1
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Luo M, Hu J. Alternative splicing in parallel evolution and the evolutionary potential in sticklebacks. J Anim Ecol 2024. [PMID: 39056271 DOI: 10.1111/1365-2656.14157] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2023] [Accepted: 06/28/2024] [Indexed: 07/28/2024]
Abstract
Repeatability of adaptation to similar environments provides opportunity to evaluate the predictability of natural selection. While many studies have investigated gene expression differences between populations adapted to contrasting environments, the role of post-transcriptional processes such as alternative splicing has rarely been evaluated in the context of parallel adaptation. To address the aforementioned knowledge gap, we reanalysed transcriptomic data from three pairs of threespine stickleback (Gasterosteus aculeatus) ecotypes adapted to marine or freshwater environment. First, we identified genes with repeated expression or splicing divergence across ecotype pairs, and compared the genetic architecture and biological processes between parallelly expressed and parallelly spliced loci. Second, we analysed the extent to which parallel adaptation was reflected at gene expression and alternative splicing levels. Finally, we tested how the two axes of transcriptional variation differed in their potential for evolutionary change. Although both repeated differential splicing and differential expression across ecotype pairs showed tendency for parallel divergence, the degree of parallelism was lower for splicing than expression. Furthermore, parallel divergences in splicing and expression were likely to be associated with distinct cis-regulatory genetic variants and functionally unique set of genes. Finally, we found that parallelly spliced genes showed higher nucleotide diversity than parallelly expressed genes, indicating splicing is less susceptible to genetic variation erosion during parallel adaptation. Our results provide novel insight into the role of splicing in parallel adaptation, and underscore the contribution of splicing to the evolutionary potential of wild populations under environmental change.
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Affiliation(s)
- Man Luo
- Ministry of Education Key Laboratory for Biodiversity Science and Ecological Engineering, Institute of Biodiversity Science, Center for Evolutionary Biology, School of Life Sciences, Fudan University, Shanghai, China
| | - Juntao Hu
- Ministry of Education Key Laboratory for Biodiversity Science and Ecological Engineering, Institute of Biodiversity Science, Center for Evolutionary Biology, School of Life Sciences, Fudan University, Shanghai, China
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2
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Rödelsperger C. Comparative Genomics of Sex, Chromosomes, and Sex Chromosomes in Caenorhabditis elegans and Other Nematodes. Methods Mol Biol 2024; 2802:455-472. [PMID: 38819568 DOI: 10.1007/978-1-0716-3838-5_15] [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: 06/01/2024]
Abstract
The nematode phylum has evolved a remarkable diversity of reproductive modes, including the repeated emergence of asexuality and hermaphroditism across divergent clades. The species-richness and small genome size of nematodes make them ideal systems for investigating the genome-wide causes and consequences of such major transitions. The availability of functional annotations for most Caenorhabditis elegans genes further allows the linking of patterns of gene content evolution with biological processes. Such gene-centric studies were recently complemented by investigations of chromosome evolution that made use of the first chromosome-scale genome assemblies outside the Caenorhabditis genus. This review highlights recent comparative genomic studies of reproductive mode evolution addressing the hybrid origin of asexuality and the parallel gene loss following the emergence of hermaphroditism. It further summarizes ongoing efforts to characterize ancient linkage blocks called Nigon elements, which form central units of chromosome evolution. Fusions between Nigon elements have been demonstrated to impact recombination and speciation. Finally, multiple recent fusions between autosomal and the sex-linked Nigon element reveal insights into the dynamic evolution of sex chromosomes across various timescales.
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Affiliation(s)
- Christian Rödelsperger
- Department for Integrative Evolutionary Biology, Max Planck Institute for Biology, Tübingen, Germany.
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3
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Chen W, Zhou W, Li Q, Mao X. Sex differences in gene expression and alternative splicing in the Chinese horseshoe bat. PeerJ 2023; 11:e15231. [PMID: 37123006 PMCID: PMC10135408 DOI: 10.7717/peerj.15231] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2022] [Accepted: 03/24/2023] [Indexed: 05/02/2023] Open
Abstract
Sexually dimorphic traits are common in sexually reproducing organisms and can be encoded by differential gene regulation between males and females. Although alternative splicing is common mechanism in generating transcriptional diversity, its role in generating sex differences relative to differential gene expression is less clear. Here, we investigate the relative roles of differential gene expression and alternative splicing between male and female the horseshoe bat species, Rhinolophus sinicus. Horseshoe bats are an excellent model to study acoustic differences between sexes. Using RNA-seq analyses of two somatic tissues (brain and liver) from males and females of the same population, we identified 3,471 and 2,208 differentially expressed genes between the sexes (DEGs) in the brain and liver, respectively. DEGs were enriched with functional categories associated with physiological difference of the sexes (e.g.,gamete generation and energy production for reproduction in females). In addition, we also detected many differentially spliced genes between the sexes (DSGs, 2,231 and 1,027 in the brain and liver, respectively) which were mainly involved in regulation of RNA splicing and mRNA metabolic process. Interestingly, we found a significant enrichment of DEGs on the X chromosome, but not for DSGs. As for the extent of overlap between the two sets of genes, more than expected overlap of DEGs and DSGs was observed in the brain but not in the liver. This suggests that more complex tissues, such as the brain, may require the intricate and simultaneous interplay of both differential gene expression and splicing of genes to govern sex-specific functions. Overall, our results support that variation in gene expression and alternative splicing are important and complementary mechanisms governing sex differences.
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Affiliation(s)
- Wenli Chen
- School of Ecological and Environmental Sciences, East China Normal University, Shanghai, China
| | - Weiwei Zhou
- School of Ecological and Environmental Sciences, East China Normal University, Shanghai, China
| | - Qianqian Li
- School of Ecological and Environmental Sciences, East China Normal University, Shanghai, China
| | - Xiuguang Mao
- School of Ecological and Environmental Sciences, East China Normal University, Shanghai, China
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4
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Han W, Liu L, Wang J, Wei H, Li Y, Zhang L, Guo Z, Li Y, Liu T, Zeng Q, Xing Q, Shu Y, Wang T, Yang Y, Zhang M, Li R, Yu J, Pu Z, Lv J, Lian S, Hu J, Hu X, Bao Z, Bao L, Zhang L, Wang S. Ancient homomorphy of molluscan sex chromosomes sustained by reversible sex-biased genes and sex determiner translocation. Nat Ecol Evol 2022; 6:1891-1906. [PMID: 36280781 DOI: 10.1038/s41559-022-01898-6] [Citation(s) in RCA: 15] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2022] [Accepted: 09/05/2022] [Indexed: 12/15/2022]
Abstract
Contrary to classic theory prediction, sex-chromosome homomorphy is prevalent in the animal kingdom but it is unclear how ancient homomorphic sex chromosomes avoid chromosome-scale degeneration. Molluscs constitute the second largest, Precambrian-originated animal phylum and have ancient, uncharacterized homomorphic sex chromosomes. Here, we profile eight genomes of the bivalve mollusc family of Pectinidae in a phylogenetic context and show 350 million years sex-chromosome homomorphy, which is the oldest known sex-chromosome homomorphy in the animal kingdom, far exceeding the ages of well-known heteromorphic sex chromosomes such as 130-200 million years in mammals, birds and flies. The long-term undifferentiation of molluscan sex chromosomes is potentially sustained by the unexpected intertwined regulation of reversible sex-biased genes, together with the lack of sexual dimorphism and occasional sex chromosome turnover. The pleiotropic constraint of regulation of reversible sex-biased genes is widely present in ancient homomorphic sex chromosomes and might be resolved in heteromorphic sex chromosomes through gene duplication followed by subfunctionalization. The evolutionary dynamics of sex chromosomes suggest a mechanism for 'inheritance' turnover of sex-determining genes that is mediated by translocation of a sex-determining enhancer. On the basis of these findings, we propose an evolutionary model for the long-term preservation of homomorphic sex chromosomes.
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Affiliation(s)
- Wentao Han
- Sars-Fang Centre & MOE Key Laboratory of Marine Genetics and Breeding, College of Marine Life Sciences, Ocean University of China, Qingdao, China
- Laboratory for Marine Biology and Biotechnology, Qingdao National Laboratory for Marine Science and Technology, Qingdao, China
| | - Liangjie Liu
- Sars-Fang Centre & MOE Key Laboratory of Marine Genetics and Breeding, College of Marine Life Sciences, Ocean University of China, Qingdao, China
| | - Jing Wang
- Sars-Fang Centre & MOE Key Laboratory of Marine Genetics and Breeding, College of Marine Life Sciences, Ocean University of China, Qingdao, China
- Laboratory for Marine Biology and Biotechnology, Qingdao National Laboratory for Marine Science and Technology, Qingdao, China
| | - Huilan Wei
- Sars-Fang Centre & MOE Key Laboratory of Marine Genetics and Breeding, College of Marine Life Sciences, Ocean University of China, Qingdao, China
| | - Yuli Li
- Sars-Fang Centre & MOE Key Laboratory of Marine Genetics and Breeding, College of Marine Life Sciences, Ocean University of China, Qingdao, China
- Laboratory for Marine Biology and Biotechnology, Qingdao National Laboratory for Marine Science and Technology, Qingdao, China
| | - Lijing Zhang
- Sars-Fang Centre & MOE Key Laboratory of Marine Genetics and Breeding, College of Marine Life Sciences, Ocean University of China, Qingdao, China
| | - Zhenyi Guo
- Sars-Fang Centre & MOE Key Laboratory of Marine Genetics and Breeding, College of Marine Life Sciences, Ocean University of China, Qingdao, China
| | - Yajuan Li
- Sars-Fang Centre & MOE Key Laboratory of Marine Genetics and Breeding, College of Marine Life Sciences, Ocean University of China, Qingdao, China
| | - Tian Liu
- Sars-Fang Centre & MOE Key Laboratory of Marine Genetics and Breeding, College of Marine Life Sciences, Ocean University of China, Qingdao, China
| | - Qifan Zeng
- Sars-Fang Centre & MOE Key Laboratory of Marine Genetics and Breeding, College of Marine Life Sciences, Ocean University of China, Qingdao, China
- Laboratory for Marine Fisheries Science and Food Production Processes, Qingdao National Laboratory for Marine Science and Technology, Qingdao, China
- Key Laboratory of Tropical Aquatic Germplasm of Hainan Province, Sanya Oceanographic Institution, Ocean University of China, Sanya, China
| | - Qiang Xing
- Sars-Fang Centre & MOE Key Laboratory of Marine Genetics and Breeding, College of Marine Life Sciences, Ocean University of China, Qingdao, China
- Laboratory for Marine Fisheries Science and Food Production Processes, Qingdao National Laboratory for Marine Science and Technology, Qingdao, China
| | - Ya Shu
- Sars-Fang Centre & MOE Key Laboratory of Marine Genetics and Breeding, College of Marine Life Sciences, Ocean University of China, Qingdao, China
| | - Tong Wang
- Sars-Fang Centre & MOE Key Laboratory of Marine Genetics and Breeding, College of Marine Life Sciences, Ocean University of China, Qingdao, China
| | - Yaxin Yang
- Sars-Fang Centre & MOE Key Laboratory of Marine Genetics and Breeding, College of Marine Life Sciences, Ocean University of China, Qingdao, China
| | - Meiwei Zhang
- Sars-Fang Centre & MOE Key Laboratory of Marine Genetics and Breeding, College of Marine Life Sciences, Ocean University of China, Qingdao, China
| | - Ruojiao Li
- Sars-Fang Centre & MOE Key Laboratory of Marine Genetics and Breeding, College of Marine Life Sciences, Ocean University of China, Qingdao, China
| | - Jiachen Yu
- Sars-Fang Centre & MOE Key Laboratory of Marine Genetics and Breeding, College of Marine Life Sciences, Ocean University of China, Qingdao, China
| | - Zhongqi Pu
- Sars-Fang Centre & MOE Key Laboratory of Marine Genetics and Breeding, College of Marine Life Sciences, Ocean University of China, Qingdao, China
| | - Jia Lv
- Sars-Fang Centre & MOE Key Laboratory of Marine Genetics and Breeding, College of Marine Life Sciences, Ocean University of China, Qingdao, China
| | - Shanshan Lian
- Sars-Fang Centre & MOE Key Laboratory of Marine Genetics and Breeding, College of Marine Life Sciences, Ocean University of China, Qingdao, China
- Laboratory for Marine Biology and Biotechnology, Qingdao National Laboratory for Marine Science and Technology, Qingdao, China
| | - Jingjie Hu
- Sars-Fang Centre & MOE Key Laboratory of Marine Genetics and Breeding, College of Marine Life Sciences, Ocean University of China, Qingdao, China
- Key Laboratory of Tropical Aquatic Germplasm of Hainan Province, Sanya Oceanographic Institution, Ocean University of China, Sanya, China
| | - Xiaoli Hu
- Sars-Fang Centre & MOE Key Laboratory of Marine Genetics and Breeding, College of Marine Life Sciences, Ocean University of China, Qingdao, China
- Laboratory for Marine Fisheries Science and Food Production Processes, Qingdao National Laboratory for Marine Science and Technology, Qingdao, China
| | - Zhenmin Bao
- Sars-Fang Centre & MOE Key Laboratory of Marine Genetics and Breeding, College of Marine Life Sciences, Ocean University of China, Qingdao, China
- Laboratory for Marine Fisheries Science and Food Production Processes, Qingdao National Laboratory for Marine Science and Technology, Qingdao, China
- Key Laboratory of Tropical Aquatic Germplasm of Hainan Province, Sanya Oceanographic Institution, Ocean University of China, Sanya, China
| | - Lisui Bao
- Institute of Evolution & Marine Biodiversity, Ocean University of China, Qingdao, China.
