1
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Cole JM, Scott CB, Johnson MM, Golightly PR, Carlson J, Ming MJ, Harpak A, Kirkpatrick M. The battle of the sexes in humans is highly polygenic. Proc Natl Acad Sci U S A 2024; 121:e2412315121. [PMID: 39302970 DOI: 10.1073/pnas.2412315121] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2024] [Accepted: 08/21/2024] [Indexed: 09/22/2024] Open
Abstract
Sex-differential selection (SDS), which occurs when the fitness effects of alleles differ between males and females, can have profound impacts on the maintenance of genetic variation, disease risk, and other key aspects of natural populations. Because the sexes mix their autosomal genomes each generation, quantifying SDS is not possible using conventional population genetic approaches. Here, we introduce a method that exploits subtle sex differences in haplotype frequencies resulting from SDS acting in the current generation. Using data from 300K individuals in the UK Biobank, we estimate the strength of SDS throughout the genome. While only a handful of loci under SDS are individually significant, we uncover highly polygenic signals of genome-wide SDS for both viability and fecundity. Selection coefficients of [Formula: see text] may be typical. Despite its ubiquity, SDS may impose a mortality load of less than 1%. An interesting life-history tradeoff emerges: Alleles that increase viability more strongly in females than males tend to increase fecundity more strongly in males than in females. Finally, we find marginal evidence of SDS on fecundity acting on alleles affecting arm fat-free mass. Taken together, our findings connect the long-standing evidence of SDS acting on human phenotypes with its impact on the genome.
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Affiliation(s)
- Jared M Cole
- Department of Integrative Biology, University of Texas at Austin, Austin, TX 78712
- Department of Population Health, University of Texas at Austin, Austin, TX 78712
| | - Carly B Scott
- Department of Biology, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599
| | - Mackenzie M Johnson
- Computational Biology Program, Public Health Sciences Division, Fred Hutchinson Cancer Center, Seattle, WA 98109
| | - Peter R Golightly
- Department of Integrative Biology, University of Texas at Austin, Austin, TX 78712
| | - Jedidiah Carlson
- Department of Integrative Biology, University of Texas at Austin, Austin, TX 78712
- Department of Population Health, University of Texas at Austin, Austin, TX 78712
| | - Matthew J Ming
- Department of Integrative Biology, University of Texas at Austin, Austin, TX 78712
- Department of Population Health, University of Texas at Austin, Austin, TX 78712
| | - Arbel Harpak
- Department of Integrative Biology, University of Texas at Austin, Austin, TX 78712
- Department of Population Health, University of Texas at Austin, Austin, TX 78712
| | - Mark Kirkpatrick
- Department of Integrative Biology, University of Texas at Austin, Austin, TX 78712
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2
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Wang D, Rastas P, Yi X, Löytynoja A, Kivikoski M, Feng X, Reid K, Merilä J. Improved assembly of the Pungitius pungitius reference genome. G3 (BETHESDA, MD.) 2024; 14:jkae126. [PMID: 38861393 PMCID: PMC11304971 DOI: 10.1093/g3journal/jkae126] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/24/2024] [Revised: 05/23/2024] [Accepted: 05/30/2024] [Indexed: 06/13/2024]
Abstract
The nine-spined stickleback (Pungitius pungitius) has been increasingly used as a model system in studies of local adaptation and sex chromosome evolution but its current reference genome assembly is far from perfect, lacking distinct sex chromosomes. We generated an improved assembly of the nine-spined stickleback reference genome (98.3% BUSCO completeness) with the aid of linked-read mapping. While the new assembly (v8) was of similar size as the earlier version (v7), we were able to assign 4.4 times more contigs to the linkage groups and improve the contiguity of the genome. Moreover, the new assembly contains a ∼22.8 Mb Y-linked scaffold (LG22) consisting mainly of previously assigned X-contigs, putative Y-contigs, putative centromere contigs, and highly repetitive elements. The male individual showed an even mapping depth on LG12 (pseudo X chromosome) and LG22 (Y-linked scaffold) in the segregating sites, suggesting near-pure X and Y representation in the v8 assembly. A total of 26,803 genes were annotated, and about 33% of the assembly was found to consist of repetitive elements. The high proportion of repetitive elements in LG22 (53.10%) suggests it can be difficult to assemble the complete sequence of the species' Y chromosome. Nevertheless, the new assembly is a significant improvement over the previous version and should provide a valuable resource for genomic studies of stickleback fishes.
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Affiliation(s)
- Dandan Wang
- Area of Ecology and Biodiversity, School of Biological Sciences, The University of Hong Kong, 999077, Hong Kong SAR
| | - Pasi Rastas
- Institute of Biotechnology, University of Helsinki, Helsinki FI-00014, Finland
| | - Xueling Yi
- Area of Ecology and Biodiversity, School of Biological Sciences, The University of Hong Kong, 999077, Hong Kong SAR
| | - Ari Löytynoja
- Institute of Biotechnology, University of Helsinki, Helsinki FI-00014, Finland
- Organismal and Evolutionary Biology Research Programme, Faculty of Biological and Environmental Sciences, University of Helsinki, Helsinki FI-00014, Finland
| | - Mikko Kivikoski
- Ecological Genetics Research Unit, Organismal and Evolutionary Biology Research Programme, Faculty of Biological and Environmental Sciences, University of Helsinki, Helsinki FI-00014, Finland
- Department of Computer Science, University of Helsinki, Helsinki FI-00014, Finland
| | - Xueyun Feng
- Institute of Biotechnology, University of Helsinki, Helsinki FI-00014, Finland
- Ecological Genetics Research Unit, Organismal and Evolutionary Biology Research Programme, Faculty of Biological and Environmental Sciences, University of Helsinki, Helsinki FI-00014, Finland
| | - Kerry Reid
- Area of Ecology and Biodiversity, School of Biological Sciences, The University of Hong Kong, 999077, Hong Kong SAR
| | - Juha Merilä
- Area of Ecology and Biodiversity, School of Biological Sciences, The University of Hong Kong, 999077, Hong Kong SAR
- Ecological Genetics Research Unit, Organismal and Evolutionary Biology Research Programme, Faculty of Biological and Environmental Sciences, University of Helsinki, Helsinki FI-00014, Finland
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3
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VanKuren NW, Chen J, Long M. Sexual conflict drive in the rapid evolution of new gametogenesis genes. Semin Cell Dev Biol 2024; 159-160:27-37. [PMID: 38309142 DOI: 10.1016/j.semcdb.2024.01.005] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2023] [Revised: 01/19/2024] [Accepted: 01/19/2024] [Indexed: 02/05/2024]
Abstract
The evolutionary forces underlying the rapid evolution in sequences and functions of new genes remain a mystery. Adaptation by natural selection explains the evolution of some new genes. However, many new genes perform sex-biased functions that have rapidly evolved over short evolutionary time scales, suggesting that new gene evolution may often be driven by conflicting selective pressures on males and females. It is well established that such sexual conflict (SC) plays a central role in maintaining phenotypic and genetic variation within populations, but the role of SC in driving new gene evolution remains essentially unknown. This review explores the connections between SC and new gene evolution through discussions of the concept of SC, the phenotypic and genetic signatures of SC in evolving populations, and the molecular mechanisms by which SC could drive the evolution of new genes. We synthesize recent work in this area with a discussion of the case of Apollo and Artemis, two extremely young genes (<200,000 years) in Drosophila melanogaster, which offered the first empirical insights into the evolutionary process by which SC could drive the evolution of new genes. These new duplicate genes exhibit the hallmarks of sexually antagonistic selection: rapid DNA and protein sequence evolution, essential sex-specific functions in gametogenesis, and complementary sex-biased expression patterns. Importantly, Apollo is essential for male fitness but detrimental to female fitness, while Artemis is essential for female fitness but detrimental to male fitness. These sexually antagonistic fitness effects and complementary changes to expression, sequence, and function suggest that these duplicates were selected for mitigating SC, but that SC has not been fully resolved. Finally, we propose Sexual Conflict Drive as a self-driven model to interpret the rapid evolution of new genes, explain the potential for SC and sexually antagonistic selection to contribute to long-term evolution, and suggest its utility for understanding the rapid evolution of new genes in gametogenesis.
