are tolerant of differences between the sexes in dosage of the products of multiple genes, and offer insights into how evolutionary transformations of ancestral sex chromosomes carry forward to affect the function of new sex chromosomes. This article is part of the theme issue 'Challenging the paradigm in sex chromosome evolution: empirical and theoretical insights with a focus on vertebrates (Part I)'.
Collapse
Affiliation(s)
- Xue-Ying Song
- Department of Biology, McMaster University, 1280 Main Street West, Hamilton, Ontario, Canada L8S 4K1
| | - Benjamin L S Furman
- Department of Biology, McMaster University, 1280 Main Street West, Hamilton, Ontario, Canada L8S 4K1.,Department of Zoology, University of British Columbia, 6270 University Boulevard, Vancouver, British Columbia, Canada V6T 1Z4
| | - Tharindu Premachandra
- Department of Biology, McMaster University, 1280 Main Street West, Hamilton, Ontario, Canada L8S 4K1
| | - Martin Knytl
- Department of Biology, McMaster University, 1280 Main Street West, Hamilton, Ontario, Canada L8S 4K1.,Department of Cell Biology, Charles University, 7 Vinicna Street, Prague 12843, Czech Republic
| | - Caroline M S Cauret
- Department of Biology, McMaster University, 1280 Main Street West, Hamilton, Ontario, Canada L8S 4K1
| | | | - John Measey
- Centre for Invasion Biology, Department of Botany and Zoology, Stellenbosch University, Private Bag X1, Matieland, 7602 Stellenbosch, South Africa
| | - Ian Dworkin
- Department of Biology, McMaster University, 1280 Main Street West, Hamilton, Ontario, Canada L8S 4K1
| | - Ben J Evans
- Department of Biology, McMaster University, 1280 Main Street West, Hamilton, Ontario, Canada L8S 4K1
| |
Collapse
|
4
|
Furman BLS, Cauret CMS, Knytl M, Song XY, Premachandra T, Ofori-Boateng C, Jordan DC, Horb ME, Evans BJ. A frog with three sex chromosomes that co-mingle together in nature: Xenopus tropicalis has a degenerate W and a Y that evolved from a Z chromosome. PLoS Genet 2020; 16:e1009121. [PMID: 33166278 PMCID: PMC7652241 DOI: 10.1371/journal.pgen.1009121] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2020] [Accepted: 09/16/2020] [Indexed: 11/18/2022] Open
Abstract
In many species, sexual differentiation is a vital prelude to reproduction, and disruption of this process can have severe fitness effects, including sterility. It is thus interesting that genetic systems governing sexual differentiation vary among-and even within-species. To understand these systems more, we investigated a rare example of a frog with three sex chromosomes: the Western clawed frog, Xenopus tropicalis. We demonstrate that natural populations from the western and eastern edges of Ghana have a young Y chromosome, and that a male-determining factor on this Y chromosome is in a very similar genomic location as a previously known female-determining factor on the W chromosome. Nucleotide polymorphism of expressed transcripts suggests genetic degeneration on the W chromosome, emergence of a new Y chromosome from an ancestral Z chromosome, and natural co-mingling of the W, Z, and Y chromosomes in the same population. Compared to the rest of the genome, a small sex-associated portion of the sex chromosomes has a 50-fold enrichment of transcripts with male-biased expression during early gonadal differentiation. Additionally, X. tropicalis has sex-differences in the rates and genomic locations of recombination events during gametogenesis that are similar to at least two other Xenopus species, which suggests that sex differences in recombination are genus-wide. These findings are consistent with theoretical expectations associated with recombination suppression on sex chromosomes, demonstrate that several characteristics of old and established sex chromosomes (e.g., nucleotide divergence, sex biased expression) can arise well before sex chromosomes become cytogenetically distinguished, and show how these characteristics can have lingering consequences that are carried forward through sex chromosome turnovers.
