1
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McAllester CS, Pool JE. Inversions Can Accumulate Balanced Sexual Antagonism: Evidence from Simulations and Drosophila Experiments. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2023.10.02.560529. [PMID: 37873205 PMCID: PMC10592935 DOI: 10.1101/2023.10.02.560529] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/25/2023]
Abstract
Chromosomal inversion polymorphisms can be common, but the causes of their persistence are often unclear. We propose a model for the maintenance of inversion polymorphism, which requires that some variants contribute antagonistically to two phenotypes, one of which has negative frequency-dependent fitness. These conditions yield a form of frequency-dependent disruptive selection, favoring two predominant haplotypes segregating alleles that favor opposing antagonistic phenotypes. An inversion associated with one haplotype can reduce the fitness load incurred by generating recombinant offspring, reinforcing its linkage to the haplotype and enabling both haplotypes to accumulate more antagonistic variants than expected otherwise. We develop and apply a forward simulator to examine these dynamics under a tradeoff between survival and male display. These simulations indeed generate inversion-associated haplotypes with opposing sex-specific fitness effects. Antagonism strengthens with time, and can ultimately yield karyotypes at surprisingly predictable frequencies, with striking genotype frequency differences between sexes and between developmental stages. To test whether this model may contribute to well-studied yet enigmatic inversion polymorphisms in Drosophila melanogaster, we track inversion frequencies in laboratory crosses to test whether they influence male reproductive success or survival. We find that two of the four tested inversions show significant evidence for the tradeoff examined, with In(3R)K favoring survival and In(3L)Ok favoring male reproduction. In line with the apparent sex-specific fitness effects implied for both of those inversions, In(3L)Ok was also found to be less costly to the viability and/or longevity of males than females, whereas In(3R)K was more beneficial to female survival. Based on this work, we expect that balancing selection on antagonistically pleiotropic traits may provide a significant and underappreciated contribution to the maintenance of natural inversion polymorphism.
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Affiliation(s)
| | - John E. Pool
- Laboratory of Genetics, University of Wisconsin – Madison, USA
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2
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Kitano J, Ansai S, Takehana Y, Yamamoto Y. Diversity and Convergence of Sex-Determination Mechanisms in Teleost Fish. Annu Rev Anim Biosci 2024; 12:233-259. [PMID: 37863090 DOI: 10.1146/annurev-animal-021122-113935] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2023]
Abstract
Sexual reproduction is prevalent across diverse taxa. However, sex-determination mechanisms are so diverse that even closely related species often differ in sex-determination systems. Teleost fish is a taxonomic group with frequent turnovers of sex-determining mechanisms and thus provides us with great opportunities to investigate the molecular and evolutionary mechanisms underlying the turnover of sex-determining systems. Here, we compile recent studies on the diversity of sex-determination mechanisms in fish. We demonstrate that genes in the TGF-β signaling pathway are frequently used for master sex-determining (MSD) genes. MSD genes arise via two main mechanisms, duplication-and-transposition and allelic mutations, with a few exceptions. We also demonstrate that temperature influences sex determination in many fish species, even those with sex chromosomes, with higher temperatures inducing differentiation into males in most cases. Finally, we review theoretical models for the turnover of sex-determining mechanisms and discuss what questions remain elusive.