| | - Lingling Zhang
- Sars-Fang Centre & MOE Key Laboratory of Marine Genetics and Breeding, College of Marine Life Sciences, Ocean University of China, Qingdao, China.
- Laboratory for Marine Biology and Biotechnology, Qingdao National Laboratory for Marine Science and Technology, Qingdao, China.
| | - Shi Wang
- Sars-Fang Centre & MOE Key Laboratory of Marine Genetics and Breeding, College of Marine Life Sciences, Ocean University of China, Qingdao, China.
- Laboratory for Marine Biology and Biotechnology, Qingdao National Laboratory for Marine Science and Technology, Qingdao, China.
- Key Laboratory of Tropical Aquatic Germplasm of Hainan Province, Sanya Oceanographic Institution, Ocean University of China, Sanya, China.
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5
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Hudson CM, Ladd SN, Leal MC, Schubert CJ, Seehausen O, Matthews B. Fit and fatty freshwater fish: contrasting polyunsaturated fatty acid phenotypes between hybridizing stickleback lineages. OIKOS 2021. [DOI: 10.1111/oik.08558] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Affiliation(s)
- Cameron M. Hudson
- Dept of Fish Ecology and Evolution, Eawag, Swiss Federal Inst. of Aquatic Science and Technology, Center of Ecology, Evolution and Biochemistry Kastanienbaum Switzerland
- Aquatic Ecology and Evolution, Inst. of Ecology and Evolution, Univ. of Bern Bern Switzerland
| | - S. Nemiah Ladd
- Dept of Surface Waters – Research and Management, Eawag, Swiss Federal Inst. of Aquatic Science and Technology, Center of Ecology, Evolution and Biochemistry Kastanienbaum Switzerland
- Ecosystem Physiology, Univ. of Freiburg Freiburg Germany
| | - Miguel C. Leal
- ECOMARE, CESAM – Center for Environmental and Marine Studies, Dept of Biology, Univ. of Aveiro, Campus Universitário de Santiago Aveiro Portugal
| | - Carsten J. Schubert
- Dept of Surface Waters – Research and Management, Eawag, Swiss Federal Inst. of Aquatic Science and Technology, Center of Ecology, Evolution and Biochemistry Kastanienbaum Switzerland
| | - Ole Seehausen
- Dept of Fish Ecology and Evolution, Eawag, Swiss Federal Inst. of Aquatic Science and Technology, Center of Ecology, Evolution and Biochemistry Kastanienbaum Switzerland
- Aquatic Ecology and Evolution, Inst. of Ecology and Evolution, Univ. of Bern Bern Switzerland
| | - Blake Matthews
- Dept of Fish Ecology and Evolution, Eawag, Swiss Federal Inst. of Aquatic Science and Technology, Center of Ecology, Evolution and Biochemistry Kastanienbaum Switzerland
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6
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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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7
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Naftaly AS, Pau S, White MA. Long-read RNA sequencing reveals widespread sex-specific alternative splicing in threespine stickleback fish. Genome Res 2021; 31:1486-1497. [PMID: 34131005 PMCID: PMC8327910 DOI: 10.1101/gr.274282.120] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2020] [Accepted: 06/15/2021] [Indexed: 01/07/2023]
Abstract
Alternate isoforms are important contributors to phenotypic diversity across eukaryotes. Although short-read RNA-sequencing has increased our understanding of isoform diversity, it is challenging to accurately detect full-length transcripts, preventing the identification of many alternate isoforms. Long-read sequencing technologies have made it possible to sequence full-length alternative transcripts, accurately characterizing alternative splicing events, alternate transcription start and end sites, and differences in UTR regions. Here, we use Pacific Biosciences (PacBio) long-read RNA-sequencing (Iso-Seq) to examine the transcriptomes of five organs in threespine stickleback fish (Gasterosteus aculeatus), a widely used genetic model species. The threespine stickleback fish has a refined genome assembly in which gene annotations are based on short-read RNA sequencing and predictions from coding sequence of other species. This suggests some of the existing annotations may be inaccurate or alternative transcripts may not be fully characterized. Using Iso-Seq we detected thousands of novel isoforms, indicating many isoforms are absent in the current Ensembl gene annotations. In addition, we refined many of the existing annotations within the genome. We noted many improperly positioned transcription start sites that were refined with long-read sequencing. The Iso-Seq-predicted transcription start sites were more accurate and verified through ATAC-seq. We also detected many alternative splicing events between sexes and across organs. We found a substantial number of genes in both somatic and gonadal samples that had sex-specific isoforms. Our study highlights the power of long-read sequencing to study the complexity of transcriptomes, greatly improving genomic resources for the threespine stickleback fish.
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Affiliation(s)
- Alice S Naftaly
- Department of Genetics, University of Georgia, Athens, Georgia 30602, USA
| | - Shana Pau
- Department of Genetics, University of Georgia, Athens, Georgia 30602, USA
- Department of Biology, University of Texas Arlington, Arlington, Texas 76019, USA
| | - Michael A White
- Department of Genetics, University of Georgia, Athens, Georgia 30602, USA
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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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Carey SB, Jenkins J, Lovell JT, Maumus F, Sreedasyam A, Payton AC, Shu S, Tiley GP, Fernandez-Pozo N, Healey A, Barry K, Chen C, Wang M, Lipzen A, Daum C, Saski CA, McBreen JC, Conrad RE, Kollar LM, Olsson S, Huttunen S, Landis JB, Burleigh JG, Wickett NJ, Johnson MG, Rensing SA, Grimwood J, Schmutz J, McDaniel SF. Gene-rich UV sex chromosomes harbor conserved regulators of sexual development. SCIENCE ADVANCES 2021; 7:7/27/eabh2488. [PMID: 34193417 PMCID: PMC8245031 DOI: 10.1126/sciadv.abh2488] [Citation(s) in RCA: 41] [Impact Index Per Article: 13.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/24/2021] [Accepted: 05/14/2021] [Indexed: 05/19/2023]
Abstract
Nonrecombining sex chromosomes, like the mammalian Y, often lose genes and accumulate transposable elements, a process termed degeneration. The correlation between suppressed recombination and degeneration is clear in animal XY systems, but the absence of recombination is confounded with other asymmetries between the X and Y. In contrast, UV sex chromosomes, like those found in bryophytes, experience symmetrical population genetic conditions. Here, we generate nearly gapless female and male chromosome-scale reference genomes of the moss Ceratodon purpureus to test for degeneration in the bryophyte UV sex chromosomes. We show that the moss sex chromosomes evolved over 300 million years ago and expanded via two chromosomal fusions. Although the sex chromosomes exhibit weaker purifying selection than autosomes, we find that suppressed recombination alone is insufficient to drive degeneration. Instead, the U and V sex chromosomes harbor thousands of broadly expressed genes, including numerous key regulators of sexual development across land plants.