Collapse
Affiliation(s)
- Benjamin L. S. Furman
- Department of Biology, McMaster University, 1280 Main Street West, Hamilton, Ontario, L8S 4K1, Canada
- Department of Zoology, University of British Columbia, 6270 University Blvd Vancouver, British Columbia, V6T 1Z4 Canada
| | - Caroline M. S. Cauret
- Department of Biology, McMaster University, 1280 Main Street West, Hamilton, Ontario, L8S 4K1, Canada
| | - Martin Knytl
- Department of Biology, McMaster University, 1280 Main Street West, Hamilton, Ontario, L8S 4K1, Canada
- Department of Cell Biology, Charles University, 7 Vinicna Street, Prague, 12843, Czech Republic
| | - Xue-Ying Song
- Department of Biology, McMaster University, 1280 Main Street West, Hamilton, Ontario, L8S 4K1, Canada
| | - Tharindu Premachandra
- Department of Biology, McMaster University, 1280 Main Street West, Hamilton, Ontario, L8S 4K1, Canada
| | | | - Danielle C. Jordan
- Eugene Bell Center for Regenerative Biology and Tissue Engineering and National Xenopus Resource, Marine Biological Laboratory, 7 MBL St, Woods Hole, MA 02543 USA
| | - Marko E. Horb
- Eugene Bell Center for Regenerative Biology and Tissue Engineering and National Xenopus Resource, Marine Biological Laboratory, 7 MBL St, Woods Hole, MA 02543 USA
| | - Ben J. Evans
- Department of Biology, McMaster University, 1280 Main Street West, Hamilton, Ontario, L8S 4K1, Canada
| |
Collapse
|
5
|
Cauret CMS, Gansauge MT, Tupper AS, Furman BLS, Knytl M, Song X, Greenbaum E, Meyer M, Evans BJ. Erratum to: Developmental systems drift and the drivers of sex chromosome evolution. Mol Biol Evol 2020; 37:1844. [DOI: 10.1093/molbev/msz286] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
|
6
|
Furman BLS, Metzger DCH, Darolti I, Wright AE, Sandkam BA, Almeida P, Shu JJ, Mank JE. Sex Chromosome Evolution: So Many Exceptions to the Rules. Genome Biol Evol 2020; 12:750-763. [PMID: 32315410 PMCID: PMC7268786 DOI: 10.1093/gbe/evaa081] [Citation(s) in RCA: 98] [Impact Index Per Article: 24.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 04/14/2020] [Indexed: 01/10/2023] Open
Abstract
Genomic analysis of many nonmodel species has uncovered an incredible diversity of sex chromosome systems, making it possible to empirically test the rich body of evolutionary theory that describes each stage of sex chromosome evolution. Classic theory predicts that sex chromosomes originate from a pair of homologous autosomes and recombination between them is suppressed via inversions to resolve sexual conflict. The resulting degradation of the Y chromosome gene content creates the need for dosage compensation in the heterogametic sex. Sex chromosome theory also implies a linear process, starting from sex chromosome origin and progressing to heteromorphism. Despite many convergent genomic patterns exhibited by independently evolved sex chromosome systems, and many case studies supporting these theoretical predictions, emerging data provide numerous interesting exceptions to these long-standing theories, and suggest that the remarkable diversity of sex chromosomes is matched by a similar diversity in their evolution. For example, it is clear that sex chromosome pairs are not always derived from homologous autosomes. In addition, both the cause and the mechanism of recombination suppression between sex chromosome pairs remain unclear, and it may be that the spread of recombination suppression is a more gradual process than previously thought. It is also clear that dosage compensation can be achieved in many ways, and displays a range of efficacy in different systems. Finally, the remarkable turnover of sex chromosomes in many systems, as well as variation in the rate of sex chromosome divergence, suggest that assumptions about the inevitable linearity of sex chromosome evolution are not always empirically supported, and the drivers of the birth-death cycle of sex chromosome evolution remain to be elucidated. Here, we concentrate on how the diversity in sex chromosomes across taxa highlights an equal diversity in each stage of sex chromosome evolution.