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Affiliation(s)
- Jun Kitano
- Ecological Genetics Laboratory, National Institute of Genetics, Mishima, Shizuoka, Japan;
| | - Satoshi Ansai
- Graduate School of Life Sciences, Tohoku University, Sendai, Miyagi, Japan
- Graduate School of Agriculture, Kyoto University, Kyoto, Japan;
| | - Yusuke Takehana
- Faculty of Bio-Science, Nagahama Institute of Bio-Science and Technology, Nagahama, Shiga, Japan;
| | - Yoji Yamamoto
- Department of Marine Biosciences, Tokyo University of Marine Science and Technology, Tokyo, Japan;
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3
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Hu N, Sanderson BJ, Guo M, Feng G, Gambhir D, Hale H, Wang D, Hyden B, Liu J, Smart LB, DiFazio SP, Ma T, Olson MS. Evolution of a ZW sex chromosome system in willows. Nat Commun 2023; 14:7144. [PMID: 37932261 PMCID: PMC10628195 DOI: 10.1038/s41467-023-42880-5] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2022] [Accepted: 10/24/2023] [Indexed: 11/08/2023] Open
Abstract
Transitions in the heterogamety of sex chromosomes (e.g., XY to ZW or vice versa) fundamentally alter the genetic basis of sex determination, however the details of these changes have been studied in only a few cases. In an XY to ZW transition, the X is likely to give rise to the W because they both carry feminizing genes and the X is expected to harbour less genetic load than the Y. Here, using a new reference genome for Salix exigua, we trace the X, Y, Z, and W sex determination regions during the homologous transition from an XY system to a ZW system in willow (Salix). We show that both the W and the Z arose from the Y chromosome. We find that the new Z chromosome shares multiple homologous putative masculinizing factors with the ancestral Y, whereas the new W lost these masculinizing factors and gained feminizing factors. The origination of both the W and Z from the Y was permitted by an unexpectedly low genetic load on the Y and this indicates that the origins of sex chromosomes during homologous transitions may be more flexible than previously considered.
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Affiliation(s)
- Nan Hu
- Department of Biological Sciences, Texas Tech University, Lubbock, TX, USA
| | - Brian J Sanderson
- Department of Molecular Biosciences, University of Kansas, Lawrence, KS, USA
| | - Minghao Guo
- Department of Biological Sciences, Texas Tech University, Lubbock, TX, USA
| | - Guanqiao Feng
- Department of Biological Sciences, Texas Tech University, Lubbock, TX, USA
| | - Diksha Gambhir
- Department of Biological Sciences, Texas Tech University, Lubbock, TX, USA
| | - Haley Hale
- HudsonAlpha Institute for Biotechnology, 601 Genome Way, Huntsville, AL, USA
| | - Deyan Wang
- Key Laboratory of Bio-Resource and Eco-Environment of Ministry of Education, College of Life Sciences, Sichuan University, Chengdu, China
| | - Brennan Hyden
- Horticulture Section, School of Integrative Plant Science, Cornell University, Cornell AgriTech, Geneva, NY, USA
| | - Jianquan Liu
- Key Laboratory of Bio-Resource and Eco-Environment of Ministry of Education, College of Life Sciences, Sichuan University, Chengdu, China
| | - Lawrence B Smart
- Horticulture Section, School of Integrative Plant Science, Cornell University, Cornell AgriTech, Geneva, NY, USA
| | - Stephen P DiFazio
- Department of Biology, West Virginia University, Morgantown, WV, USA
| | - Tao Ma
- Key Laboratory of Bio-Resource and Eco-Environment of Ministry of Education, College of Life Sciences, Sichuan University, Chengdu, China
| | - Matthew S Olson
- Department of Biological Sciences, Texas Tech University, Lubbock, TX, USA.
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4
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Kitano J, Ansai S, Fujimoto S, Kakioka R, Sato M, Mandagi IF, Sumarto BKA, Yamahira K. A Cryptic Sex-Linked Locus Revealed by the Elimination of a Master Sex-Determining Locus in Medaka Fish. Am Nat 2023; 202:231-240. [PMID: 37531272 DOI: 10.1086/724840] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 08/04/2023]
Abstract
AbstractSex chromosomes rapidly turn over in several taxonomic groups. Sex chromosome turnover is generally thought to start with the appearance of a new sex-determining gene on an autosome while an old sex-determining gene still exists, followed by the fixation of the new one. However, we do not know how prevalent the transient state is, where multiple sex-determining loci coexist within natural populations. Here, we removed a Y chromosome with a master male-determining gene DMY from medaka fish using high temperature-induced sex-reversed males. After four generations, the genomic characteristics of a sex chromosome were found on one chromosome, which was an autosome in the original population. Thus, the elimination of a master sex-determining locus can reveal a cryptic locus with a possible sex-determining effect, which can be the seed for sex chromosome turnover. Our results suggest that populations that seem to have a single-locus XY system may have other chromosomal regions with sex-determining effects. In conclusion, the coexistence of multiple sex-determining genes in a natural population may be more prevalent than previously thought. Experimental elimination of a master sex-determining locus may serve as a promising method for finding a locus that can be a protosex chromosome.