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Affiliation(s)
- Sarah B Carey
- Department of Biology, University of Florida, Gainesville, FL, USA
| | - Jerry Jenkins
- Genome Sequencing Center, HudsonAlpha Institute for Biotechnology, Huntsville, AL, USA
| | - John T Lovell
- Genome Sequencing Center, HudsonAlpha Institute for Biotechnology, Huntsville, AL, USA
| | - Florian Maumus
- Université Paris-Saclay, INRAE, URGI, 78026 Versailles, France
| | - Avinash Sreedasyam
- Genome Sequencing Center, HudsonAlpha Institute for Biotechnology, Huntsville, AL, USA
| | - Adam C Payton
- Department of Biology, University of Florida, Gainesville, FL, USA
- RAPiD Genomics, Gainesville, FL, USA
| | - Shengqiang Shu
- U.S. Department of Energy Joint Genome Institute, Lawrence Berkeley National Laboratory, Berkeley, CA, USA
| | | | | | - Adam Healey
- Genome Sequencing Center, HudsonAlpha Institute for Biotechnology, Huntsville, AL, USA
| | - Kerrie Barry
- U.S. Department of Energy Joint Genome Institute, Lawrence Berkeley National Laboratory, Berkeley, CA, USA
| | - Cindy Chen
- U.S. Department of Energy Joint Genome Institute, Lawrence Berkeley National Laboratory, Berkeley, CA, USA
| | - Mei Wang
- U.S. Department of Energy Joint Genome Institute, Lawrence Berkeley National Laboratory, Berkeley, CA, USA
| | - Anna Lipzen
- U.S. Department of Energy Joint Genome Institute, Lawrence Berkeley National Laboratory, Berkeley, CA, USA
| | - Chris Daum
- U.S. Department of Energy Joint Genome Institute, Lawrence Berkeley National Laboratory, Berkeley, CA, USA
| | - Christopher A Saski
- Department of Plant and Environmental Sciences, Clemson University, Clemson, SC, USA
| | - Jordan C McBreen
- Department of Biology, University of Florida, Gainesville, FL, USA
| | - Roth E Conrad
- School of Biological Sciences, Georgia Institute of Technology, Atlanta, GA, USA
| | - Leslie M Kollar
- Department of Biology, University of Florida, Gainesville, FL, USA
| | - Sanna Olsson
- Department of Forest Ecology and Genetics, INIA-CIFOR, Madrid, Spain
| | - Sanna Huttunen
- Department of Biology and Biodiversity Unit, University of Turku, Turku, Finland
| | - Jacob B Landis
- L.H. Bailey Hortorium and Section of Plant Biology, School of Integrative Plant Science, Cornell University, Ithaca, NY, USA
| | | | - Norman J Wickett
- Negaunee Institute for Plant Conservation Science and Action, Chicago Botanic Garden, Glencoe, IL, USA
| | - Matthew G Johnson
- Department of Biological Sciences, Texas Tech University, Lubbock, TX, USA
| | - Stefan A Rensing
- Plant Cell Biology, University of Marburg, Marburg, Germany
- Center for Synthetic Microbiology (SYNMIKRO), University of Marburg, Hans-Meerwein-Straße 6, 35032 Marburg, Germany
- BIOSS Centre for Biological Signalling Studies, University of Freiburg, Schänzlestraße 18, 79104 Freiburg im Breisgau, Germany
| | - Jane Grimwood
- Genome Sequencing Center, HudsonAlpha Institute for Biotechnology, Huntsville, AL, USA
- U.S. Department of Energy Joint Genome Institute, Lawrence Berkeley National Laboratory, Berkeley, CA, USA
| | - Jeremy Schmutz
- Genome Sequencing Center, HudsonAlpha Institute for Biotechnology, Huntsville, AL, USA
- U.S. Department of Energy Joint Genome Institute, Lawrence Berkeley National Laboratory, Berkeley, CA, USA
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10
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Dor L, Shirak A, Curzon AY, Rosenfeld H, Ashkenazi IM, Nixon O, Seroussi E, Weller JI, Ron M. Preferential Mapping of Sex-Biased Differentially-Expressed Genes of Larvae to the Sex-Determining Region of Flathead Grey Mullet ( Mugil cephalus). Front Genet 2020; 11:839. [PMID: 32973865 PMCID: PMC7472742 DOI: 10.3389/fgene.2020.00839] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2020] [Accepted: 07/10/2020] [Indexed: 12/23/2022] Open
Abstract
Flathead gray mullet (Mugil cephalus) is a cosmopolitan mugilid species popular in fishery and aquaculture with an economic preference for all-female population. However, it displays neither sexual dimorphisms nor heteromorphic sex chromosomes. We have previously presented a microsatellite-based linkage map for this species locating a single sex determination region (SDR) on linkage group 9 (LG9) with evidence for XX/XY sex determination (SD) mechanism. In this work, we refine the critical SDR on LG9, and propose positional- and functional- candidate genes for SD. To elucidate the genetic mechanism of SD, we assembled and compared male and female genomic sequences of 19 syntenic genes within the putative SDR on mullet's LG9, based on orthology to tilapia's LG8 (tLG8) physical map. A total of 25 sequence-based markers in 12 genes were developed. For all markers, we observed association with sex in at least one of the two analyzed M. cephalus full-sib families, but not in the wild-type population. Recombination events were inferred within families thus setting the SDR boundaries to a region orthologous to ∼0.9 Mbp with 27 genes on tLG8. As the sexual phenotype is evident only in adults, larvae were assigned into two putative sex-groups according to their paternal haplotypes, following a model of XY/XX SD-system. A total of 107 sex-biased differentially expressed genes in larvae were observed, of which 51 were mapped to tLG8 (48% enrichment), as compared to 5% in random control. Furthermore, 23 of the 107 genes displayed sex-specific expression; and 22 of these genes were positioned to tLG8, indicating 96% enrichment. Of the 27 SDR genes, BCCIP, DHX32A, DOCK1, and FSHR (GTH-RI) are suggested as positional and functional gene candidates for SD.
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Affiliation(s)
- Lior Dor
- Institute of Animal Science, Agricultural Research Organization, Bet Dagan, Israel
- Robert H. Smith Faculty of Agriculture, Food and Environment, The Hebrew University of Jerusalem, Rehovot, Israel
| | - Andrey Shirak
- Robert H. Smith Faculty of Agriculture, Food and Environment, The Hebrew University of Jerusalem, Rehovot, Israel
| | - Arie Y. Curzon
- Institute of Animal Science, Agricultural Research Organization, Bet Dagan, Israel
- Robert H. Smith Faculty of Agriculture, Food and Environment, The Hebrew University of Jerusalem, Rehovot, Israel
| | - Hana Rosenfeld
- National Center for Mariculture, Israel Oceanographic and Limnological Research, Eilat, Israel
| | - Iris M. Ashkenazi
- National Center for Mariculture, Israel Oceanographic and Limnological Research, Eilat, Israel
| | - Oriya Nixon
- National Center for Mariculture, Israel Oceanographic and Limnological Research, Eilat, Israel
| | - Eyal Seroussi
- Institute of Animal Science, Agricultural Research Organization, Bet Dagan, Israel
| | - Joel I. Weller
- Institute of Animal Science, Agricultural Research Organization, Bet Dagan, Israel
| | - Micha Ron
- Institute of Animal Science, Agricultural Research Organization, Bet Dagan, Israel
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11
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Kitano J, Kakioka R, Ishikawa A, Toyoda A, Kusakabe M. Differences in the contributions of sex linkage and androgen regulation to sex-biased gene expression in juvenile and adult sticklebacks. J Evol Biol 2020; 33:1129-1138. [PMID: 32533720 DOI: 10.1111/jeb.13662] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2020] [Revised: 05/30/2020] [Accepted: 06/02/2020] [Indexed: 11/29/2022]
Abstract
Different evolutionary interests between males and females can lead to the evolution of sexual dimorphism. However, intersex genetic correlations due to the shared genome can constrain the evolution of sexual dimorphism, resulting in intra-locus sexual conflict. One of the mechanisms resolving this conflict is sex linkage, which allows males and females to carry different alleles on sex chromosomes. Another is a regulatory mutation causing sex-biased gene expression, which is often mediated by gonadal steroids in vertebrates. How do these two mechanisms differ in the contributions to the resolution of intra-locus sexual conflict? The magnitude of sexual conflict often varies between the juvenile and adult stages. Because gonadal steroids change in titre during development, we hypothesized that gonadal steroids play a role in sexual dimorphism expression only at certain developmental stages, whereas sex linkage is more important for sexual dimorphism expressed throughout life. Our brain transcriptome analysis of juvenile and adult threespine sticklebacks showed that the majority of genes that were sex-biased in both stages were sex-linked. The relative contribution of androgen-dependent regulation to the sex-biased transcriptome increased and that of sex linkage declined in adults compared to juveniles. The magnitude of the sex differences was greater in sex-linked genes than androgen-responsive genes, suggesting that sex linkage is more effective than androgen regulation in the production of large sex differences in gene expression. Overall, our data are consistent with the hypothesis that sex linkage is effective in resolving sexual conflict throughout life, whereas androgen-dependent regulation can contribute to temporary resolution of sexual conflict.
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Affiliation(s)
- Jun Kitano
- Ecological Genetics Laboratory, National Institute of Genetics, Mishima, Shizuoka, Japan
| | - Ryo Kakioka
- Ecological Genetics Laboratory, National Institute of Genetics, Mishima, Shizuoka, Japan
| | - Asano Ishikawa
- Ecological Genetics Laboratory, National Institute of Genetics, Mishima, Shizuoka, Japan
| | - Atsushi Toyoda
- Comparative Genomics Laboratory, National Institute of Genetics, Mishima, Shizuoka, Japan
| | - Makoto Kusakabe
- Department of Biological Sciences, Faculty of Science, Shizuoka University, Surugaku, Shizuoka, Japan
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12
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Carey SB, Jenkins J, Lovell JT, Maumus F, Sreedasyam A, Payton AC, Shu S, Tiley GP, Fernandez-pozo N, Barry K, Chen C, Wang M, Lipzen A, Daum C, Saski CA, Mcbreen JC, Conrad RE, Kollar LM, Olsson S, Huttunen S, Landis JB, Burleigh JG, Wickett NJ, Johnson MG, Rensing SA, Grimwood J, Schmutz J, Mcdaniel SF. The Ceratodon purpureus genome uncovers structurally complex, gene rich sex chromosomes.. [PMID: 0 DOI: 10.1101/2020.07.03.163634] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/06/2023]
Abstract
AbstractNon-recombining sex chromosomes, like the mammalian Y, often lose genes and accumulate transposable elements, a process termed degeneration1,2. The correlation between suppressed recombination and degeneration is clear in animal XY systems1,2, but the absence of recombination is confounded with other asymmetries between the X and Y. In contrast, UV sex chromosomes, like those found in bryophytes, experience symmetrical population genetic conditions3,4. Here we test for degeneration in the bryophyte UV sex chromosome system through genomic comparisons with new female and male chromosome-scale reference genomes of the moss Ceratodon purpureus. We show that the moss sex chromosomes evolved over 300 million years ago and expanded via two chromosomal fusions. Although the sex chromosomes show signs of weaker purifying selection than autosomes, we find suppressed recombination alone is insufficient to drive gene loss on sex-specific chromosomes. Instead, the U and V sex chromosomes harbor thousands of broadly-expressed genes, including numerous key regulators of sexual development across land plants.
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13
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Furman BLS, Metzger DCH, Darolti I, Wright AE, Sandkam BA, Almeida P, Shu JJ, Mank JE. Sex Chromosome Evolution: So Many Exceptions to the Rules. Genome Biol Evol 2020; 12:750-763. [PMID: 32315410 PMCID: PMC7268786 DOI: 10.1093/gbe/evaa081] [Citation(s) in RCA: 98] [Impact Index Per Article: 24.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 04/14/2020] [Indexed: 01/10/2023] Open
Abstract
Genomic analysis of many nonmodel species has uncovered an incredible diversity of sex chromosome systems, making it possible to empirically test the rich body of evolutionary theory that describes each stage of sex chromosome evolution. Classic theory predicts that sex chromosomes originate from a pair of homologous autosomes and recombination between them is suppressed via inversions to resolve sexual conflict. The resulting degradation of the Y chromosome gene content creates the need for dosage compensation in the heterogametic sex. Sex chromosome theory also implies a linear process, starting from sex chromosome origin and progressing to heteromorphism. Despite many convergent genomic patterns exhibited by independently evolved sex chromosome systems, and many case studies supporting these theoretical predictions, emerging data provide numerous interesting exceptions to these long-standing theories, and suggest that the remarkable diversity of sex chromosomes is matched by a similar diversity in their evolution. For example, it is clear that sex chromosome pairs are not always derived from homologous autosomes. In addition, both the cause and the mechanism of recombination suppression between sex chromosome pairs remain unclear, and it may be that the spread of recombination suppression is a more gradual process than previously thought. It is also clear that dosage compensation can be achieved in many ways, and displays a range of efficacy in different systems. Finally, the remarkable turnover of sex chromosomes in many systems, as well as variation in the rate of sex chromosome divergence, suggest that assumptions about the inevitable linearity of sex chromosome evolution are not always empirically supported, and the drivers of the birth-death cycle of sex chromosome evolution remain to be elucidated. Here, we concentrate on how the diversity in sex chromosomes across taxa highlights an equal diversity in each stage of sex chromosome evolution.