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Affiliation(s)
- Nicholas W VanKuren
- Department of Ecology and Evolution, The University of Chicago, United States.
| | - Jianhai Chen
- Department of Ecology and Evolution, The University of Chicago, United States
| | - Manyuan Long
- Department of Ecology and Evolution, The University of Chicago, United States.
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4
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Glaser-Schmitt A, Ramnarine TJS, Parsch J. Rapid evolutionary change, constraints and the maintenance of polymorphism in natural populations of Drosophila melanogaster. Mol Ecol 2024; 33:e17024. [PMID: 37222070 DOI: 10.1111/mec.17024] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2022] [Revised: 04/28/2023] [Accepted: 05/05/2023] [Indexed: 05/25/2023]
Abstract
Allele frequencies can shift rapidly within natural populations. Under certain conditions, repeated rapid allele frequency shifts can lead to the long-term maintenance of polymorphism. In recent years, studies of the model insect Drosophila melanogaster have suggested that this phenomenon is more common than previously believed and is often driven by some form of balancing selection, such as temporally fluctuating or sexually antagonistic selection. Here we discuss some of the general insights into rapid evolutionary change revealed by large-scale population genomic studies, as well as the functional and mechanistic causes of rapid adaptation uncovered by single-gene studies. As an example of the latter, we consider a regulatory polymorphism of the D. melanogaster fezzik gene. Polymorphism at this site has been maintained at intermediate frequency over an extended period of time. Regular observations from a single population over a period of 7 years revealed significant differences in the frequency of the derived allele and its variance across collections between the sexes. These patterns are highly unlikely to arise from genetic drift alone or from the action of sexually antagonistic or temporally fluctuating selection individually. Instead, the joint action of sexually antagonistic and temporally fluctuating selection can best explain the observed rapid and repeated allele frequency shifts. Temporal studies such as those reviewed here further our understanding of how rapid changes in selection can lead to the long-term maintenance of polymorphism as well as improve our knowledge of the forces driving and limiting adaptation in nature.
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Affiliation(s)
- Amanda Glaser-Schmitt
- Division of Evolutionary Biology, Faculty of Biology, Ludwig-Maximilians-Universität München, Munich, Germany
| | - Timothy J S Ramnarine
- Division of Evolutionary Biology, Faculty of Biology, Ludwig-Maximilians-Universität München, Munich, Germany
| | - John Parsch
- Division of Evolutionary Biology, Faculty of Biology, Ludwig-Maximilians-Universität München, Munich, Germany
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5
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Smith SH, Hsiung K, Böhne A. Evaluating the role of sexual antagonism in the evolution of sex chromosomes: new data from fish. Curr Opin Genet Dev 2023; 81:102078. [PMID: 37379742 DOI: 10.1016/j.gde.2023.102078] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2023] [Revised: 06/07/2023] [Accepted: 06/07/2023] [Indexed: 06/30/2023]
Abstract
The recent increase in available molecular and genomic data for diverse taxa helps to shed new light on long-standing theories. Research into sex chromosome evolution has particularly benefited from a growing number of studies of fish, motivated by their highly diverse mechanisms of sex determination. Sexual antagonism is regularly cited as an influential force in sex chromosome emergence; however, this so far proves difficult to demonstrate. In this review, we highlight recent developments in the investigation of sexual antagonism in sex chromosome research in fish. We find strong emphasis placed on study-organism specific genomic features and patterns of recombination, rather than evidence for a comprehensive role of sexual antagonism. In this light, we discuss the alternative models of sex chromosome evolution. We conclude that fish represents a key resource for further research, provided attention is given to species-specific effects while simultaneously integrating comparative studies across taxa for a vital and comprehensive understanding of sex chromosome evolution and investigation of proposed models.
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Affiliation(s)
- Sophie Helen Smith
- Centre for Molecular Biodiversity Research, Leibniz Institute for the Analysis of Biodiversity Change, Museum Koenig Bonn, Adenauerallee 127, 53113 Bonn, Germany. https://twitter.com/@shg_smith
| | - Kevin Hsiung
- Centre for Molecular Biodiversity Research, Leibniz Institute for the Analysis of Biodiversity Change, Museum Koenig Bonn, Adenauerallee 127, 53113 Bonn, Germany. https://twitter.com/@KevinKHsiung
| | - Astrid Böhne
- Centre for Molecular Biodiversity Research, Leibniz Institute for the Analysis of Biodiversity Change, Museum Koenig Bonn, Adenauerallee 127, 53113 Bonn, Germany.
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6
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Zhu C, Ming MJ, Cole JM, Edge MD, Kirkpatrick M, Harpak A. Amplification is the primary mode of gene-by-sex interaction in complex human traits. CELL GENOMICS 2023; 3:100297. [PMID: 37228747 PMCID: PMC10203050 DOI: 10.1016/j.xgen.2023.100297] [Citation(s) in RCA: 22] [Impact Index Per Article: 22.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 05/16/2022] [Revised: 12/15/2022] [Accepted: 03/13/2023] [Indexed: 05/27/2023]
Abstract
Sex differences in complex traits are suspected to be in part due to widespread gene-by-sex interactions (GxSex), but empirical evidence has been elusive. Here, we infer the mixture of ways in which polygenic effects on physiological traits covary between males and females. We find that GxSex is pervasive but acts primarily through systematic sex differences in the magnitude of many genetic effects ("amplification") rather than in the identity of causal variants. Amplification patterns account for sex differences in trait variance. In some cases, testosterone may mediate amplification. Finally, we develop a population-genetic test linking GxSex to contemporary natural selection and find evidence of sexually antagonistic selection on variants affecting testosterone levels. Our results suggest that amplification of polygenic effects is a common mode of GxSex that may contribute to sex differences and fuel their evolution.