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5
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Wang D, Li Y, Li M, Yang W, Ma X, Zhang L, Wang Y, Feng Y, Zhang Y, Zhou R, Sanderson BJ, Keefover-Ring K, Yin T, Smart LB, DiFazio SP, Liu J, Olson M, Ma T. Repeated turnovers keep sex chromosomes young in willows. Genome Biol 2022; 23:200. [PMID: 36151581 PMCID: PMC9502649 DOI: 10.1186/s13059-022-02769-w] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2022] [Accepted: 09/08/2022] [Indexed: 01/10/2023] Open
Abstract
Background Salicaceae species have diverse sex determination systems and frequent sex chromosome turnovers. However, compared with poplars, the diversity of sex determination in willows is poorly understood, and little is known about the evolutionary forces driving their turnover. Here, we characterized the sex determination in two Salix species, S. chaenomeloides and S. arbutifolia, which have an XY system on chromosome 7 and 15, respectively. Results Based on the assemblies of their sex determination regions, we found that the sex determination mechanism of willows may have underlying similarities with poplars, both involving intact and/or partial homologs of a type A cytokinin response regulator (RR) gene. Comparative analyses suggested that at least two sex turnover events have occurred in Salix, one preserving the ancestral pattern of male heterogamety, and the other changing heterogametic sex from XY to ZW, which could be partly explained by the “deleterious mutation load” and “sexually antagonistic selection” theoretical models. We hypothesize that these repeated turnovers keep sex chromosomes of willow species in a perpetually young state, leading to limited degeneration. Conclusions Our findings further improve the evolutionary trajectory of sex chromosomes in Salicaceae species, explore the evolutionary forces driving the repeated turnovers of their sex chromosomes, and provide a valuable reference for the study of sex chromosomes in other species. Supplementary Information The online version contains supplementary material available at 10.1186/s13059-022-02769-w.
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Affiliation(s)
- Deyan Wang
- Key Laboratory for Bio-Resource and Eco-Environment of Ministry of Education & Sichuan Zoige Alpine Wetland Ecosystem National Observation and Research Station, College of Life Science, Sichuan University, Chengdu, China
| | - Yiling Li
- Key Laboratory for Bio-Resource and Eco-Environment of Ministry of Education & Sichuan Zoige Alpine Wetland Ecosystem National Observation and Research Station, College of Life Science, Sichuan University, Chengdu, China
| | - Mengmeng Li
- Key Laboratory for Bio-Resource and Eco-Environment of Ministry of Education & Sichuan Zoige Alpine Wetland Ecosystem National Observation and Research Station, College of Life Science, Sichuan University, Chengdu, China
| | - Wenlu Yang
- Key Laboratory for Bio-Resource and Eco-Environment of Ministry of Education & Sichuan Zoige Alpine Wetland Ecosystem National Observation and Research Station, College of Life Science, Sichuan University, Chengdu, China
| | - Xinzhi Ma
- Key Laboratory for Bio-Resource and Eco-Environment of Ministry of Education & Sichuan Zoige Alpine Wetland Ecosystem National Observation and Research Station, College of Life Science, Sichuan University, Chengdu, China
| | - Lei Zhang
- Key Laboratory for Bio-Resource and Eco-Environment of Ministry of Education & Sichuan Zoige Alpine Wetland Ecosystem National Observation and Research Station, College of Life Science, Sichuan University, Chengdu, China
| | - Yubo Wang
- Key Laboratory for Bio-Resource and Eco-Environment of Ministry of Education & Sichuan Zoige Alpine Wetland Ecosystem National Observation and Research Station, College of Life Science, Sichuan University, Chengdu, China
| | - Yanlin Feng
- Key Laboratory for Bio-Resource and Eco-Environment of Ministry of Education & Sichuan Zoige Alpine Wetland Ecosystem National Observation and Research Station, College of Life Science, Sichuan University, Chengdu, China
| | - Yuanyuan Zhang
- Key Laboratory for Bio-Resource and Eco-Environment of Ministry of Education & Sichuan Zoige Alpine Wetland Ecosystem National Observation and Research Station, College of Life Science, Sichuan University, Chengdu, China
| | - Ran Zhou
- Department of Biology, West Virginia University, Morgantown, WV, USA
| | - Brian J Sanderson
- Department of Biology, West Virginia University, Morgantown, WV, USA.,Department of Biological Sciences, Texas Tech University, Lubbock, TX, USA
| | - Ken Keefover-Ring
- Departments of Botany and Geography, University of Wisconsin-Madison, Madison, WI, USA
| | - Tongming Yin
- The Key Laboratory of Tree Genetics and Biotechnology of Jiangsu Province and Education Department of China, Nanjing Forestry University, Nanjing, China
| | - Lawrence B Smart
- Horticulture Section, School of Integrative Plant Science, Cornell University, Cornell AgriTech, Geneva, NY, USA
| | - Stephen P DiFazio
- Department of Biology, West Virginia University, Morgantown, WV, USA
| | - Jianquan Liu
- Key Laboratory for Bio-Resource and Eco-Environment of Ministry of Education & Sichuan Zoige Alpine Wetland Ecosystem National Observation and Research Station, College of Life Science, Sichuan University, Chengdu, China.