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Affiliation(s)
- Benjamin L S Furman
- Beaty Biodiversity Research Centre, University of British Columbia, Vancouver, British Columbia, Canada
- Department of Zoology, University of British Columbia, Vancouver, British Columbia, Canada
| | - David C H Metzger
- Beaty Biodiversity Research Centre, University of British Columbia, Vancouver, British Columbia, Canada
- Department of Zoology, University of British Columbia, Vancouver, British Columbia, Canada
| | - Iulia Darolti
- Beaty Biodiversity Research Centre, University of British Columbia, Vancouver, British Columbia, Canada
- Department of Zoology, University of British Columbia, Vancouver, British Columbia, Canada
| | - Alison E Wright
- Department of Animal and Plant Sciences, University of Sheffield, United Kingdom
| | - Benjamin A Sandkam
- Beaty Biodiversity Research Centre, University of British Columbia, Vancouver, British Columbia, Canada
- Department of Zoology, University of British Columbia, Vancouver, British Columbia, Canada
| | - Pedro Almeida
- Department of Genetics, Evolution and Environment, University College London, United Kingdom
| | - Jacelyn J Shu
- Beaty Biodiversity Research Centre, University of British Columbia, Vancouver, British Columbia, Canada
- Department of Zoology, University of British Columbia, Vancouver, British Columbia, Canada
| | - Judith E Mank
- Beaty Biodiversity Research Centre, University of British Columbia, Vancouver, British Columbia, Canada
- Department of Zoology, University of British Columbia, Vancouver, British Columbia, Canada
- Department of Genetics, Evolution and Environment, University College London, United Kingdom
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14
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Lindsay WR, Andersson S, Bererhi B, Höglund J, Johnsen A, Kvarnemo C, Leder EH, Lifjeld JT, Ninnes CE, Olsson M, Parker GA, Pizzari T, Qvarnström A, Safran RJ, Svensson O, Edwards SV. Endless forms of sexual selection. PeerJ 2019; 7:e7988. [PMID: 31720113 PMCID: PMC6839514 DOI: 10.7717/peerj.7988] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2019] [Accepted: 10/04/2019] [Indexed: 12/11/2022] Open
Abstract
In recent years, the field of sexual selection has exploded, with advances in theoretical and empirical research complementing each other in exciting ways. This perspective piece is the product of a "stock-taking" workshop on sexual selection and sexual conflict. Our aim is to identify and deliberate on outstanding questions and to stimulate discussion rather than provide a comprehensive overview of the entire field. These questions are organized into four thematic sections we deem essential to the field. First we focus on the evolution of mate choice and mating systems. Variation in mate quality can generate both competition and choice in the opposite sex, with implications for the evolution of mating systems. Limitations on mate choice may dictate the importance of direct vs. indirect benefits in mating decisions and consequently, mating systems, especially with regard to polyandry. Second, we focus on how sender and receiver mechanisms shape signal design. Mediation of honest signal content likely depends on integration of temporally variable social and physiological costs that are challenging to measure. We view the neuroethology of sensory and cognitive receiver biases as the main key to signal form and the 'aesthetic sense' proposed by Darwin. Since a receiver bias is sufficient to both initiate and drive ornament or armament exaggeration, without a genetically correlated or even coevolving receiver, this may be the appropriate 'null model' of sexual selection. Thirdly, we focus on the genetic architecture of sexually selected traits. Despite advances in modern molecular techniques, the number and identity of genes underlying performance, display and secondary sexual traits remains largely unknown. In-depth investigations into the genetic basis of sexual dimorphism in the context of long-term field studies will reveal constraints and trajectories of sexually selected trait evolution. Finally, we focus on sexual selection and conflict as drivers of speciation. Population divergence and speciation are often influenced by an interplay between sexual and natural selection. The extent to which sexual selection promotes or counteracts population divergence may vary depending on the genetic architecture of traits as well as the covariance between mating competition and local adaptation. Additionally, post-copulatory processes, such as selection against heterospecific sperm, may influence the importance of sexual selection in speciation. We propose that efforts to resolve these four themes can catalyze conceptual progress in the field of sexual selection, and we offer potential avenues of research to advance this progress.
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Affiliation(s)
- Willow R. Lindsay
- Department of Biological and Environmental Sciences, University of Gothenburg, Göteborg, Sweden
| | - Staffan Andersson
- Department of Biological and Environmental Sciences, University of Gothenburg, Göteborg, Sweden
| | - Badreddine Bererhi
- Department of Biological and Environmental Sciences, University of Gothenburg, Göteborg, Sweden
| | - Jacob Höglund
- Department of Ecology and Genetics, Uppsala University, Uppsala, Sweden
| | - Arild Johnsen
- Natural History Museum, University of Oslo, Oslo, Norway
| | - Charlotta Kvarnemo
- Department of Biological and Environmental Sciences, University of Gothenburg, Göteborg, Sweden
| | - Erica H. Leder
- Natural History Museum, University of Oslo, Oslo, Norway
| | - Jan T. Lifjeld
- Natural History Museum, University of Oslo, Oslo, Norway
| | - Calum E. Ninnes
- Department of Biological and Environmental Sciences, University of Gothenburg, Göteborg, Sweden
- Department of Entomology and Nematology, University of Florida, Gainesville, FL, United States of America
| | - Mats Olsson
- Department of Biological and Environmental Sciences, University of Gothenburg, Göteborg, Sweden
| | - Geoff A. Parker
- Institute of Integrative Biology, University of Liverpool, Liverpool, United Kingdom
| | - Tommaso Pizzari
- Department of Zoology, Edward Grey Institute, University of Oxford, Oxford, United Kingdom
| | - Anna Qvarnström
- Department of Ecology and Genetics, Uppsala University, Uppsala, Sweden
| | - Rebecca J. Safran
- Department of Ecology and Evolutionary Biology, University of Colorado, Boulder, CO, United States of America
| | - Ola Svensson
- School of Natural Sciences, Technology and Environmental Studies, Södertörn University, Huddinge, Sweden
| | - Scott V. Edwards
- Department of Organismic and Evolutionary Biology and Museum of Comparative Zoology, Harvard University, Cambridge, MA, United States of America
- Gothenburg Centre for Advanced Studies in Science and Technology, Chalmers University of Technology, Göteborg, Sweden
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15
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Wan ZY, Lin G, Yue G. Genes for sexual body size dimorphism in hybrid tilapia (Oreochromis sp. x Oreochromis mossambicus). AQUACULTURE AND FISHERIES 2019. [DOI: 10.1016/j.aaf.2019.05.003] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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16
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Extreme heterogeneity in sex chromosome differentiation and dosage compensation in livebearers. Proc Natl Acad Sci U S A 2019; 116:19031-19036. [PMID: 31484763 PMCID: PMC6754558 DOI: 10.1073/pnas.1905298116] [Citation(s) in RCA: 46] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Once recombination is halted between the X and Y chromosomes, sex chromosomes begin to differentiate and transition to heteromorphism. While there is a remarkable variation across clades in the degree of sex chromosome divergence, far less is known about the variation in sex chromosome differentiation within clades. Here, we combined whole-genome and transcriptome sequencing data to characterize the structure and conservation of sex chromosome systems across Poeciliidae, the livebearing clade that includes guppies. We found that the Poecilia reticulata XY system is much older than previously thought, being shared not only with its sister species, Poecilia wingei, but also with Poecilia picta, which diverged roughly 20 million years ago. Despite the shared ancestry, we uncovered an extreme heterogeneity across these species in the proportion of the sex chromosome with suppressed recombination, and the degree of Y chromosome decay. The sex chromosomes in P. reticulata and P. wingei are largely homomorphic, with recombination in the former persisting over a substantial fraction. However, the sex chromosomes in P. picta are completely nonrecombining and strikingly heteromorphic. Remarkably, the profound degradation of the ancestral Y chromosome in P. picta is counterbalanced by the evolution of functional chromosome-wide dosage compensation in this species, which has not been previously observed in teleost fish. Our results offer important insight into the initial stages of sex chromosome evolution and dosage compensation.
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17
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Veltsos P, Ridout KE, Toups MA, González-Martínez SC, Muyle A, Emery O, Rastas P, Hudzieczek V, Hobza R, Vyskot B, Marais GAB, Filatov DA, Pannell JR. Early Sex-Chromosome Evolution in the Diploid Dioecious Plant Mercurialis annua. Genetics 2019; 212:815-835. [PMID: 31113811 PMCID: PMC6614902 DOI: 10.1534/genetics.119.302045] [Citation(s) in RCA: 39] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2019] [Accepted: 05/13/2019] [Indexed: 12/30/2022] Open
Abstract
Suppressed recombination allows divergence between homologous sex chromosomes and the functionality of their genes. Here, we reveal patterns of the earliest stages of sex-chromosome evolution in the diploid dioecious herb Mercurialis annua on the basis of cytological analysis, de novo genome assembly and annotation, genetic mapping, exome resequencing of natural populations, and transcriptome analysis. The genome assembly contained 34,105 expressed genes, of which 10,076 were assigned to linkage groups. Genetic mapping and exome resequencing of individuals across the species range both identified the largest linkage group, LG1, as the sex chromosome. Although the sex chromosomes of M. annua are karyotypically homomorphic, we estimate that about one-third of the Y chromosome, containing 568 transcripts and spanning 22.3 cM in the corresponding female map, has ceased recombining. Nevertheless, we found limited evidence for Y-chromosome degeneration in terms of gene loss and pseudogenization, and most X- and Y-linked genes appear to have diverged in the period subsequent to speciation between M. annua and its sister species M. huetii, which shares the same sex-determining region. Taken together, our results suggest that the M. annua Y chromosome has at least two evolutionary strata: a small old stratum shared with M. huetii, and a more recent larger stratum that is probably unique to M. annua and that stopped recombining ∼1 MYA. Patterns of gene expression within the nonrecombining region are consistent with the idea that sexually antagonistic selection may have played a role in favoring suppressed recombination.
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Affiliation(s)
- Paris Veltsos
- Department of Biology, Indiana University, Bloomington, IN 47405
- Department of Ecology and Evolution, University of Lausanne, CH-1015, Switzerland
| | - Kate E Ridout
- Department of Ecology and Evolution, University of Lausanne, CH-1015, Switzerland
- Department of Plant Sciences, University of Oxford, OX1 3RB, United Kingdom
- Department of Oncology, John Radcliffe Hospital, Oxford OX3 9DU, United Kingdom
| | - Melissa A Toups
- Department of Ecology and Evolution, University of Lausanne, CH-1015, Switzerland
- Department of Integrative Biology, University of Texas, Austin, 78712 Texas
| | | | - Aline Muyle
- Laboratoire Biométrie et Biologie Évolutive (UMR 5558), CNRS/Université Lyon 1, 69100 Villeurbanne, France
| | - Olivier Emery
- Department of Ecology and Evolution, University of Lausanne, CH-1015, Switzerland
| | - Pasi Rastas
- University of Helsinki, Institute of Biotechnology, 00014, Finland
| | - Vojtech Hudzieczek
- Department of Plant Developmental Genetics, Institute of Biophysics, Academy of Sciences of the Czech Republic, 61200 Brno, Czech Republic
| | - Roman Hobza
- Department of Plant Developmental Genetics, Institute of Biophysics, Academy of Sciences of the Czech Republic, 61200 Brno, Czech Republic
| | - Boris Vyskot
- Department of Plant Developmental Genetics, Institute of Biophysics, Academy of Sciences of the Czech Republic, 61200 Brno, Czech Republic
| | | | - Dmitry A Filatov
- Department of Plant Sciences, University of Oxford, OX1 3RB, United Kingdom
| | - John R Pannell
- Department of Ecology and Evolution, University of Lausanne, CH-1015, Switzerland
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18
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Metzger DCH, Schulte PM. The DNA Methylation Landscape of Stickleback Reveals Patterns of Sex Chromosome Evolution and Effects of Environmental Salinity. Genome Biol Evol 2018; 10:775-785. [PMID: 29420714 PMCID: PMC5841383 DOI: 10.1093/gbe/evy034] [Citation(s) in RCA: 36] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 02/05/2018] [Indexed: 12/12/2022] Open
Abstract
Epigenetic mechanisms such as DNA methylation are a key component of dosage compensation on sex chromosomes and have been proposed as an important source of phenotypic variation influencing plasticity and adaptive evolutionary processes, yet little is known about the role of DNA methylation in an ecological or evolutionary context in vertebrates. The threespine stickleback (Gasterosteus aculeatus) is an ecological and evolutionary model system that has been used to study mechanisms involved in the evolution of adaptive phenotypes in novel environments as well as the evolution heteromorphic sex chromosomes and dosage compensation in vertebrates. Using whole genome bisulfite sequencing, we compared genome-wide DNA methylation patterns between threespine stickleback males and females and between stickleback reared at different environmental salinities. Apparent hypermethylation of the younger evolutionary stratum of the stickleback X chromosome in females relative to males suggests a potential role of DNA methylation in the evolution of heteromorphic sex chromosomes. We also demonstrate that rearing salinity has genome-wide effects on DNA methylation levels, which has the potential to lead to the accumulation of epigenetic variation between natural populations in different environments.