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Affiliation(s)
- Carrie Zhu
- Department of Population Health, The University of Texas at Austin, Austin, TX, USA
- Department of Integrative Biology, The University of Texas at Austin, Austin, TX, USA
| | - Matthew J. Ming
- Department of Population Health, The University of Texas at Austin, Austin, TX, USA
- Department of Integrative Biology, The University of Texas at Austin, Austin, TX, USA
| | - Jared M. Cole
- Department of Population Health, The University of Texas at Austin, Austin, TX, USA
- Department of Integrative Biology, The University of Texas at Austin, Austin, TX, USA
| | - Michael D. Edge
- Department of Quantitative and Computational Biology, University of Southern California, Los Angeles, CA, USA
| | - Mark Kirkpatrick
- Department of Integrative Biology, The University of Texas at Austin, Austin, TX, USA
| | - Arbel Harpak
- Department of Population Health, The University of Texas at Austin, Austin, TX, USA
- Department of Integrative Biology, The University of Texas at Austin, Austin, TX, USA
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7
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Singh P, Taborsky M, Peichel CL, Sturmbauer C. Genomic basis of Y-linked dwarfism in cichlids pursuing alternative reproductive tactics. Mol Ecol 2023; 32:1592-1607. [PMID: 36588349 DOI: 10.1111/mec.16839] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2021] [Revised: 12/08/2022] [Accepted: 12/19/2022] [Indexed: 01/03/2023]
Abstract
Sexually antagonistic selection, which favours different optima in males and females, is predicted to play an important role in the evolution of sex chromosomes. Body size is a sexually antagonistic trait in the shell-brooding cichlid fish Lamprologous callipterus, as "bourgeois" males must be large enough to carry empty snail shells to build nests whereas females must be small enough to fit into shells for breeding. In this species, there is also a second male morph: smaller "dwarf" males employ an alternative reproductive strategy by wriggling past spawning females into shells to fertilize eggs. L. callipterus male morphology is passed strictly from father to son, suggesting Y-linkage. However, sex chromosomes had not been previously identified in this species, and the genomic basis of size dimorphism was unknown. Here we used whole-genome sequencing to identify a 2.4-Mb sex-linked region on scaffold_23 with reduced coverage and single nucleotide polymorphism density in both male morphs compared to females. Within this sex region, distinct Y-haplotypes delineate the two male morphs, and candidate genes for body size (GHRHR, a known dwarfism gene) and sex determination (ADCYAP1R1) are in high linkage disequilibrium. Because differences in body size between females and males are under strong selection in L. callipterus, we hypothesize that sexual antagonism over body size initiated early events in sex chromosome evolution, followed by Y divergence to give rise to bourgeois and dwarf male reproductive strategies. Our results are consistent with the hypothesis that sexually antagonistic traits should be linked to young sex chromosomes.
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Affiliation(s)
- Pooja Singh
- Institute of Biology, University of Graz, Graz, Austria.,Aquatic Ecology Division, Institute of Ecology and Evolution, University of Bern, Bern, Switzerland.,Swiss Federal Institute of Aquatic Science and Technology (EAWAG), Kastanienbaum, Switzerland
| | - Michael Taborsky
- Behavioural Ecology Division, Institute of Ecology and Evolution, University of Bern, Switzerland.,Max Planck Institute of Animal Behavior, Constance, Germany.,Institute for Advanced Study (Wissenschaftskolleg) Berlin, Berlin, Germany
| | - Catherine L Peichel
- Evolutionary Ecology Division, Institute of Ecology and Evolution, University of Bern, Bern, Switzerland
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8
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Ruzicka F, Holman L, Connallon T. Polygenic signals of sex differences in selection in humans from the UK Biobank. PLoS Biol 2022; 20:e3001768. [PMID: 36067235 PMCID: PMC9481184 DOI: 10.1371/journal.pbio.3001768] [Citation(s) in RCA: 4] [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: 09/30/2021] [Revised: 09/16/2022] [Accepted: 07/27/2022] [Indexed: 11/19/2022] Open
Abstract
Sex differences in the fitness effects of genetic variants can influence the rate of adaptation and the maintenance of genetic variation. For example, "sexually antagonistic" (SA) variants, which are beneficial for one sex and harmful for the other, can both constrain adaptation and increase genetic variability for fitness components such as survival, fertility, and disease susceptibility. However, detecting variants with sex-differential fitness effects is difficult, requiring genome sequences and fitness measurements from large numbers of individuals. Here, we develop new theory for studying sex-differential selection across a complete life cycle and test our models with genotypic and reproductive success data from approximately 250,000 UK Biobank individuals. We uncover polygenic signals of sex-differential selection affecting survival, reproductive success, and overall fitness, with signals of sex-differential reproductive selection reflecting a combination of SA polymorphisms and sexually concordant polymorphisms in which the strength of selection differs between the sexes. Moreover, these signals hold up to rigorous controls that minimise the contributions of potential confounders, including sequence mapping errors, population structure, and ascertainment bias. Functional analyses reveal that sex-differentiated sites are enriched in phenotype-altering genomic regions, including coding regions and loci affecting a range of quantitative traits. Population genetic analyses show that sex-differentiated sites exhibit evolutionary histories dominated by genetic drift and/or transient balancing selection, but not long-term balancing selection, which is consistent with theoretical predictions of effectively weak SA balancing selection in historically small populations. Overall, our results are consistent with polygenic sex-differential-including SA-selection in humans. Evidence for sex-differential selection is particularly strong for variants affecting reproductive success, in which the potential contributions of nonrandom sampling to signals of sex differentiation can be excluded.
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Affiliation(s)
- Filip Ruzicka
- School of Biological Sciences, Monash University, Clayton, Victoria, Australia
| | - Luke Holman
- School of BioSciences, University of Melbourne, Parkville, Victoria, Australia
- School of Applied Sciences, Edinburgh Napier University, Edinburgh, United Kingdom
| | - Tim Connallon
- School of Biological Sciences, Monash University, Clayton, Victoria, Australia
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9
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Dagilis AJ, Sardell JM, Josephson MP, Su Y, Kirkpatrick M, Peichel CL. Searching for signatures of sexually antagonistic selection on stickleback sex chromosomes. Philos Trans R Soc Lond B Biol Sci 2022; 377:20210205. [PMID: 35694749 PMCID: PMC9189504 DOI: 10.1098/rstb.2021.0205] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
Intralocus sexually antagonistic selection occurs when an allele is beneficial to one sex but detrimental to the other. This form of selection is thought to be key to the evolution of sex chromosomes but is hard to detect. Here we perform an analysis of phased young sex chromosomes to look for signals of sexually antagonistic selection in the Japan Sea stickleback (Gasterosteus nipponicus). Phasing allows us to date the suppression of recombination on the sex chromosome and provides unprecedented resolution to identify sexually antagonistic selection in the recombining region of the chromosome. We identify four windows with elevated divergence between the X and Y in the recombining region, all in or very near genes associated with phenotypes potentially under sexually antagonistic selection in humans. We are unable, however, to rule out the alternative hypothesis that the peaks of divergence result from demographic effects. Thus, although sexually antagonistic selection is a key hypothesis for the formation of supergenes on sex chromosomes, it remains challenging to detect. This article is part of the theme issue ‘Genomic architecture of supergenes: causes and evolutionary consequences’.