| | - Matthew Olson
- Department of Biological Sciences, Texas Tech University, Lubbock, TX, USA.
| | - Tao Ma
- Key Laboratory for Bio-Resource and Eco-Environment of Ministry of Education & Sichuan Zoige Alpine Wetland Ecosystem National Observation and Research Station, College of Life Science, Sichuan University, Chengdu, China.
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6
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Maier MC, McInerney MRA, Graves JAM, Charchar FJ. Noncoding Genes on Sex Chromosomes and Their Function in Sex Determination, Dosage Compensation, Male Traits, and Diseases. Sex Dev 2021; 15:432-440. [PMID: 34794153 DOI: 10.1159/000519622] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2021] [Accepted: 09/13/2021] [Indexed: 11/19/2022] Open
Abstract
The mammalian Y chromosome has evolved in many species into a specialized chromosome that contributes to sex development among other male phenotypes. This function is well studied in terms of protein-coding genes. Less is known about the noncoding genome on the Y chromosome and its contribution to both sex development and other traits. Once considered junk genetic material, noncoding RNAs are now known to contribute to the regulation of gene expression and to play an important role in refining cellular functions. The prime examples are noncoding genes on the X chromosome, which mitigate the differential dosage of genes on sex chromosomes. Here, we discuss the evolution of noncoding RNAs on the Y chromosome and the emerging evidence of how micro, long, and circular noncoding RNAs transcribed from the Y chromosome contribute to sex differentiation. We briefly touch on emerging evidence that these noncoding RNAs also contribute to some other important clinical phenotypes in humans.
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Affiliation(s)
- Michelle C Maier
- Health Innovation & Transformation Centre, Federation University, Mt Helen, Victoria, Australia.,School of Science, Psychology and Sport, Federation University Australia, Ballarat, Victoria, Australia
| | - Molly-Rose A McInerney
- Health Innovation & Transformation Centre, Federation University, Mt Helen, Victoria, Australia.,School of Science, Psychology and Sport, Federation University Australia, Ballarat, Victoria, Australia
| | | | - Fadi J Charchar
- Health Innovation & Transformation Centre, Federation University, Mt Helen, Victoria, Australia.,Department of Cardiovascular Sciences, University of Leicester, Leicester, United Kingdom.,Department of Anatomy and Physiology, University of Melbourne, Melbourne, Victoria, Australia
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7
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Perrin N. Sex-chromosome evolution in frogs: what role for sex-antagonistic genes? Philos Trans R Soc Lond B Biol Sci 2021; 376:20200094. [PMID: 34247502 PMCID: PMC8273499 DOI: 10.1098/rstb.2020.0094] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/08/2020] [Indexed: 02/07/2023] Open
Abstract
Sex-antagonistic (SA) genes are widely considered to be crucial players in the evolution of sex chromosomes, being instrumental in the arrest of recombination and degeneration of Y chromosomes, as well as important drivers of sex-chromosome turnovers. To test such claims, one needs to focus on systems at the early stages of differentiation, ideally with a high turnover rate. Here, I review recent work on two families of amphibians, Ranidae (true frogs) and Hylidae (tree frogs), to show that results gathered so far from these groups provide no support for a significant role of SA genes in the evolutionary dynamics of their sex chromosomes. The findings support instead a central role for neutral processes and deleterious mutations. 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)'.