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Affiliation(s)
- David C H Metzger
- Department of Zoology, University of British Columbia, Vancouver, BC, Canada
| | - Patricia M Schulte
- Department of Zoology, University of British Columbia, Vancouver, BC, Canada
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19
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Sigeman H, Ponnikas S, Videvall E, Zhang H, Chauhan P, Naurin S, Hansson B. Insights into Avian Incomplete Dosage Compensation: Sex-Biased Gene Expression Coevolves with Sex Chromosome Degeneration in the Common Whitethroat. Genes (Basel) 2018; 9:genes9080373. [PMID: 30049999 PMCID: PMC6116046 DOI: 10.3390/genes9080373] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2018] [Revised: 07/19/2018] [Accepted: 07/23/2018] [Indexed: 02/02/2023] Open
Abstract
Non-recombining sex chromosomes (Y and W) accumulate deleterious mutations and degenerate. This poses a problem for the heterogametic sex (XY males; ZW females) because a single functional gene copy often implies less gene expression and a potential imbalance of crucial expression networks. Mammals counteract this by dosage compensation, resulting in equal sex chromosome expression in males and females, whereas birds show incomplete dosage compensation with significantly lower expression in females (ZW). Here, we study the evolution of Z and W sequence divergence and sex-specific gene expression in the common whitethroat (Sylvia communis), a species within the Sylvioidea clade where a neo-sex chromosome has been formed by a fusion between an autosome and the ancestral sex chromosome. In line with data from other birds, females had lower expression than males at the majority of sex-linked genes. Results from the neo-sex chromosome region showed that W gametologs have diverged functionally to a higher extent than their Z counterparts, and that the female-to-male expression ratio correlated negatively with the degree of functional divergence of these gametologs. We find it most likely that sex-linked genes are being suppressed in females as a response to W chromosome degradation, rather than that these genes experience relaxed selection, and thus diverge more, by having low female expression. Overall, our data of this unique avian neo-sex chromosome system suggest that incomplete dosage compensation evolves, at least partly, through gradual accumulation of deleterious mutations at the W chromosome and declining female gene expression.
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Affiliation(s)
- Hanna Sigeman
- Department of Biology, Lund University, Ecology Building, 223 62 Lund, Sweden.
| | - Suvi Ponnikas
- Department of Biology, Lund University, Ecology Building, 223 62 Lund, Sweden.
| | - Elin Videvall
- Department of Biology, Lund University, Ecology Building, 223 62 Lund, Sweden.
| | - Hongkai Zhang
- Department of Biology, Lund University, Ecology Building, 223 62 Lund, Sweden.
| | - Pallavi Chauhan
- Department of Biology, Lund University, Ecology Building, 223 62 Lund, Sweden.
| | - Sara Naurin
- Department of Biology, Lund University, Ecology Building, 223 62 Lund, Sweden.
| | - Bengt Hansson
- Department of Biology, Lund University, Ecology Building, 223 62 Lund, Sweden.
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20
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Ma WJ, Veltsos P, Toups MA, Rodrigues N, Sermier R, Jeffries DL, Perrin N. Tissue Specificity and Dynamics of Sex-Biased Gene Expression in a Common Frog Population with Differentiated, Yet Homomorphic, Sex Chromosomes. Genes (Basel) 2018; 9:E294. [PMID: 29895802 PMCID: PMC6027210 DOI: 10.3390/genes9060294] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2018] [Revised: 06/04/2018] [Accepted: 06/11/2018] [Indexed: 02/06/2023] Open
Abstract
Sex-biased genes are central to the study of sexual selection, sexual antagonism, and sex chromosome evolution. We describe a comprehensive de novo assembled transcriptome in the common frog Rana temporaria based on five developmental stages and three adult tissues from both sexes, obtained from a population with karyotypically homomorphic but genetically differentiated sex chromosomes. This allows the study of sex-biased gene expression throughout development, and its effect on the rate of gene evolution while accounting for pleiotropic expression, which is known to negatively correlate with the evolutionary rate. Overall, sex-biased genes had little overlap among developmental stages and adult tissues. Late developmental stages and gonad tissues had the highest numbers of stage- or tissue-specific genes. We find that pleiotropic gene expression is a better predictor than sex bias for the evolutionary rate of genes, though it often interacts with sex bias. Although genetically differentiated, the sex chromosomes were not enriched in sex-biased genes, possibly due to a very recent arrest of XY recombination. These results extend our understanding of the developmental dynamics, tissue specificity, and genomic localization of sex-biased genes.
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Affiliation(s)
- Wen-Juan Ma
- Department of Ecology and Evolution, University of Lausanne, CH 1015 Lausanne, Switzerland.
| | - Paris Veltsos
- Department of Ecology and Evolution, University of Lausanne, CH 1015 Lausanne, Switzerland.
- Department of Biology, Indiana University, Jordan Hall, 1001 East Third Street, Bloomington, IN 47405, USA.
| | - Melissa A Toups
- Department of Ecology and Evolution, University of Lausanne, CH 1015 Lausanne, Switzerland.
- Institute of Science and Technology Austria, Am Campus 1, 3400 Klosterneuburg, Austria.
| | - Nicolas Rodrigues
- Department of Ecology and Evolution, University of Lausanne, CH 1015 Lausanne, Switzerland.
| | - Roberto Sermier
- Department of Ecology and Evolution, University of Lausanne, CH 1015 Lausanne, Switzerland.
| | - Daniel L Jeffries
- Department of Ecology and Evolution, University of Lausanne, CH 1015 Lausanne, Switzerland.
| | - Nicolas Perrin
- Department of Ecology and Evolution, University of Lausanne, CH 1015 Lausanne, Switzerland.
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21
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Evidence of sex-bias in gene expression in the brain transcriptome of two populations of rainbow trout (Oncorhynchus mykiss) with divergent life histories. PLoS One 2018; 13:e0193009. [PMID: 29447294 PMCID: PMC5814004 DOI: 10.1371/journal.pone.0193009] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2017] [Accepted: 02/03/2018] [Indexed: 11/19/2022] Open
Abstract
Sex-bias in gene expression is a mechanism that can generate phenotypic variance between the sexes, however, relatively little is known about how patterns of sex-bias vary during development, and how variable sex-bias is between different populations. To that end, we measured sex-bias in gene expression in the brain transcriptome of rainbow trout (Oncorhynchus mykiss) during the first two years of development. Our sampling included from the fry stage through to when O. mykiss either migrate to the ocean or remain resident and undergo sexual maturation. Samples came from two F1 lines: One from migratory steelhead trout and one from resident rainbow trout. All samples were reared in a common garden environment and RNA sequencing (RNA-seq) was used to estimate patterns of gene expression. A total of 1,716 (4.6% of total) genes showed evidence of sex-bias in gene expression in at least one time point. The majority (96.7%) of sex-biased genes were differentially expressed during the second year of development, indicating that patterns of sex-bias in expression are tied to key developmental events, such as migration and sexual maturation. Mapping of differentially expressed genes to the O. mykiss genome revealed that the X chromosome is enriched for female upregulated genes, and this may indicate a lack of dosage compensation in rainbow trout. There were many more sex-biased genes in the migratory line than the resident line suggesting differences in patterns of gene expression in the brain between populations subjected to different forces of selection. Overall, our results suggest that there is considerable variation in the extent and identity of genes exhibiting sex-bias during the first two years of life. These differentially expressed genes may be connected to developmental differences between the sexes, and/or between adopting a resident or migratory life history.
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Beal AP, Martin FD, Hale MC. Using RNA-seq to determine patterns of sex-bias in gene expression in the brain of the sex-role reversed Gulf Pipefish (Syngnathus scovelli). Mar Genomics 2018; 37:120-127. [DOI: 10.1016/j.margen.2017.09.005] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2017] [Revised: 09/15/2017] [Accepted: 09/15/2017] [Indexed: 10/18/2022]
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Small CM, Milligan-Myhre K, Bassham S, Guillemin K, Cresko WA. Host Genotype and Microbiota Contribute Asymmetrically to Transcriptional Variation in the Threespine Stickleback Gut. Genome Biol Evol 2017; 9:504-520. [PMID: 28391321 PMCID: PMC5381569 DOI: 10.1093/gbe/evx014] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 02/26/2017] [Indexed: 02/07/2023] Open
Abstract
Recent studies of interactions between hosts and their resident microbes have revealed important ecological and evolutionary consequences that emerge from these complex interspecies relationships, including diseases that occur when the interactions go awry. Given the preponderance of these interactions, we hypothesized that effects of the microbiota on gene expression in the developing gut—an important aspect of host biology—would be pervasive, and that these effects would be both comparable in magnitude to and contingent on effects of the host genetic background. To evaluate the effects of the microbiota, host genotype, and their interaction on gene expression in the gut of a genetically diverse, gnotobiotic host model, the threespine stickleback (Gasterosteus aculeatus), we compared RNA-seq data among 84 larval fish. Surprisingly, we found that stickleback population and family differences explained substantially more gene expression variation than the presence of microbes. Expression levels of 72 genes, however, were affected by our microbiota treatment. These genes, including many associated with innate immunity, comprise a tractable subset of host genetic factors for precise, systems-level study of host–microbe interactions in the future. Importantly, our data also suggest subtle signatures of a statistical interaction between host genotype and the microbiota on expression patterns of genetic pathways associated with innate immunity, coagulation and complement cascades, focal adhesion, cancer, and peroxisomes. These genotype-by-environment interactions may prove to be important leads to the understanding of host genetic mechanisms commonly at the root of sometimes complex molecular relationships between hosts and their resident microbes.
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Affiliation(s)
- Clayton M Small
- Institute of Ecology and Evolution, University of Oregon, Eugene, OR
| | | | - Susan Bassham
- Institute of Ecology and Evolution, University of Oregon, Eugene, OR
| | - Karen Guillemin
- Institute of Molecular Biology, University of Oregon, Eugene, OR
| | - William A Cresko
- Institute of Ecology and Evolution, University of Oregon, Eugene, OR
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24
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Chandler CH. When and why does sex chromosome dosage compensation evolve? Ann N Y Acad Sci 2017; 1389:37-51. [DOI: 10.1111/nyas.13307] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2016] [Revised: 11/21/2016] [Accepted: 12/01/2016] [Indexed: 01/07/2023]
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25
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Yang L, Zhang Z, He S. Both Male-Biased and Female-Biased Genes Evolve Faster in Fish Genomes. Genome Biol Evol 2016; 8:3433-3445. [PMID: 27742722 PMCID: PMC5203780 DOI: 10.1093/gbe/evw239] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Males and females often display extensive phenotypic differences, and many of these sexual dimorphisms are thought to result from differences between males and females in expression of genes present in both sexes. Sex-biased genes have been shown to exhibit accelerated rates of evolution in a wide array of species, however the cause of this remains enigmatic. In this study, we investigate the extent and evolutionary dynamics of sex-biased gene expression in zebrafish. Our results indicate that both male-biased genes and female-biased genes exhibit accelerated evolution at the protein level. In order to differentiate between adaptive and nonadaptive causes, we tested for codon usage bias and signatures of different selective regimes in our sequence data. Our results show that both male- and female-biased genes show signatures consistent with adaptive evolution. In order to test the generality of our findings across fish, we also analyzed publicly available data on sticklebacks, and found results consistent with our findings in zebrafish.