Collapse
Affiliation(s)
- Benjamin L S Furman
- Beaty Biodiversity Research Centre, University of British Columbia, Vancouver, British Columbia, Canada
- Department of Zoology, University of British Columbia, Vancouver, British Columbia, Canada
| | - David C H Metzger
- Beaty Biodiversity Research Centre, University of British Columbia, Vancouver, British Columbia, Canada
- Department of Zoology, University of British Columbia, Vancouver, British Columbia, Canada
| | - Iulia Darolti
- Beaty Biodiversity Research Centre, University of British Columbia, Vancouver, British Columbia, Canada
- Department of Zoology, University of British Columbia, Vancouver, British Columbia, Canada
| | - Alison E Wright
- Department of Animal and Plant Sciences, University of Sheffield, United Kingdom
| | - Benjamin A Sandkam
- Beaty Biodiversity Research Centre, University of British Columbia, Vancouver, British Columbia, Canada
- Department of Zoology, University of British Columbia, Vancouver, British Columbia, Canada
| | - Pedro Almeida
- Department of Genetics, Evolution and Environment, University College London, United Kingdom
| | - Jacelyn J Shu
- Beaty Biodiversity Research Centre, University of British Columbia, Vancouver, British Columbia, Canada
- Department of Zoology, University of British Columbia, Vancouver, British Columbia, Canada
| | - Judith E Mank
- Beaty Biodiversity Research Centre, University of British Columbia, Vancouver, British Columbia, Canada
- Department of Zoology, University of British Columbia, Vancouver, British Columbia, Canada
- Department of Genetics, Evolution and Environment, University College London, United Kingdom
| |
Collapse
|
7
|
Cauret CMS, Gansauge MT, Tupper AS, Furman BLS, Knytl M, Song XY, Greenbaum E, Meyer M, Evans BJ. Developmental Systems Drift and the Drivers of Sex Chromosome Evolution. Mol Biol Evol 2019; 37:799-810. [DOI: 10.1093/molbev/msz268] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023] Open
Abstract
AbstractPhenotypic invariance—the outcome of purifying selection—is a hallmark of biological importance. However, invariant phenotypes might be controlled by diverged genetic systems in different species. Here, we explore how an important and invariant phenotype—the development of sexually differentiated individuals—is controlled in over two dozen species in the frog family Pipidae. We uncovered evidence in different species for 1) an ancestral W chromosome that is not found in many females and is found in some males, 2) independent losses and 3) autosomal segregation of this W chromosome, 4) changes in male versus female heterogamy, and 5) substantial variation among species in recombination suppression on sex chromosomes. We further provide evidence of, and evolutionary context for, the origins of at least seven distinct systems for regulating sex determination among three closely related genera. These systems are distinct in their genomic locations, evolutionary origins, and/or male versus female heterogamy. Our findings demonstrate that the developmental control of sexual differentiation changed via loss, sidelining, and empowerment of a mechanistically influential gene, and offer insights into novel factors that impinge on the diverse evolutionary fates of sex chromosomes.