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Affiliation(s)
- Nicolas Perrin
- Department of Ecology and Evolution, University of Lausanne, 1015 Lausanne, Switzerland
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8
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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] [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)'.
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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
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9
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Sakamoto T, Innan H. Establishment of a new sex-determining allele driven by sexually antagonistic selection. G3-GENES GENOMES GENETICS 2021; 11:6028988. [PMID: 33561232 PMCID: PMC8022746 DOI: 10.1093/g3journal/jkaa031] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/01/2020] [Accepted: 11/24/2020] [Indexed: 12/04/2022]
Abstract
The turnover of sex-determining loci has repeatedly occurred in a number of species, rather than having a diverged pair of sex chromosomes. We model the turnover process by considering a linked locus under sexually antagonistic selection. The entire process of a turnover may be divided into two phases, which are referred to as the stochastic and deterministic phases. The stochastic phase is when a new sex-determining allele just arises and is still rare and random genetic drift plays an important role. In the deterministic phase, the new allele further increases in frequency by positive selection. The theoretical results currently available are for the deterministic phase, which demonstrated that a turnover of a newly arisen sex-determining locus could benefit from selection at a linked locus under sexually antagonistic selection, by assuming that sexually antagonistic selection works in a form of balancing selection. In this work, we provide a comprehensive theoretical description of the entire process from the stochastic phase to the deterministic phase. In addition to balancing selection, we explore several other modes of selection on the linked locus. Our theory allows us make a quantitative argument on the rate of turnover and the effect of the mode of selection at the linked locus. We also performed simulations to explore the pattern of polymorphism around the new sex-determining locus. We find that the pattern of polymorphism is informative to infer how selection worked through the turnover process.
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Affiliation(s)
- Takahiro Sakamoto
- Department of Evolutionary Studies of Biosystems, SOKENDAI, The Graduate University for Advanced Studies, Shonan Village, Hayama, Kanagawa, 240-0193, Japan
| | - Hideki Innan
- Department of Evolutionary Studies of Biosystems, SOKENDAI, The Graduate University for Advanced Studies, Shonan Village, Hayama, Kanagawa, 240-0193, Japan
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10
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Dufresnes C, Brelsford A, Baier F, Perrin N. When Sex Chromosomes Recombine Only in the Heterogametic Sex: Heterochiasmy and Heterogamety in Hyla Tree Frogs. Mol Biol Evol 2021; 38:192-200. [PMID: 32761205 PMCID: PMC7782862 DOI: 10.1093/molbev/msaa201] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Sex chromosomes are classically predicted to stop recombining in the heterogametic sex, thereby enforcing linkage between sex-determining (SD) and sex-antagonistic (SA) genes. With the same rationale, a pre-existing sex asymmetry in recombination is expected to affect the evolution of heterogamety, for example, a low rate of male recombination might favor transitions to XY systems, by generating immediate linkage between SD and SA genes. Furthermore, the accumulation of deleterious mutations on nonrecombining Y chromosomes should favor XY-to-XY transitions (which discard the decayed Y), but disfavor XY-to-ZW transitions (which fix the decayed Y as an autosome). Like many anuran amphibians, Hyla tree frogs have been shown to display drastic heterochiasmy (males only recombine at chromosome tips) and are typically XY, which seems to fit the above expectations. Instead, here we demonstrate that two species, H. sarda and H. savignyi, share a common ZW system since at least 11 Ma. Surprisingly, the typical pattern of restricted male recombination has been maintained since then, despite female heterogamety. Hence, sex chromosomes recombine freely in ZW females, not in ZZ males. This suggests that heterochiasmy does not constrain heterogamety (and vice versa), and that the role of SA genes in the evolution of sex chromosomes might have been overemphasized.