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Affiliation(s)
- Andrius J Dagilis
- Department of Integrative Biology, University of Texas, Austin TX 78712, USA.,Department of Biology, University of North Carolina, Chapel Hill, NC 27599, USA
| | - Jason M Sardell
- Department of Integrative Biology, University of Texas, Austin TX 78712, USA
| | - Matthew P Josephson
- Division of Evolutionary Ecology, Institute of Ecology and Evolution, University of Bern, 3012 Bern, Switzerland
| | - Yiheng Su
- Department of Computer Science, University of Texas, Austin TX 78712, USA
| | - Mark Kirkpatrick
- Department of Integrative Biology, University of Texas, Austin TX 78712, USA
| | - Catherine L Peichel
- Division of Evolutionary Ecology, Institute of Ecology and Evolution, University of Bern, 3012 Bern, Switzerland
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10
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Laurentino TG, Boileau N, Ronco F, Berner D. The ectodysplasin-A receptor is a candidate gene for lateral plate number variation in stickleback fish. G3 (BETHESDA, MD.) 2022; 12:jkac077. [PMID: 35377433 PMCID: PMC9157104 DOI: 10.1093/g3journal/jkac077] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/23/2021] [Accepted: 03/28/2022] [Indexed: 02/04/2023]
Abstract
Variation in lateral plating in stickleback fish represents a classical example of rapid and parallel adaptation in morphology. The underlying genetic architecture involves polymorphism at the ectodysplasin-A gene (EDA). However, lateral plate number is influenced by additional loci that remain poorly characterized. Here, we search for such loci by performing genome-wide differentiation mapping based on pooled whole-genome sequence data from a European stickleback population variable in the extent of lateral plating, while tightly controlling for the phenotypic effect of EDA. This suggests a new candidate locus, the EDA receptor gene (EDAR), for which additional support is obtained by individual-level targeted Sanger sequencing and by comparing allele frequencies among natural populations. Overall, our study illustrates the power of pooled whole-genome sequencing for searching phenotypically relevant loci and opens opportunities for exploring the population genetics and ecological significance of a new candidate locus for stickleback armor evolution.
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Affiliation(s)
- Telma G Laurentino
- Department of Environmental Sciences, Zoology, University of Basel, 4051 Basel, Switzerland
- Department of Environmental Science, Policy, and Management, University of California, Berkeley, CA 94720, USA
| | - Nicolas Boileau
- Department of Environmental Sciences, Zoology, University of Basel, 4051 Basel, Switzerland
| | - Fabrizia Ronco
- Department of Environmental Sciences, Zoology, University of Basel, 4051 Basel, Switzerland
| | - Daniel Berner
- Department of Environmental Sciences, Zoology, University of Basel, 4051 Basel, Switzerland
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11
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Delph LF, Brown KE, Ríos LD, Kelly JK. Sex‐specific natural selection on SNPs in
Silene latifolia. Evol Lett 2022; 6:308-318. [PMID: 35937470 PMCID: PMC9346077 DOI: 10.1002/evl3.283] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2021] [Revised: 02/24/2022] [Accepted: 03/13/2022] [Indexed: 01/15/2023] Open
Affiliation(s)
- Lynda F. Delph
- Department of Biology Indiana University Bloomington Indiana USA
| | - Keely E. Brown
- Department of Ecology and Evolutionary Biology University of Kansas Lawrence Kansas USA
| | - Luis Diego Ríos
- Department of Biology Indiana University Bloomington Indiana USA
| | - John K. Kelly
- Department of Ecology and Evolutionary Biology University of Kansas Lawrence Kansas USA
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12
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Paris JR, Whiting JR, Daniel MJ, Ferrer Obiol J, Parsons PJ, van der Zee MJ, Wheat CW, Hughes KA, Fraser BA. A large and diverse autosomal haplotype is associated with sex-linked colour polymorphism in the guppy. Nat Commun 2022; 13:1233. [PMID: 35264556 PMCID: PMC8907176 DOI: 10.1038/s41467-022-28895-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2021] [Accepted: 02/16/2022] [Indexed: 11/22/2022] Open
Abstract
Male colour patterns of the Trinidadian guppy (Poecilia reticulata) are typified by extreme variation governed by both natural and sexual selection. Since guppy colour patterns are often inherited faithfully from fathers to sons, it has been hypothesised that many of the colour trait genes must be physically linked to sex determining loci as a ‘supergene’ on the sex chromosome. Here, we phenotype and genotype four guppy ‘Iso-Y lines’, where colour was inherited along the patriline for 40 generations. Using an unbiased phenotyping method, we confirm the breeding design was successful in creating four distinct colour patterns. We find that genetic differentiation among the Iso-Y lines is repeatedly associated with a diverse haplotype on an autosome (LG1), not the sex chromosome (LG12). Moreover, the LG1 haplotype exhibits elevated linkage disequilibrium and evidence of sex-specific diversity in the natural source population. We hypothesise that colour pattern polymorphism is driven by Y-autosome epistasis. Extreme colour pattern variation in male Trinidadian guppies are influenced by natural selection and sexual selection. Here, the authors phenotype and genotype four guppy lineages finding that colour pattern is associated with a diverse haplotype on an autosome.
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Affiliation(s)
- Josephine R Paris
- Department of Biosciences, University of Exeter, Stocker Road, Exeter, EX4 4QD, UK.
| | - James R Whiting
- Department of Biosciences, University of Exeter, Stocker Road, Exeter, EX4 4QD, UK
| | - Mitchel J Daniel
- Department of Biological Science, Florida State University, 319 Stadium Drive, Tallahassee, FL, 32304, USA
| | - Joan Ferrer Obiol
- Departament de Microbiologia, Genètica i Estadística and Institut de Recerca de la Biodiversitat, Universitat de Barcelona, Barcelona, Catalonia, Spain
| | - Paul J Parsons
- Department of Biosciences, University of Exeter, Stocker Road, Exeter, EX4 4QD, UK.,NERC Environmental Omics Facility, School of Biosciences, University of Sheffield, Sheffield, S10 2TN, UK
| | - Mijke J van der Zee
- Department of Biosciences, University of Exeter, Stocker Road, Exeter, EX4 4QD, UK
| | | | - Kimberly A Hughes
- Department of Biological Science, Florida State University, 319 Stadium Drive, Tallahassee, FL, 32304, USA
| | - Bonnie A Fraser
- Department of Biosciences, University of Exeter, Stocker Road, Exeter, EX4 4QD, UK
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13
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Ruzicka F, Connallon T. An unbiased test reveals no enrichment of sexually antagonistic polymorphisms on the human X chromosome. Proc Biol Sci 2022; 289:20212314. [PMID: 35078366 PMCID: PMC8790371 DOI: 10.1098/rspb.2021.2314] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2021] [Accepted: 12/21/2021] [Indexed: 01/07/2023] Open
Abstract
Mutations with beneficial effects in one sex can have deleterious effects in the other. Such 'sexually antagonistic' (SA) variants contribute to variation in life-history traits and overall fitness, yet their genomic distribution is poorly resolved. Theory predicts that SA variants could be enriched on the X chromosome or autosomes, yet current empirical tests face two formidable challenges: (i) identifying SA selection in genomic data is difficult; and (ii) metrics of SA variation show persistent biases towards the X, even when SA variants are randomly distributed across the genome. Here, we present an unbiased test of the theory that SA variants are enriched on the X. We first develop models for reproductive FST-a metric for quantifying sex-differential (including SA) effects of genetic variants on lifetime reproductive success-that control for X-linked biases. Comparing data from approximately 250 000 UK Biobank individuals to our models, we find FST elevations consistent with both X-linked and autosomal SA polymorphisms affecting reproductive success in humans. However, the extent of FST elevations does not differ from a model in which SA polymorphisms are randomly distributed across the genome. We argue that the polygenic nature of SA variation, along with sex asymmetries in SA effects, might render X-linked enrichment of SA polymorphisms unlikely.