Collapse
Affiliation(s)
| | - Marie-Theres Gansauge
- Department of Evolutionary Genetics, Max Planck Institute for Evolutionary Anthropology, Leipzig, Germany
| | - Andrew S Tupper
- Origins Institute and Department of Biochemistry and Biomedical Science, McMaster University, Hamilton, Canada
| | - Benjamin L S Furman
- Biology Department, McMaster University, Hamilton, Canada
- Department of Zoology, Biodiversity Research Centre, University of British Columbia, Vancouver, Canada
| | - Martin Knytl
- Biology Department, McMaster University, Hamilton, Canada
- Department of Cell Biology, Charles University, Prague 2, Czech Republic
| | - Xue-Ying Song
- Biology Department, McMaster University, Hamilton, Canada
| | - Eli Greenbaum
- Department of Biological Sciences, The University of Texas at El Paso, El Paso, TX
| | - Matthias Meyer
- Department of Evolutionary Genetics, Max Planck Institute for Evolutionary Anthropology, Leipzig, Germany
| | - Ben J Evans
- Biology Department, McMaster University, Hamilton, Canada
| |
Collapse
|
8
|
Evans BJ, Gansauge MT, Stanley EL, Furman BLS, Cauret CMS, Ofori-Boateng C, Gvoždík V, Streicher JW, Greenbaum E, Tinsley RC, Meyer M, Blackburn DC. Xenopus fraseri: Mr. Fraser, where did your frog come from? PLoS One 2019; 14:e0220892. [PMID: 31509539 PMCID: PMC6738922 DOI: 10.1371/journal.pone.0220892] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2019] [Accepted: 07/23/2019] [Indexed: 01/06/2023] Open
Abstract
A comprehensive, accurate, and revisable alpha taxonomy is crucial for biodiversity studies, but is challenging when data from reference specimens are difficult to collect or observe. However, recent technological advances can overcome some of these challenges. To illustrate this, we used modern approaches to tackle a centuries-old taxonomic enigma presented by Fraser’s Clawed Frog, Xenopus fraseri, including whether X. fraseri is different from other species, and if so, where it is situated geographically and phylogenetically. To facilitate these inferences, we used high-resolution techniques to examine morphological variation, and we generated and analyzed complete mitochondrial genome sequences from all Xenopus species, including >150-year-old type specimens. Our results demonstrate that X. fraseri is indeed distinct from other species, firmly place this species within a phylogenetic context, and identify its minimal geographic distribution in northern Ghana and northern Cameroon. These data also permit novel phylogenetic resolution into this intensively studied and biomedically important group. Xenopus fraseri was formerly thought to be a rainforest endemic placed alongside species in the amieti species group; in fact this species occurs in arid habitat on the borderlands of the Sahel, and is the smallest member of the muelleri species group. This study illustrates that the taxonomic enigma of Fraser’s frog was a combined consequence of sparse collection records, interspecies conservation and intraspecific polymorphism in external anatomy, and type specimens with unusual morphology.
Collapse
Affiliation(s)
- Ben J. Evans
- Department of Biology, McMaster University, Hamilton, ON, Canada
- * E-mail:
| | - Marie-Theres Gansauge
- Max Planck Institute for Evolutionary Anthropology, Deutscher Platz, Leipzig, Germany
| | - Edward L. Stanley
- Florida Museum of Natural History, University of Florida, Gainesville, FL, United States of America
| | - Benjamin L. S. Furman
- Department of Biology, McMaster University, Hamilton, ON, Canada
- Department of Zoology, Beaty Biodiversity Research Centre, University of British Columbia, Vancouver, British Columbia, Canada
| | | | | | - Václav Gvoždík
- Institute of Vertebrate Biology of the Czech Academy of Sciences, Czech Republic
- Department of Zoology, National Museum, Prague, Czech Republic
| | | | - Eli Greenbaum
- Department of Biological Sciences, University of Texas at El Paso, El Paso, United States of America
| | - Richard C. Tinsley
- School of Biological Sciences, University of Bristol, Bristol, United Kingdom
| | - Matthias Meyer
- Max Planck Institute for Evolutionary Anthropology, Deutscher Platz, Leipzig, Germany
| | - David C. Blackburn
- Florida Museum of Natural History, University of Florida, Gainesville, FL, United States of America
| |
Collapse
|
9
|
Furman BLS, Dang UJ, Evans BJ, Golding GB. Divergent subgenome evolution after allopolyploidization in African clawed frogs (Xenopus). J Evol Biol 2018; 31:1945-1958. [DOI: 10.1111/jeb.13391] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2018] [Revised: 09/26/2018] [Accepted: 10/06/2018] [Indexed: 12/22/2022]
Affiliation(s)
| | - Utkarsh J. Dang