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Affiliation(s)
- Liandong Yang
- The Key Laboratory of Aquatic Biodiversity and Conservation of Chinese Academy of Sciences, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, People's Republic of China
| | - Zhaolei Zhang
- Department of Molecular Genetics, University of Toronto, Toronto, ON, Canada.,Donnelly Centre for Cellular and Biomolecular Research, University of Toronto, Toronto, ON, Canada
| | - Shunping He
- The Key Laboratory of Aquatic Biodiversity and Conservation of Chinese Academy of Sciences, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, People's Republic of China
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Metzger DCH, Schulte PM. Maternal stress has divergent effects on gene expression patterns in the brains of male and female threespine stickleback. Proc Biol Sci 2016; 283:rspb.2016.1734. [PMID: 27683372 DOI: 10.1098/rspb.2016.1734] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2016] [Accepted: 09/05/2016] [Indexed: 11/12/2022] Open
Abstract
Maternal stress can have long-term effects on neurodevelopment that can influence offspring performance and population evolutionary trajectories. To examine the mechanistic basis for these neurodevelopmental effects of maternal stress, we used RNA-seq to assess differential gene expression across the brain transcriptome of adult male and female threespine stickleback (Gasterosteus aculeatus) from stressed and unstressed mothers. We identified sexually divergent effects of maternal stress on the brain transcriptome. In males, genes that were upregulated by maternal stress were enriched for processes involved in synaptic function and organization and steroid hormone-mediated signalling pathways, whereas in females genes that were upregulated by maternal stress were enriched for processes involved in protein translation and metabolic functions. The expression of several genes involved in the hypothalamic-pituitary-interrenal response to stress and epigenetic processes such as the regulation of DNA methylation patterns and miRNAs increased in males and not in females. These data suggest that maternal stress has markedly different effects on cellular pathways in the brains of male and female offspring of mothers that are exposed to stress, which could have important implications when assessing the long-term ecological and evolutionary impacts of stress across generations.
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Affiliation(s)
- David C H Metzger
- Department of Zoology, 6270 University Boulevard, University of British Columbia, Vancouver, BC, Canada V6T 1Z4
| | - Patricia M Schulte
- Department of Zoology, 6270 University Boulevard, University of British Columbia, Vancouver, BC, Canada V6T 1Z4
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27
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Dennenmoser S, Vamosi SM, Nolte AW, Rogers SM. Adaptive genomic divergence under high gene flow between freshwater and brackish-water ecotypes of prickly sculpin (Cottus asper) revealed by Pool-Seq. Mol Ecol 2016; 26:25-42. [DOI: 10.1111/mec.13805] [Citation(s) in RCA: 52] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2016] [Revised: 07/29/2016] [Accepted: 08/11/2016] [Indexed: 12/19/2022]
Affiliation(s)
- Stefan Dennenmoser
- Max-Planck Institute for Evolutionary Biology; August Thienemann Strasse 2 24306 Plön Germany
- Department of Biological Sciences; University of Calgary; 2500 University Drive NW Calgary AB Canada T2N 1N4
| | - Steven M. Vamosi
- Department of Biological Sciences; University of Calgary; 2500 University Drive NW Calgary AB Canada T2N 1N4
| | - Arne W. Nolte
- Max-Planck Institute for Evolutionary Biology; August Thienemann Strasse 2 24306 Plön Germany
- Institute for Biology; Carl von Ossietzky University Oldenburg; Carl von Ossietzky Str. 9-11 26111 Oldenburg Germany
| | - Sean M. Rogers
- Department of Biological Sciences; University of Calgary; 2500 University Drive NW Calgary AB Canada T2N 1N4
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28
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Yoshida K, Makino T, Kitano J. Accumulation of Deleterious Mutations on the Neo-Y Chromosome of Japan Sea Stickleback (Gasterosteus nipponicus). J Hered 2016; 108:63-68. [DOI: 10.1093/jhered/esw054] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2016] [Accepted: 08/22/2016] [Indexed: 12/22/2022] Open
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29
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Toli EA, Calboli FCF, Shikano T, Merilä J. A universal and reliable assay for molecular sex identification of three-spined sticklebacks (Gasterosteus aculeatus). Mol Ecol Resour 2016; 16:1389-1400. [PMID: 27238091 DOI: 10.1111/1755-0998.12543] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2016] [Revised: 05/20/2016] [Accepted: 05/20/2016] [Indexed: 11/27/2022]
Abstract
In heterogametic species, biological differences between the two sexes are ubiquitous, and hence, errors in sex identification can be a significant source of noise and bias in studies where sex-related sources of variation are of interest or need to be controlled for. We developed and validated a universal multimarker assay for reliable sex identification of three-spined sticklebacks (Gasterosteus aculeatus). The assay makes use of genotype scores from three sex-linked loci and utilizes Bayesian probabilistic inference to identify sex of the genotyped individuals. The results, validated with 286 phenotypically sexed individuals from six populations of sticklebacks representing all major genetic lineages (cf. Pacific, Atlantic and Japan Sea), indicate that in contrast to commonly used single-marker-based sex identification assays, the developed multimarker assay should be 100% accurate. As the markers in the assay can be scored from agarose gels, it provides a quick and cost-efficient tool for universal sex identification of three-spined sticklebacks. The general principle of combining information from multiple markers to improve the reliability of sex identification is transferable and can be utilized to develop and validate similar assays for other species.
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Affiliation(s)
- E-A Toli
- Ecological Genetics Research Unit, Department of Biosciences, University of Helsinki, P.O. Box 65, Helsinki, FI-00014, Finland.,Molecular Ecology & Conservation Genetics Lab, Department of Biological Applications & Technology, University of Ioannina, Ioannina, GR-45110, Greece
| | - F C F Calboli
- Ecological Genetics Research Unit, Department of Biosciences, University of Helsinki, P.O. Box 65, Helsinki, FI-00014, Finland
| | - T Shikano
- Ecological Genetics Research Unit, Department of Biosciences, University of Helsinki, P.O. Box 65, Helsinki, FI-00014, Finland
| | - J Merilä
- Ecological Genetics Research Unit, Department of Biosciences, University of Helsinki, P.O. Box 65, Helsinki, FI-00014, Finland.
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30
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Zimmer F, Harrison PW, Dessimoz C, Mank JE. Compensation of Dosage-Sensitive Genes on the Chicken Z Chromosome. Genome Biol Evol 2016; 8:1233-42. [PMID: 27044516 PMCID: PMC4860703 DOI: 10.1093/gbe/evw075] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 03/26/2016] [Indexed: 12/15/2022] Open
Abstract
In many diploid species, sex determination is linked to a pair of sex chromosomes that evolved from a pair of autosomes. In these organisms, the degeneration of the sex-limited Y or W chromosome causes a reduction in gene dose in the heterogametic sex for X- or Z-linked genes. Variations in gene dose are detrimental for large chromosomal regions when they span dosage-sensitive genes, and many organisms were thought to evolve complete mechanisms of dosage compensation to mitigate this. However, the recent realization that a wide variety of organisms lack complete mechanisms of sex chromosome dosage compensation has presented a perplexing question: How do organisms with incomplete dosage compensation avoid deleterious effects of gene dose differences between the sexes? Here we use expression data from the chicken (Gallus gallus) to show that ohnologs, duplicated genes known to be dosage-sensitive, are preferentially dosage-compensated on the chicken Z chromosome. Our results indicate that even in the absence of a complete and chromosome wide dosage compensation mechanism, dosage-sensitive genes are effectively dosage compensated on the Z chromosome.
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Affiliation(s)
- Fabian Zimmer
- Department of Genetics Evolution and Environment, University College London, London, United Kingdom
| | - Peter W Harrison
- Department of Genetics Evolution and Environment, University College London, London, United Kingdom
| | - Christophe Dessimoz
- Department of Genetics Evolution and Environment, University College London, London, United Kingdom Department of Ecology and Evolution & Center for Integrative Genomics, University of Lausanne, Biophore 1015, Lausanne, Switzerland Swiss Institute of Bioinformatics, Biophore, 1015 Lausanne, Switzerland
| | - Judith E Mank
- Department of Genetics Evolution and Environment, University College London, London, United Kingdom
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31
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Abstract
Differentiated sex chromosomes in mammals and other vertebrates evolved independently but in strikingly similar ways. Vertebrates with differentiated sex chromosomes share the problems of the unequal expression of the genes borne on sex chromosomes, both between the sexes and with respect to autosomes. Dosage compensation of genes on sex chromosomes is surprisingly variable - and can even be absent - in different vertebrate groups. Systems that compensate for different gene dosages include a wide range of global, regional and gene-by-gene processes that differ in their extent and their molecular mechanisms. However, many elements of these control systems are similar across distant phylogenetic divisions and show parallels to other gene silencing systems. These dosage systems cannot be identical by descent but were probably constructed from elements of ancient silencing mechanisms that are ubiquitous among vertebrates and shared throughout eukaryotes.
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32
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Estimating tempo and mode of Y chromosome turnover: explaining Y chromosome loss with the fragile Y hypothesis. Genetics 2015; 197:561-72. [PMID: 24939995 DOI: 10.1534/genetics.114.164269] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Chromosomal sex determination is phylogenetically widespread, having arisen independently in many lineages. Decades of theoretical work provide predictions about sex chromosome differentiation that are well supported by observations in both XY and ZW systems. However, the phylogenetic scope of previous work gives us a limited understanding of the pace of sex chromosome gain and loss and why Y or W chromosomes are more often lost in some lineages than others, creating XO or ZO systems. To gain phylogenetic breadth we therefore assembled a database of 4724 beetle species' karyotypes and found substantial variation in sex chromosome systems. We used the data to estimate rates of Y chromosome gain and loss across a phylogeny of 1126 taxa estimated from seven genes. Contrary to our initial expectations, we find that highly degenerated Y chromosomes of many members of the suborder Polyphaga are rarely lost, and that cases of Y chromosome loss are strongly associated with chiasmatic segregation during male meiosis. We propose the "fragile Y" hypothesis, that recurrent selection to reduce recombination between the X and Y chromosome leads to the evolution of a small pseudoautosomal region (PAR), which, in taxa that require XY chiasmata for proper segregation during meiosis, increases the probability of aneuploid gamete production, with Y chromosome loss. This hypothesis predicts that taxa that evolve achiasmatic segregation during male meiosis will rarely lose the Y chromosome. We discuss data from mammals, which are consistent with our prediction.