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Affiliation(s)
- Filip Ruzicka
- School of Biological Sciences, Monash University, Clayton, Victoria, Australia
| | - Tim Connallon
- School of Biological Sciences, Monash University, Clayton, Victoria, Australia
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14
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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] [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.
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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
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15
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Sardell JM, Josephson MP, Dalziel AC, Peichel CL, Kirkpatrick M. Heterogeneous Histories of Recombination Suppression on Stickleback Sex Chromosomes. Mol Biol Evol 2021; 38:4403-4418. [PMID: 34117766 PMCID: PMC8476171 DOI: 10.1093/molbev/msab179] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
How consistent are the evolutionary trajectories of sex chromosomes shortly after they form? Insights into the evolution of recombination, differentiation, and degeneration can be provided by comparing closely related species with homologous sex chromosomes. The sex chromosomes of the threespine stickleback (Gasterosteus aculeatus) and its sister species, the Japan Sea stickleback (G. nipponicus), have been well characterized. Little is known, however, about the sex chromosomes of their congener, the blackspotted stickleback (G. wheatlandi). We used pedigrees to obtain experimentally phased whole genome sequences from blackspotted stickleback X and Y chromosomes. Using multispecies gene trees and analysis of shared duplications, we demonstrate that Chromosome 19 is the ancestral sex chromosome and that its oldest stratum evolved in the common ancestor of the genus. After the blackspotted lineage diverged, its sex chromosomes experienced independent and more extensive recombination suppression, greater X-Y differentiation, and a much higher rate of Y degeneration than the other two species. These patterns may result from a smaller effective population size in the blackspotted stickleback. A recent fusion between the ancestral blackspotted stickleback Y chromosome and Chromosome 12, which produced a neo-X and neo-Y, may have been favored by the very small size of the recombining region on the ancestral sex chromosome. We identify six strata on the ancestral and neo-sex chromosomes where recombination between the X and Y ceased at different times. These results confirm that sex chromosomes can evolve large differences within and between species over short evolutionary timescales.
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Affiliation(s)
- Jason M Sardell
- Department of Integrative Biology, University of Texas at Austin, Austin, TX, USA
| | | | - Anne C Dalziel
- Department of Biology, Saint Mary’s University, Halifax, NS, Canada
| | | | - Mark Kirkpatrick
- Department of Integrative Biology, University of Texas at Austin, Austin, TX, USA
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16
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Fraser BA, Whiting JR, Paris JR, Weadick CJ, Parsons PJ, Charlesworth D, Bergero R, Bemm F, Hoffmann M, Kottler VA, Liu C, Dreyer C, Weigel D. Improved Reference Genome Uncovers Novel Sex-Linked Regions in the Guppy (Poecilia reticulata). Genome Biol Evol 2021; 12:1789-1805. [PMID: 32853348 PMCID: PMC7643365 DOI: 10.1093/gbe/evaa187] [Citation(s) in RCA: 25] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/24/2020] [Indexed: 02/06/2023] Open
Abstract
Theory predicts that the sexes can achieve greater fitness if loci with sexually antagonistic polymorphisms become linked to the sex determining loci, and this can favor the spread of reduced recombination around sex determining regions. Given that sex-linked regions are frequently repetitive and highly heterozygous, few complete Y chromosome assemblies are available to test these ideas. The guppy system (Poecilia reticulata) has long been invoked as an example of sex chromosome formation resulting from sexual conflict. Early genetics studies revealed that male color patterning genes are mostly but not entirely Y-linked, and that X-linkage may be most common in low-predation populations. More recent population genomic studies of guppies have reached varying conclusions about the size and placement of the Y-linked region. However, this previous work used a reference genome assembled from short-read sequences from a female guppy. Here, we present a new guppy reference genome assembly from a male, using long-read PacBio single-molecule real-time sequencing and chromosome contact information. Our new assembly sequences across repeat- and GC-rich regions and thus closes gaps and corrects mis-assemblies found in the short-read female-derived guppy genome. Using this improved reference genome, we then employed broad population sampling to detect sex differences across the genome. We identified two small regions that showed consistent male-specific signals. Moreover, our results help reconcile the contradictory conclusions put forth by past population genomic studies of the guppy sex chromosome. Our results are consistent with a small Y-specific region and rare recombination in male guppies.
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Affiliation(s)
| | | | | | | | | | - Deborah Charlesworth
- Institute of Evolutionary Biology, School of Biological Sciences, University of Edinburgh, United Kingdom
| | - Roberta Bergero
- Institute of Evolutionary Biology, School of Biological Sciences, University of Edinburgh, United Kingdom
| | - Felix Bemm
- Department of Molecular Biology, Max Planck Institute for Developmental Biology, Tübingen, Germany
| | - Margarete Hoffmann
- Department of Molecular Biology, Max Planck Institute for Developmental Biology, Tübingen, Germany
| | - Verena A Kottler
- Department of Molecular Biology, Max Planck Institute for Developmental Biology, Tübingen, Germany
| | - Chang Liu
- Department of Molecular Biology, Max Planck Institute for Developmental Biology, Tübingen, Germany.,Institute of Biology, University of Hohenheim, Stuttgart, Germany
| | - Christine Dreyer
- Department of Molecular Biology, Max Planck Institute for Developmental Biology, Tübingen, Germany
| | - Detlef Weigel
- Department of Molecular Biology, Max Planck Institute for Developmental Biology, Tübingen, Germany
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17
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Artamonova VS, Bardukov NV, Golovin PV, Ivanova TS, Ivanov MV, Lajus DL, Makhrov AA. Determination of the Female-Biased Sex Ratio in Some Young-of-the-Year and Spawner Samples of the Threespine Stickleback Gasterosteus aculeatus by Environmental, Not Genetic, Factors. BIOL BULL+ 2021. [DOI: 10.1134/s1062359021050034] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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18
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Kasimatis KR, Abraham A, Ralph PL, Kern AD, Capra JA, Phillips PC. Evaluating human autosomal loci for sexually antagonistic viability selection in two large biobanks. Genetics 2021; 217:1-10. [PMID: 33683357 DOI: 10.1093/genetics/iyaa015] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2020] [Accepted: 11/15/2020] [Indexed: 12/16/2022] Open
Abstract
Sex and sexual differentiation are pervasive across the tree of life. Because females and males often have substantially different functional requirements, we expect selection to differ between the sexes. Recent studies in diverse species, including humans, suggest that sexually antagonistic viability selection creates allele frequency differences between the sexes at many different loci. However, theory and population-level simulations indicate that sex-specific differences in viability would need to be very large to produce and maintain reported levels of between-sex allelic differentiation. We address this contradiction between theoretical predictions and empirical observations by evaluating evidence for sexually antagonistic viability selection on autosomal loci in humans using the largest cohort to date (UK Biobank, n = 487,999) along with a second large, independent cohort (BioVU, n = 93,864). We performed association tests between genetically ascertained sex and autosomal loci. Although we found dozens of genome-wide significant associations, none replicated across cohorts. Moreover, closer inspection revealed that all associations are likely due to cross-hybridization with sex chromosome regions during genotyping. We report loci with potential for mis-hybridization found on commonly used genotyping platforms that should be carefully considered in future genetic studies of sex-specific differences. Despite being well powered to detect allele frequency differences of up to 0.8% between the sexes, we do not detect clear evidence for this signature of sexually antagonistic viability selection on autosomal variation. These findings suggest a lack of strong ongoing sexually antagonistic viability selection acting on single locus autosomal variation in humans.