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Affiliation(s)
- Christophe Dufresnes
- LASER, College of Biology and the Environment, Nanjing Forestry University, Nanjing, People's Republic of China
- Department of Ecology and Evolution, University of Lausanne, Lausanne, Switzerland
| | - Alan Brelsford
- Department of Evolution, Ecology, and Organismal Biology, University of California, Riverside, Riverside, CA
| | - Felix Baier
- Department of Molecular and Cellular Biology, Department of Organismic and Evolutionary Biology, Museum of Comparative Zoology, Harvard University, Cambridge, MA
| | - Nicolas Perrin
- Department of Ecology and Evolution, University of Lausanne, Lausanne, Switzerland
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11
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Tao W, Conte MA, Wang D, Kocher TD. Network architecture and sex chromosome turnovers: Do epistatic interactions shape patterns of sex chromosome replacement? Bioessays 2020; 43:e2000161. [PMID: 33283342 DOI: 10.1002/bies.202000161] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2020] [Revised: 11/04/2020] [Accepted: 11/05/2020] [Indexed: 11/11/2022]
Abstract
Recent studies have revealed an astonishing diversity of sex chromosomes in many vertebrate lineages, prompting questions about the mechanisms of sex chromosome turnover. While there is considerable population genetic theory about the evolutionary forces promoting sex chromosome replacement, this theory has not yet been integrated with our understanding of the molecular and developmental genetics of sex determination. Here, we review recent data to examine four questions about how the structure of gene networks influences the evolution of sex determination. We argue that patterns of epistasis, arising from the structure of genetic networks, may play an important role in regulating the rates and patterns of sex chromosome replacement.
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Affiliation(s)
- Wenjing Tao
- Key Laboratory of Freshwater Fish Reproduction and Development (Ministry of Education), Key Laboratory of Aquatic Science of Chongqing, School of Life Sciences, Southwest University, Chongqing, China
| | - Matthew A Conte
- Department of Biology, University of Maryland, College Park, Maryland, USA
| | - Deshou Wang
- Key Laboratory of Freshwater Fish Reproduction and Development (Ministry of Education), Key Laboratory of Aquatic Science of Chongqing, School of Life Sciences, Southwest University, Chongqing, China
| | - Thomas D Kocher
- Department of Biology, University of Maryland, College Park, Maryland, USA
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12
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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] [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.
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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
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Veltsos P, Rodrigues N, Studer T, Ma WJ, Sermier R, Leuenberger J, Perrin N. No evidence that Y-chromosome differentiation affects male fitness in a Swiss population of common frogs. J Evol Biol 2019; 33:401-409. [PMID: 31758728 DOI: 10.1111/jeb.13573] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2019] [Accepted: 11/14/2019] [Indexed: 11/28/2022]
Abstract
The canonical model of sex-chromosome evolution assigns a key role to sexually antagonistic (SA) genes on the arrest of recombination and ensuing degeneration of Y chromosomes. This assumption cannot be tested in organisms with highly differentiated sex chromosomes, such as mammals or birds, owing to the lack of polymorphism. Fixation of SA alleles, furthermore, might be the consequence rather than the cause of recombination arrest. Here we focus on a population of common frogs (Rana temporaria) where XY males with genetically differentiated Y chromosomes (nonrecombinant Y haplotypes) coexist with both XY° males with proto-Y chromosomes (only differentiated from X chromosomes in the immediate vicinity of the candidate sex-determining locus Dmrt1) and XX males with undifferentiated sex chromosomes (genetically identical to XX females). Our study finds no effect of sex-chromosome differentiation on male phenotype, mating success or fathering success. Our conclusions rejoin genomic studies that found no differences in gene expression between XY, XY° and XX males. Sexual dimorphism in common frogs might result more from the differential expression of autosomal genes than from sex-linked SA genes. Among-male variance in sex-chromosome differentiation seems better explained by a polymorphism in the penetrance of alleles at the sex locus, resulting in variable levels of sex reversal (and thus of X-Y recombination in XY females), independent of sex-linked SA genes.
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Affiliation(s)
- Paris Veltsos
- Department of Ecology and Evolution, University of Lausanne, Lausanne, Switzerland
| | - Nicolas Rodrigues
- Department of Ecology and Evolution, University of Lausanne, Lausanne, Switzerland
| | - Tania Studer
- Department of Ecology and Evolution, University of Lausanne, Lausanne, Switzerland
| | - Wen-Juan Ma
- Department of Ecology and Evolution, University of Lausanne, Lausanne, Switzerland
| | - Roberto Sermier
- Department of Ecology and Evolution, University of Lausanne, Lausanne, Switzerland
| | - Julien Leuenberger
- Department of Ecology and Evolution, University of Lausanne, Lausanne, Switzerland
| | - Nicolas Perrin
- Department of Ecology and Evolution, University of Lausanne, Lausanne, Switzerland
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