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33
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Lipinska A, Cormier A, Luthringer R, Peters AF, Corre E, Gachon CMM, Cock JM, Coelho SM. Sexual dimorphism and the evolution of sex-biased gene expression in the brown alga ectocarpus. Mol Biol Evol 2015; 32:1581-97. [PMID: 25725430 DOI: 10.1093/molbev/msv049] [Citation(s) in RCA: 72] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Males and females often have marked phenotypic differences, and the expression of these dissimilarities invariably involves sex differences in gene expression. Sex-biased gene expression has been well characterized in animal species, where a high proportion of the genome may be differentially regulated in males and females during development. Male-biased genes tend to evolve more rapidly than female-biased genes, implying differences in the strength of the selective forces acting on the two sexes. Analyses of sex-biased gene expression have focused on organisms that exhibit separate sexes during the diploid phase of the life cycle (diploid sexual systems), but the genetic nature of the sexual system is expected to influence the evolutionary trajectories of sex-biased genes. We analyze here the patterns of sex-biased gene expression in Ectocarpus, a brown alga with haploid sex determination (dioicy) and a low level of phenotypic sexual dimorphism. In Ectocarpus, female-biased genes were found to be evolving as rapidly as male-biased genes. Moreover, genes expressed at fertility showed faster rates of evolution than genes expressed in immature gametophytes. Both male- and female-biased genes had a greater proportion of sites experiencing positive selection, suggesting that their accelerated evolution is at least partly driven by adaptive evolution. Gene duplication appears to have played a significant role in the generation of sex-biased genes in Ectocarpus, expanding previous models that propose this mechanism for the resolution of sexual antagonism in diploid systems. The patterns of sex-biased gene expression in Ectocarpus are consistent both with predicted characteristics of UV (haploid) sexual systems and with the distinctive aspects of this organism's reproductive biology.
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Affiliation(s)
- Agnieszka Lipinska
- Sorbonne Université, UPMC Univ Paris 06, CNRS, Algal Genetics Group, UMR 8227, Integrative Biology of Marine Models, Station Biologique de Roscoff, CS 90074, F-29688, Roscoff, France
| | - Alexandre Cormier
- Sorbonne Université, UPMC Univ Paris 06, CNRS, Algal Genetics Group, UMR 8227, Integrative Biology of Marine Models, Station Biologique de Roscoff, CS 90074, F-29688, Roscoff, France
| | - Rémy Luthringer
- Sorbonne Université, UPMC Univ Paris 06, CNRS, Algal Genetics Group, UMR 8227, Integrative Biology of Marine Models, Station Biologique de Roscoff, CS 90074, F-29688, Roscoff, France
| | | | - Erwan Corre
- Abims Platform, CNRS-UPMC, FR2424, Station Biologique de Roscoff, Roscoff, France
| | - Claire M M Gachon
- Microbial and Molecular Biology Department, Scottish Marine Institute, Scottish Association for Marine Science, Oban, United Kingdom
| | - J Mark Cock
- Sorbonne Université, UPMC Univ Paris 06, CNRS, Algal Genetics Group, UMR 8227, Integrative Biology of Marine Models, Station Biologique de Roscoff, CS 90074, F-29688, Roscoff, France
| | - Susana M Coelho
- Sorbonne Université, UPMC Univ Paris 06, CNRS, Algal Genetics Group, UMR 8227, Integrative Biology of Marine Models, Station Biologique de Roscoff, CS 90074, F-29688, Roscoff, France
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34
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White MA, Kitano J, Peichel CL. Purifying Selection Maintains Dosage-Sensitive Genes during Degeneration of the Threespine Stickleback Y Chromosome. Mol Biol Evol 2015; 32:1981-95. [PMID: 25818858 DOI: 10.1093/molbev/msv078] [Citation(s) in RCA: 64] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
Sex chromosomes are subject to unique evolutionary forces that cause suppression of recombination, leading to sequence degeneration and the formation of heteromorphic chromosome pairs (i.e., XY or ZW). Although progress has been made in characterizing the outcomes of these evolutionary processes on vertebrate sex chromosomes, it is still unclear how recombination suppression and sequence divergence typically occur and how gene dosage imbalances are resolved in the heterogametic sex. The threespine stickleback fish (Gasterosteus aculeatus) is a powerful model system to explore vertebrate sex chromosome evolution, as it possesses an XY sex chromosome pair at relatively early stages of differentiation. Using a combination of whole-genome and transcriptome sequencing, we characterized sequence evolution and gene expression across the sex chromosomes. We uncovered two distinct evolutionary strata that correspond with known structural rearrangements on the Y chromosome. In the oldest stratum, only a handful of genes remain, and these genes are under strong purifying selection. By comparing sex-linked gene expression with expression of autosomal orthologs in an outgroup, we show that dosage compensation has not evolved in threespine sticklebacks through upregulation of the X chromosome in males. Instead, in the oldest stratum, the genes that still possess a Y chromosome allele are enriched for genes predicted to be dosage sensitive in mammals and yeast. Our results suggest that dosage imbalances may have been avoided at haploinsufficient genes by retaining function of the Y chromosome allele through strong purifying selection.
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Affiliation(s)
- Michael A White
- Divisions of Human Biology and Basic Sciences, Fred Hutchinson Cancer Research Center, Seattle, WA
| | - Jun Kitano
- Ecological Genetics Laboratory, National Institute of Genetics, Shizuoka, Japan
| | - Catherine L Peichel
- Divisions of Human Biology and Basic Sciences, Fred Hutchinson Cancer Research Center, Seattle, WA
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Leder EH, McCairns RJS, Leinonen T, Cano JM, Viitaniemi HM, Nikinmaa M, Primmer CR, Merilä J. The evolution and adaptive potential of transcriptional variation in sticklebacks--signatures of selection and widespread heritability. Mol Biol Evol 2015; 32:674-89. [PMID: 25429004 PMCID: PMC4327155 DOI: 10.1093/molbev/msu328] [Citation(s) in RCA: 65] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Evidence implicating differential gene expression as a significant driver of evolutionary novelty continues to accumulate, but our understanding of the underlying sources of variation in expression, both environmental and genetic, is wanting. Heritability in particular may be underestimated when inferred from genetic mapping studies, the predominant "genetical genomics" approach to the study of expression variation. Such uncertainty represents a fundamental limitation to testing for adaptive evolution at the transcriptomic level. By studying the inheritance of expression levels in 10,495 genes (10,527 splice variants) in a threespine stickleback pedigree consisting of 563 individuals, half of which were subjected to a thermal treatment, we show that 74-98% of transcripts exhibit significant additive genetic variance. Dominance variance is also prevalent (41-99% of transcripts), and genetic sources of variation seem to play a more significant role in expression variance in the liver than a key environmental variable, temperature. Among-population comparisons suggest that the majority of differential expression in the liver is likely due to neutral divergence; however, we also show that signatures of directional selection may be more prevalent than those of stabilizing selection. This predominantly aligns with the neutral model of evolution for gene expression but also suggests that natural selection may still act on transcriptional variation in the wild. As genetic variation both within- and among-populations ultimately defines adaptive potential, these results indicate that broad adaptive potential may be found within the transcriptome.
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Affiliation(s)
- Erica H Leder
- Division of Genetics and Physiology, Department of Biology, University of Turku, Turku, Finland
| | - R J Scott McCairns
- Ecological Genetics Research Unit, Department of Biosciences, University of Helsinki, Helsinki, Finland
| | - Tuomas Leinonen
- Ecological Genetics Research Unit, Department of Biosciences, University of Helsinki, Helsinki, Finland
| | - José M Cano
- Research Unit of Biodiversity (UO-CSIC-PA), University of Oviedo, Mieres, Spain
| | - Heidi M Viitaniemi
- Division of Genetics and Physiology, Department of Biology, University of Turku, Turku, Finland
| | - Mikko Nikinmaa
- Division of Genetics and Physiology, Department of Biology, University of Turku, Turku, Finland
| | - Craig R Primmer
- Division of Genetics and Physiology, Department of Biology, University of Turku, Turku, Finland
| | - Juha Merilä
- Ecological Genetics Research Unit, Department of Biosciences, University of Helsinki, Helsinki, Finland
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36
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Lappin FM, Medert CM, Hawkins KK, Mardonovich S, Wu M, Moore RC. A polymorphic pseudoautosomal boundary in the Carica papaya sex chromosomes. Mol Genet Genomics 2015; 290:1511-22. [DOI: 10.1007/s00438-015-1000-3] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2014] [Accepted: 01/23/2015] [Indexed: 12/14/2022]
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37
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Schultheiß R, Viitaniemi HM, Leder EH. Spatial dynamics of evolving dosage compensation in a young sex chromosome system. Genome Biol Evol 2015; 7:581-90. [PMID: 25618140 PMCID: PMC4350182 DOI: 10.1093/gbe/evv013] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023] Open
Abstract
The loss of Y-linked genes during sex chromosome evolution creates a potentially deleterious low gene dosage in males. Recent studies have reported different strategies of dosage compensation. Unfortunately, most of these studies investigated taxa with comparatively old sex chromosome systems, which may limit insights into the evolution of dosage compensation and thus into the causes of different compensation strategies. Using deep RNA sequencing, we investigate differential expression patterns along the young XY chromosomes of threespine sticklebacks. Our strata-specific analyses provide new insights into the spatial patterns during the early stages of the evolution of dosage compensation. In particular, our results indicate systematic upregulation of male gene expression in stratum II, which in turn causes female hypertranscription in the same stratum. These findings are consistent with theoretical predictions that selection during early stages of sex chromosome evolution is stronger for a compensating upregulation in males than for the countercompensation of female hyperexpression. In contrast, no elevated gene expression is detectable in stratum I. We argue that strata-specific differences in compensating male gene expression may evolve in response to differences in the prevailing mechanism of Y chromosome degeneration.
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Affiliation(s)
- Roland Schultheiß
- Division of Genetics and Physiology, Department of Biology, University of Turku, Finland
| | - Heidi M Viitaniemi
- Division of Genetics and Physiology, Department of Biology, University of Turku, Finland
| | - Erica H Leder
- Division of Genetics and Physiology, Department of Biology, University of Turku, Finland
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38
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Mahajan S, Bachtrog D. Partial dosage compensation in Strepsiptera, a sister group of beetles. Genome Biol Evol 2015; 7:591-600. [PMID: 25601100 PMCID: PMC4350179 DOI: 10.1093/gbe/evv008] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
Sex chromosomes have evolved independently in many different taxa, and so have mechanisms to compensate for expression differences on sex chromosomes in males and females. Different clades have evolved vastly different ways to achieve dosage compensation, including hypertranscription of the single X in male Drosophila, downregulation of both X's in XX Caenorhabditis, or inactivation of one X in female mammals. In the flour beetle Tribolium, the X appears hyperexpressed in both sexes, which might represent the first of two steps to evolve dosage compensation along the paths mammals may have taken (i.e., upregulation of X in both sexes, followed by inactivation of one X in females). Here we test for dosage compensation in Strepsiptera, a sister taxon to beetles. We identify sex-linked chromosomes in Xenos vesparum based on genomic analysis of males and females, and show that its sex chromosome consists of two chromosomal arms in Tribolium: The X chromosome that is shared between Tribolium and Strepsiptera, and another chromosome that is autosomal in Tribolium and another distantly related Strepsiptera species, but sex-linked in X. vesparum. We use RNA-seq (RNA sequencing) to show that dosage compensation along the X of X. vesparum is partial and heterogeneous. In particular, genes that are X-linked in both beetles and Strepsiptera appear fully dosage compensated probably through downregulation in both sexes, whereas genes on the more recently added X segment have evolved only partial dosage compensation. In addition, reanalysis of published RNA-seq data suggests that Tribolium has evolved dosage compensation, without hypertranscribing the X in females. Our results demonstrate that patterns of dosage compensation are highly variable across sex-determination systems and even within species.