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Affiliation(s)
- Katja R Kasimatis
- Institute of Ecology and Evolution, University of Oregon, Eugene, OR 97403, USA
- Department of Ecology and Evolutionary Biology, University of Toronto, Toronto, ON M5S 3B2, Canada
| | - Abin Abraham
- Vanderbilt Genetics Institute, Vanderbilt University Medical Center, Nashville, TN 37232, USA
| | - Peter L Ralph
- Institute of Ecology and Evolution, University of Oregon, Eugene, OR 97403, USA
| | - Andrew D Kern
- Institute of Ecology and Evolution, University of Oregon, Eugene, OR 97403, USA
| | - John A Capra
- Vanderbilt Genetics Institute, Vanderbilt University Medical Center, Nashville, TN 37232, USA
- Department of Biological Sciences, Vanderbilt University, Nashville, TN 37235, USA
- Bakar Computational Health Sciences Institute, Department of Epidemiology and Biostatistics, University of California, San Francisco, CA 94143, USA
| | - Patrick C Phillips
- Institute of Ecology and Evolution, University of Oregon, Eugene, OR 97403, USA
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19
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Glaser-Schmitt A, Wittmann MJ, Ramnarine TJS, Parsch J. Sexual antagonism, temporally fluctuating selection, and variable dominance affect a regulatory polymorphism in Drosophila melanogaster. Mol Biol Evol 2021; 38:4891-4907. [PMID: 34289067 PMCID: PMC8557461 DOI: 10.1093/molbev/msab215] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Understanding how genetic variation is maintained within species is a major goal of evolutionary genetics that can shed light on the preservation of biodiversity. Here, we examined the maintenance of a regulatory single-nucleotide polymorphism (SNP) of the X-linked Drosophila melanogaster gene fezzik. The derived variant at this site is at intermediate frequency in many worldwide populations but absent in populations from the ancestral species range in sub-Saharan Africa. We collected and genotyped wild-caught individuals from a single European population biannually over a period of 5 years, which revealed an overall difference in allele frequency between the sexes and a consistent change in allele frequency across seasons in females but not in males. Modeling based on the observed allele and genotype frequencies suggested that both sexually antagonistic and temporally fluctuating selection may help maintain variation at this site. The derived variant is predicted to be female-beneficial and mostly recessive; however, there was uncertainty surrounding our dominance estimates and long-term modeling projections suggest that it is more likely to be dominant. By examining gene expression phenotypes, we found that phenotypic dominance was variable and dependent upon developmental stage and genetic background, suggesting that dominance may be variable at this locus. We further determined that fezzik expression and genotype are associated with starvation resistance in a sex-dependent manner, suggesting a potential phenotypic target of selection. By characterizing the mechanisms of selection acting on this SNP, our results improve our understanding of how selection maintains genetic and phenotypic variation in natural populations.
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Affiliation(s)
- Amanda Glaser-Schmitt
- Division of Evolutionary Biology, Faculty of Biology, Ludwig-Maximilians-University Munich, Planegg-Martinsried, Germany
| | | | - Timothy J S Ramnarine
- Division of Evolutionary Biology, Faculty of Biology, Ludwig-Maximilians-University Munich, Planegg-Martinsried, Germany
| | - John Parsch
- Division of Evolutionary Biology, Faculty of Biology, Ludwig-Maximilians-University Munich, Planegg-Martinsried, Germany
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20
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Monteiro B, Arenas M, Prata MJ, Amorim A. Evolutionary dynamics of the human pseudoautosomal regions. PLoS Genet 2021; 17:e1009532. [PMID: 33872316 PMCID: PMC8084340 DOI: 10.1371/journal.pgen.1009532] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2020] [Revised: 04/29/2021] [Accepted: 04/06/2021] [Indexed: 01/19/2023] Open
Abstract
Recombination between the X and Y human sex chromosomes is limited to the two pseudoautosomal regions (PARs) that present quite distinct evolutionary origins. Despite the crucial importance for male meiosis, genetic diversity patterns and evolutionary dynamics of these regions are poorly understood. In the present study, we analyzed and compared the genetic diversity of the PAR regions using publicly available genomic sequences encompassing both PAR1 and PAR2. Comparisons were performed through allele diversities, linkage disequilibrium status and recombination frequencies within and between X and Y chromosomes. In agreement with previous studies, we confirmed the role of PAR1 as a male-specific recombination hotspot, but also observed similar characteristic patterns of diversity in both regions although male recombination occurs at PAR2 to a much lower extent (at least one recombination event at PAR1 and in ≈1% in normal male meioses at PAR2). Furthermore, we demonstrate that both PARs harbor significantly different allele frequencies between X and Y chromosomes, which could support that recombination is not sufficient to homogenize the pseudoautosomal gene pool or is counterbalanced by other evolutionary forces. Nevertheless, the observed patterns of diversity are not entirely explainable by sexually antagonistic selection. A better understanding of such processes requires new data from intergenerational transmission studies of PARs, which would be decisive on the elucidation of PARs evolution and their role in male-driven heterosomal aneuploidies.