- Department of Health Outcomes and Administrative Sciences; School of Pharmacy and Pharmaceutical Sciences; Binghamton University; State University of New York; Binghamton NY USA
| | - Ben J. Evans
- Department of Biology; McMaster University; Hamilton ON Canada
| | | |
Collapse
|
10
|
Furman BLS, Evans BJ. Divergent Evolutionary Trajectories of Two Young, Homomorphic, and Closely Related Sex Chromosome Systems. Genome Biol Evol 2018; 10:742-755. [PMID: 29608717 PMCID: PMC5841384 DOI: 10.1093/gbe/evy045] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 02/20/2018] [Indexed: 02/02/2023] Open
Abstract
There exists extraordinary variation among species in the degree and nature of sex chromosome divergence. However, much of our knowledge about sex chromosomes is based on comparisons between deeply diverged species with different ancestral sex chromosomes, making it difficult to establish how fast and why sex chromosomes acquire variable levels of divergence. To address this problem, we studied sex chromosome evolution in two species of African clawed frog (Xenopus), both of whom acquired novel systems for sex determination from a recent common ancestor, and both of whom have female (ZW/ZZ) heterogamy. Derived sex chromosomes of one species, X. laevis, have a small region of suppressed recombination that surrounds the sex determining locus, and have remained this way for millions of years. In the other species, X. borealis, a younger sex chromosome system exists on a different pair of chromosomes, but the region of suppressed recombination surrounding an unidentified sex determining gene is vast, spanning almost half of the sex chromosomes. Differences between these sex chromosome systems are also apparent in the extent of nucleotide divergence between the sex chromosomes carried by females. Our analyses also indicate that in autosomes of both of these species, recombination during oogenesis occurs more frequently and in different genomic locations than during spermatogenesis. These results demonstrate that new sex chromosomes can assume radically different evolutionary trajectories, with far-reaching genomic consequences. They also suggest that in some instances the origin of new triggers for sex determination may be coupled with rapid evolution sex chromosomes, including recombination suppression of large genomic regions.
Collapse
Affiliation(s)
| | - Ben J Evans
- Department of Biology, McMaster University, Hamilton, Ontario, Canada
| |
Collapse
|
11
|
Furman BLS, Scheffers BR, Taylor M, Davis C, Paszkowski CA. Limited genetic structure in a wood frog (Lithobates sylvaticus) population in an urban landscape inhabiting natural and constructed wetlands. CONSERV GENET 2015. [DOI: 10.1007/s10592-015-0757-6] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
|
12
|
Furman BLS, Bewick AJ, Harrison TL, Greenbaum E, Gvoždík V, Kusamba C, Evans BJ. Pan-African phylogeography of a model organism, the African clawed frog 'Xenopus laevis'. Mol Ecol 2015; 24:909-25. [PMID: 25583226 DOI: 10.1111/mec.13076] [Citation(s) in RCA: 43] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2014] [Revised: 01/06/2015] [Accepted: 01/08/2015] [Indexed: 11/30/2022]
Abstract
The African clawed frog Xenopus laevis has a large native distribution over much of sub-Saharan Africa and is a model organism for research, a proposed disease vector, and an invasive species. Despite its prominent role in research and abundance in nature, surprisingly little is known about the phylogeography and evolutionary history of this group. Here, we report an analysis of molecular variation of this clade based on 17 loci (one mitochondrial, 16 nuclear) in up to 159 individuals sampled throughout its native distribution. Phylogenetic relationships among mitochondrial DNA haplotypes were incongruent with those among alleles of the putatively female-specific sex-determining gene DM-W, in contrast to the expectation of strict matrilineal inheritance of both loci. Population structure and evolutionarily diverged lineages were evidenced by analyses of molecular variation in these data. These results further contextualize the chronology, and evolutionary relationships within this group, support the recognition of X. laevis sensu stricto, X. petersii, X. victorianus and herein revalidated X. poweri as separate species. We also propose that portions of the currently recognized distributions of X. laevis (north of the Congo Basin) and X. petersii (south of the Congo Basin) be reassigned to X. poweri.
Collapse
Affiliation(s)
- Benjamin L S Furman
- Biology Department, McMaster University, Life Sciences Building, 1280 Main Street West, Hamilton, Ontario, Canada, L8S 4K1
| | | | | | | | | | | | | |
Collapse
|