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Affiliation(s)
- Bruno Monteiro
- Institute of Investigation and Innovation in Health (i3S). University of Porto, Porto, Portugal
- Institute of Molecular Pathology and Immunology (IPATIMUP), University of Porto, Porto, Portugal
| | - Miguel Arenas
- Department of Biochemistry, Genetics and Immunology, University of Vigo, Vigo, Spain
- CINBIO (Biomedical Research Centre), University of Vigo, Vigo, Spain
| | - Maria João Prata
- Institute of Investigation and Innovation in Health (i3S). University of Porto, Porto, Portugal
- Institute of Molecular Pathology and Immunology (IPATIMUP), University of Porto, Porto, Portugal
- Faculty of Sciences, University of Porto, Porto, Portugal
- * E-mail:
| | - António Amorim
- Institute of Investigation and Innovation in Health (i3S). University of Porto, Porto, Portugal
- Institute of Molecular Pathology and Immunology (IPATIMUP), University of Porto, Porto, Portugal
- Faculty of Sciences, University of Porto, Porto, Portugal
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21
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Abstract
Diadromy, the predictable movements of individuals between marine and freshwater environments, is biogeographically and phylogenetically widespread across fishes. Thus, despite the high energetic and potential fitness costs involved in moving between distinct environments, diadromy appears to be an effective life history strategy. Yet, the origin and molecular mechanisms that underpin this migratory behavior are not fully understood. In this review, we aim first to summarize what is known about diadromy in fishes; this includes the phylogenetic relationship among diadromous species, a description of the main hypotheses regarding its origin, and a discussion of the presence of non-migratory populations within diadromous species. Second, we discuss how recent research based on -omics approaches (chiefly genomics, transcriptomics, and epigenomics) is beginning to provide answers to questions on the genetic bases and origin(s) of diadromy. Finally, we suggest future directions for -omics research that can help tackle questions on the evolution of diadromy.
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Affiliation(s)
- M. Lisette Delgado
- Department of Biology, Dalhousie University, Halifax, Nova Scotia, B3H 4R2, Canada
| | - Daniel E. Ruzzante
- Department of Biology, Dalhousie University, Halifax, Nova Scotia, B3H 4R2, Canada
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22
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Ruzicka F, Connallon T. Is the X chromosome a hot spot for sexually antagonistic polymorphisms? Biases in current empirical tests of classical theory. Proc Biol Sci 2020; 287:20201869. [PMID: 33081608 PMCID: PMC7661300 DOI: 10.1098/rspb.2020.1869] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2020] [Accepted: 09/21/2020] [Indexed: 12/16/2022] Open
Abstract
Females and males carry nearly identical genomes, which can constrain the evolution of sexual dimorphism and generate conditions that are favourable for maintaining sexually antagonistic (SA) polymorphisms, in which alleles beneficial for one sex are deleterious for the other. An influential theoretical prediction, by Rice (Rice 1984 Evolution38, 735-742), is that the X chromosome should be a 'hot spot' (i.e. enriched) for SA polymorphisms. While important caveats to Rice's theoretical prediction have since been highlighted (e.g. by Fry (2010) Evolution64, 1510-1516), several empirical studies appear to support it. Here, we show that current tests of Rice's theory-most of which are based on quantitative genetic measures of fitness (co)variance-are frequently biased towards detecting X-linked effects. We show that X-linked genes tend to contribute disproportionately to quantitative genetic patterns of SA fitness variation whether or not the X is enriched for SA polymorphisms. Population genomic approaches for detecting SA loci, including genome-wide association study of fitness and analyses of intersexual FST, are similarly biased towards detecting X-linked effects. In the light of our models, we critically re-evaluate empirical evidence for Rice's theory and discuss prospects for empirically testing it.
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23
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Ruzicka F, Dutoit L, Czuppon P, Jordan CY, Li X, Olito C, Runemark A, Svensson EI, Yazdi HP, Connallon T. The search for sexually antagonistic genes: Practical insights from studies of local adaptation and statistical genomics. Evol Lett 2020; 4:398-415. [PMID: 33014417 PMCID: PMC7523564 DOI: 10.1002/evl3.192] [Citation(s) in RCA: 27] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2020] [Revised: 07/13/2020] [Accepted: 07/28/2020] [Indexed: 12/16/2022] Open
Abstract
Sexually antagonistic (SA) genetic variation-in which alleles favored in one sex are disfavored in the other-is predicted to be common and has been documented in several animal and plant populations, yet we currently know little about its pervasiveness among species or its population genetic basis. Recent applications of genomics in studies of SA genetic variation have highlighted considerable methodological challenges to the identification and characterization of SA genes, raising questions about the feasibility of genomic approaches for inferring SA selection. The related fields of local adaptation and statistical genomics have previously dealt with similar challenges, and lessons from these disciplines can therefore help overcome current difficulties in applying genomics to study SA genetic variation. Here, we integrate theoretical and analytical concepts from local adaptation and statistical genomics research-including F ST and F IS statistics, genome-wide association studies, pedigree analyses, reciprocal transplant studies, and evolve-and-resequence experiments-to evaluate methods for identifying SA genes and genome-wide signals of SA genetic variation. We begin by developing theoretical models for between-sex F ST and F IS, including explicit null distributions for each statistic, and using them to critically evaluate putative multilocus signals of sex-specific selection in previously published datasets. We then highlight new statistics that address some of the limitations of F ST and F IS, along with applications of more direct approaches for characterizing SA genetic variation, which incorporate explicit fitness measurements. We finish by presenting practical guidelines for the validation and evolutionary analysis of candidate SA genes and discussing promising empirical systems for future work.
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Affiliation(s)
- Filip Ruzicka
- School of Biological SciencesMonash UniversityClaytonVIC 3800Australia
| | - Ludovic Dutoit
- Department of ZoologyUniversity of OtagoDunedin9054New Zealand
| | - Peter Czuppon
- Institute of Ecology and Environmental Sciences, UPEC, CNRS, IRD, INRASorbonne UniversitéParis75252France
- Center for Interdisciplinary Research in Biology, CNRS, Collège de FrancePSL Research UniversityParis75231France
| | - Crispin Y. Jordan
- School of Biomedical SciencesUniversity of EdinburghEdinburghEH8 9XDUnited Kingdom
| | - Xiang‐Yi Li
- Institute of BiologyUniversity of NeuchâtelNeuchatelCH‐2000Switzerland
| | - Colin Olito
- Department of BiologyLund UniversityLundSE‐22362Sweden
| | - Anna Runemark
- Department of BiologyLund UniversityLundSE‐22362Sweden
| | | | | | - Tim Connallon
- School of Biological SciencesMonash UniversityClaytonVIC 3800Australia
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24
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Carrier E, Ferchaud AL, Normandeau E, Sirois P, Bernatchez L. Estimating the contribution of Greenland Halibut ( Reinhardtius hippoglossoides) stocks to nurseries by means of genotyping-by-sequencing: Sex and time matter. Evol Appl 2020; 13:2155-2167. [PMID: 33005216 PMCID: PMC7513701 DOI: 10.1111/eva.12979] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2019] [Revised: 03/19/2020] [Accepted: 04/01/2020] [Indexed: 12/14/2022] Open
Abstract
Identification of stocks and quantification of their relative contribution to recruitment are major objectives toward improving the management and conservation of marine exploited species. Next-generation sequencing allows for thousands of genomic markers to be analyzed, which provides the resolution needed to address these questions in marine species with weakly differentiated populations. Greenland Halibut (Reinhardtius hippoglossoides) is one of the most important exploited demersal species throughout the North Atlantic, in particular in the Gulf of St. Lawrence, Canada. There, two nurseries are known, the St. Lawrence Estuary and the northern Anticosti Island, but their contribution to the renewal of stocks remains unknown. The goals of this study were (a) to document the genetic structure and (b) to estimate the contribution of the different identified breeding stocks to nurseries. We sampled 100 juveniles per nursery and 50 adults from seven sites ranging from Saguenay Fjord to offshore Newfoundland, with some sites sampled over two consecutive years in order to evaluate the temporal stability of the contribution. Our results show that after removing sex-linked markers, the Estuary/Gulf of St. Lawrence represents a single stock which is genetically distinct from the Atlantic around Newfoundland (F ST = 0.00146, p-value = .001). Population assignment showed that recruitment in both nurseries is predominantly associated with the St. Lawrence stock. However, we found that the relative contribution of both stocks to the nurseries is temporally variable with 1% contribution of the Newfoundland stock one year but up to 33% for the second year, which may be caused by year-to-year variation in larval transport into the Gulf of St. Lawrence. This study serves as a model for the identification of stocks for fisheries resources in a context where few barriers to dispersal occur, in addition to demonstrating the importance of considering sex-linked markers and temporal replicates in studies of population genomics.
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Affiliation(s)
- Emilie Carrier
- Institut de biologie intégrative et des systèmes (IBIS) Université Laval Québec City QC Canada
| | - Anne-Laure Ferchaud
- Institut de biologie intégrative et des systèmes (IBIS) Université Laval Québec City QC Canada
| | - Eric Normandeau
- Institut de biologie intégrative et des systèmes (IBIS) Université Laval Québec City QC Canada
| | - Pascal Sirois
- Département des sciences fondamentales Université du Québec à Chicoutimi Chicoutimi QC Canada
| | - Louis Bernatchez
- Institut de biologie intégrative et des systèmes (IBIS) Université Laval Québec City QC Canada
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25
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Junker J, Rick JA, McIntyre PB, Kimirei I, Sweke EA, Mosille JB, Wehrli B, Dinkel C, Mwaiko S, Seehausen O, Wagner CE. Structural genomic variation leads to genetic differentiation in Lake Tanganyika's sardines. Mol Ecol 2020; 29:3277-3298. [PMID: 32687665 DOI: 10.1111/mec.15559] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2019] [Revised: 06/27/2020] [Accepted: 06/29/2020] [Indexed: 01/03/2023]
Abstract
Identifying patterns in genetic structure and the genetic basis of ecological adaptation is a core goal of evolutionary biology and can inform the management and conservation of species that are vulnerable to population declines exacerbated by climate change. We used reduced-representation genomic sequencing methods to gain a better understanding of genetic structure among and within populations of Lake Tanganyika's two sardine species, Limnothrissa miodon and Stolothrissa tanganicae. Samples of these ecologically and economically important species were collected across the length of Lake Tanganyika, as well as from nearby Lake Kivu, where L. miodon was introduced in 1959. Our results reveal differentiation within both S. tanganicae and L. miodon that is not explained by geography. Instead, this genetic differentiation is due to the presence of large sex-specific regions in the genomes of both species, but involving different polymorphic sites in each species. Our results therefore indicate rapidly evolving XY sex determination in the two species. Additionally, we found evidence of a large chromosomal rearrangement in L. miodon, creating two homokaryotypes and one heterokaryotype. We found all karyotypes throughout Lake Tanganyika, but the frequencies vary along a north-south gradient and differ substantially in the introduced Lake Kivu population. We do not find evidence for significant isolation by distance, even over the hundreds of kilometres covered by our sampling, but we do find shallow population structure.
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Affiliation(s)
- Julian Junker
- EAWAG Swiss Federal Institute of Aquatic Science and Technology, Kastanienbaum, Switzerland.,Division of Aquatic Ecology, Institute of Ecology & Evolution, University of Bern, Bern, Switzerland
| | - Jessica A Rick
- Department of Botany and Program in Ecology, University of Wyoming, Laramie, WY, USA
| | - Peter B McIntyre
- Department of Natural Resources, Cornell University, Ithaca, NY, USA
| | - Ismael Kimirei
- Tanzania Fisheries Research Institute (TAFIRI), Dar es Salaam, Tanzania
| | - Emmanuel A Sweke
- Tanzania Fisheries Research Institute (TAFIRI), Dar es Salaam, Tanzania.,Deep Sea Fishing Authority (DSFA), Zanzibar, Tanzania
| | - Julieth B Mosille
- Tanzania Fisheries Research Institute (TAFIRI), Dar es Salaam, Tanzania
| | - Bernhard Wehrli
- EAWAG Swiss Federal Institute of Aquatic Science and Technology, Kastanienbaum, Switzerland.,Institute of Biogeochemistry and Pollutant Dynamics, ETH Zurich, Zürich, Switzerland
| | - Christian Dinkel
- EAWAG Swiss Federal Institute of Aquatic Science and Technology, Kastanienbaum, Switzerland
| | - Salome Mwaiko
- EAWAG Swiss Federal Institute of Aquatic Science and Technology, Kastanienbaum, Switzerland.,Division of Aquatic Ecology, Institute of Ecology & Evolution, University of Bern, Bern, Switzerland
| | - Ole Seehausen
- EAWAG Swiss Federal Institute of Aquatic Science and Technology, Kastanienbaum, Switzerland.,Division of Aquatic Ecology, Institute of Ecology & Evolution, University of Bern, Bern, Switzerland
| | - Catherine E Wagner
- Department of Botany and Program in Ecology, University of Wyoming, Laramie, WY, USA
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Cheng C, Kirkpatrick M. The signal of sex-specific selection in humans is not an artefact: Reply to Mank et al. Mol Ecol 2020; 29:1406-1407. [PMID: 32338415 DOI: 10.1111/mec.15420] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2020] [Revised: 03/16/2020] [Accepted: 03/19/2020] [Indexed: 02/06/2023]
Affiliation(s)
- Changde Cheng
- Department of Computational Biology, St. Jude's Children's Hospital, Memphis, TN, USA
| | - Mark Kirkpatrick
- Department of Integrative Biology, University of Texas, Austin, TX, USA
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Mank JE, Shu JJ, Wright AE. Signature of sexual conflict is actually conflict resolved. Mol Ecol 2019; 29:215-217. [PMID: 31756270 DOI: 10.1111/mec.15311] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2019] [Revised: 11/18/2019] [Accepted: 11/20/2019] [Indexed: 12/14/2022]
Abstract
There has been substantial interest of late in using population genetic methods to study sexual conflict, where an allele increases the fitness of one sex at some cost to the other (Mank, 2017). Population genomic scans for sexual conflict offer an important advance given the difficulties of identifying antagonistic alleles from more traditional methods, and could greatly increase our understanding of the extent and loci of sexual conflict. This is particularly true for studies in natural populations, for which obtaining accurate fitness measurements for each sex can be challenging. In this issue of Molecular Ecology, Bissegger, Laurentino, Roesti, and Berner (2019) present a cautionary tale about how to interpret these population genomic data.
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Affiliation(s)
- Judith E Mank
- Department of Zoology and Biodiversity Research Centre, University of British Columbia, Vancouver, BC, Canada
| | - Jacelyn J Shu
- Department of Zoology and Biodiversity Research Centre, University of British Columbia, Vancouver, BC, Canada
| | - Alison E Wright
- Department of Animal and Plant Sciences, University of Sheffield, Sheffield, UK
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