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Affiliation(s)
- Shivani Mahajan
- Department of Integrative Biology, University of California Berkeley
| | - Doris Bachtrog
- Department of Integrative Biology, University of California Berkeley
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Ingleby FC, Flis I, Morrow EH. Sex-biased gene expression and sexual conflict throughout development. Cold Spring Harb Perspect Biol 2014; 7:a017632. [PMID: 25376837 DOI: 10.1101/cshperspect.a017632] [Citation(s) in RCA: 54] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
Sex-biased gene expression is likely to account for most sexually dimorphic traits because males and females share much of their genome. When fitness optima differ between sexes for a shared trait, sexual dimorphism can allow each sex to express their optimum trait phenotype, and in this way, the evolution of sex-biased gene expression is one mechanism that could help to resolve intralocus sexual conflict. Genome-wide patterns of sex-biased gene expression have been identified in a number of studies, which we review here. However, very little is known about how sex-biased gene expression relates to sex-specific fitness and about how sex-biased gene expression and conflict vary throughout development or across different genotypes, populations, and environments. We discuss the importance of these neglected areas of research and use data from a small-scale experiment on sex-specific expression of genes throughout development to highlight potentially interesting avenues for future research.
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Affiliation(s)
- Fiona C Ingleby
- Evolution, Behaviour and Environment Group, School of Life Sciences, University of Sussex, John Maynard Smith Building, Falmer, Brighton BN1 9QG, United Kingdom
| | - Ilona Flis
- Evolution, Behaviour and Environment Group, School of Life Sciences, University of Sussex, John Maynard Smith Building, Falmer, Brighton BN1 9QG, United Kingdom
| | - Edward H Morrow
- Evolution, Behaviour and Environment Group, School of Life Sciences, University of Sussex, John Maynard Smith Building, Falmer, Brighton BN1 9QG, United Kingdom
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Smith G, Chen YR, Blissard GW, Briscoe AD. Complete dosage compensation and sex-biased gene expression in the moth Manduca sexta. Genome Biol Evol 2014; 6:526-37. [PMID: 24558255 PMCID: PMC3971586 DOI: 10.1093/gbe/evu035] [Citation(s) in RCA: 45] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/03/2022] Open
Abstract
Sex chromosome dosage compensation balances homogametic sex chromosome expression with autosomal expression in the heterogametic sex, leading to sex chromosome expression parity between the sexes. If compensation is incomplete, this can lead to expression imbalance and sex-biased gene expression. Recent work has uncovered an intriguing and variable pattern of dosage compensation across species that includes a lack of complete dosage compensation in ZW species compared with XY species. This has led to the hypothesis that ZW species do not require complete compensation or that complete compensation would negatively affect their fitness. To date, only one study, a study of the moth Bombyx mori, has discovered evidence for complete dosage compensation in a ZW species. We examined another moth species, Manduca sexta, using high-throughput sequencing to survey gene expression in the head tissue of males and females. We found dosage compensation to be complete in M. sexta with average expression between the Z chromosome in males and females being equal. When genes expressed at very low levels are removed by filtering, we found that average autosome expression was highly similar to average Z expression, suggesting that the majority of genes in M. sexta are completely dosage compensated. Further, this compensation was accompanied by sex-specific gene expression associated with important sexually dimorphic traits. We suggest that complete dosage compensation in ZW species might be more common than previously appreciated and linked to additional selective processes, such as sexual selection. More ZW and lepidopteran species should now be examined in a phylogenetic framework, to understand the evolution of dosage compensation.
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Affiliation(s)
- Gilbert Smith
- Department of Ecology and Evolutionary Biology, University of California, Irvine
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Papakostas S, Vøllestad LA, Bruneaux M, Aykanat T, Vanoverbeke J, Ning M, Primmer CR, Leder EH. Gene pleiotropy constrains gene expression changes in fish adapted to different thermal conditions. Nat Commun 2014; 5:4071. [PMID: 24892934 PMCID: PMC4059932 DOI: 10.1038/ncomms5071] [Citation(s) in RCA: 61] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2014] [Accepted: 05/08/2014] [Indexed: 02/07/2023] Open
Abstract
Understanding the factors that shape the evolution of gene expression is a central goal in biology, but the molecular mechanisms behind this remain controversial. A related major goal is ascertaining how such factors may affect the adaptive potential of a species or population. Here we demonstrate that temperature-driven gene expression changes in fish adapted to differing thermal environments are constrained by the level of gene pleiotropy estimated by either the number of protein interactions or gene biological processes. Genes with low pleiotropy levels were the main drivers of both plastic and evolutionary global expression profile changes, while highly pleiotropic genes had limited expression response to temperature treatment. Our study provides critical insights into the molecular mechanisms by which natural populations can adapt to changing environments. In addition to having important implications for climate change adaptation, these results suggest that gene pleiotropy should be considered more carefully when interpreting expression profiling data. The factors that shape the evolution of gene expression and their role in adaptation are poorly understood. Here, Papakostas et al. show that gene pleiotropy constrains protein expression evolution in freshwater salmonids adapted to different temperatures.
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Affiliation(s)
- Spiros Papakostas
- Division of Genetics and Physiology, Department of Biology, University of Turku, Pharmacity, Itäinen Pitkäkatu 4, 20520 Turku, Finland
| | - L Asbjørn Vøllestad
- Centre for Ecological and Evolutionary Synthesis (CEES), Department of Biosciences, University of Oslo, P.O. Box 1066 Blindern, NO-0316 Oslo, Norway
| | - Matthieu Bruneaux
- Division of Genetics and Physiology, Department of Biology, University of Turku, Pharmacity, Itäinen Pitkäkatu 4, 20520 Turku, Finland
| | - Tutku Aykanat
- Division of Genetics and Physiology, Department of Biology, University of Turku, Pharmacity, Itäinen Pitkäkatu 4, 20520 Turku, Finland
| | - Joost Vanoverbeke
- Laboratory of Aquatic Ecology, Evolution and Conservation, Department of Biology, KU Leuven, Ch. Deberiotstraat 32, 3000 Leuven, Belgium
| | - Mei Ning
- 1] Division of Genetics and Physiology, Department of Biology, University of Turku, Pharmacity, Itäinen Pitkäkatu 4, 20520 Turku, Finland [2]
| | - Craig R Primmer
- 1] Division of Genetics and Physiology, Department of Biology, University of Turku, Pharmacity, Itäinen Pitkäkatu 4, 20520 Turku, Finland [2]
| | - Erica H Leder
- 1] Division of Genetics and Physiology, Department of Biology, University of Turku, Pharmacity, Itäinen Pitkäkatu 4, 20520 Turku, Finland [2]
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Sharma E, Künstner A, Fraser BA, Zipprich G, Kottler VA, Henz SR, Weigel D, Dreyer C. Transcriptome assemblies for studying sex-biased gene expression in the guppy, Poecilia reticulata. BMC Genomics 2014; 15:400. [PMID: 24886435 PMCID: PMC4059875 DOI: 10.1186/1471-2164-15-400] [Citation(s) in RCA: 59] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2014] [Accepted: 05/09/2014] [Indexed: 01/22/2023] Open
Abstract
BACKGROUND Sexually dimorphic phenotypes are generally associated with differential gene expression between the sexes. The study of molecular evolution and genomic location of these differentially expressed, or sex-biased, genes is important for understanding inter-sexual divergence under sex-specific selection pressures. Teleost fish provide a unique opportunity to examine this divergence in the presence of variable sex-determination mechanisms of recent origin. The guppy, Poecilia reticulata, displays sexual dimorphism in size, ornaments, and behavior, traits shaped by natural and sexual selection in the wild. RESULTS To gain insight into molecular mechanisms underlying the guppy's sexual dimorphism, we assembled a reference transcriptome combining genome-independent as well as genome-guided assemblies and analyzed sex-biased gene expression between different tissues of adult male and female guppies. We found tissue-associated sex-biased expression of genes related to pigmentation, signal transduction, and spermatogenesis in males; and growth, cell-division, extra-cellular matrix organization, nutrient transport, and folliculogenesis in females. While most sex-biased genes were randomly distributed across linkage groups, we observed accumulation of ovary-biased genes on the sex linkage group, LG12. Both testis-biased and ovary-biased genes showed a significantly higher rate of non-synonymous to synonymous substitutions (dN/dS) compared to unbiased genes. However, in somatic tissues only female-biased genes, including those co-expressed in multiple tissues, showed elevated ratios of non-synonymous substitutions. CONCLUSIONS Our work identifies a set of annotated gene products that are candidate factors affecting sexual dimorphism in guppies. The differential genomic distribution of gonad-biased genes provides evidence for sex-specific selection pressures acting on the nascent sex chromosomes of the guppy. The elevated rates of evolution of testis-biased and female-biased genes indicate differing evolution under distinct selection pressures on the reproductive versus non-reproductive tissues.
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Affiliation(s)
| | - Axel Künstner
- Department of Molecular Biology, Max Planck Institute for Developmental Biology, Spemannstrasse 37, 72076 Tübingen, Germany.
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Identification of major and minor QTL for ecologically important morphological traits in three-spined sticklebacks (Gasterosteus aculeatus). G3-GENES GENOMES GENETICS 2014; 4:595-604. [PMID: 24531726 PMCID: PMC4059232 DOI: 10.1534/g3.114.010389] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
Quantitative trait locus (QTL) mapping studies of Pacific three-spined sticklebacks (Gasterosteus aculeatus) have uncovered several genomic regions controlling variability in different morphological traits, but QTL studies of Atlantic sticklebacks are lacking. We mapped QTL for 40 morphological traits, including body size, body shape, and body armor, in a F2 full-sib cross between northern European marine and freshwater three-spined sticklebacks. A total of 52 significant QTL were identified at the 5% genome-wide level. One major QTL explaining 74.4% of the total variance in lateral plate number was detected on LG4, whereas several major QTL for centroid size (a proxy for body size), and the lengths of two dorsal spines, pelvic spine, and pelvic girdle were mapped on LG21 with the explained variance ranging from 27.9% to 57.6%. Major QTL for landmark coordinates defining body shape variation also were identified on LG21, with each explaining ≥15% of variance in body shape. Multiple QTL for different traits mapped on LG21 overlapped each other, implying pleiotropy and/or tight linkage. Thus, apart from providing confirmatory data to support conclusions born out of earlier QTL studies of Pacific sticklebacks, this study also describes several novel QTL of both major and smaller effect for ecologically important traits. The finding that many major QTL mapped on LG21 suggests that this linkage group might be a hotspot for genetic determinants of ecologically important morphological traits in three-spined sticklebacks.
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Charlesworth B, Jordan CY, Charlesworth D. The evolutionary dynamics of sexually antagonistic mutations in pseudoautosomal regions of sex chromosomes. Evolution 2014; 68:1339-50. [PMID: 24476564 PMCID: PMC4289941 DOI: 10.1111/evo.12364] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2013] [Accepted: 01/08/2014] [Indexed: 11/30/2022]
Abstract
Sex chromosomes can evolve gene contents that differ from the rest of the genome, as well as larger sex differences in gene expression compared with autosomes. This probably occurs because fully sex-linked beneficial mutations substitute at different rates from autosomal ones, especially when fitness effects are sexually antagonistic (SA). The evolutionary properties of genes located in the recombining pseudoautosomal region (PAR) of a sex chromosome have not previously been modeled in detail. Such PAR genes differ from classical sex-linked genes by having two alleles at a locus in both sexes; in contrast to autosomal genes, however, variants can become associated with gender. The evolutionary fates of PAR genes may therefore differ from those of either autosomal or fully sex-linked genes. Here, we model their evolutionary dynamics by deriving expressions for the selective advantages of PAR gene mutations under different conditions. We show that, unless selection is very strong, the probability of invasion of a population by an SA mutation is usually similar to that of an autosomal mutation, unless there is close linkage to the sex-determining region. Most PAR genes should thus evolve similarly to autosomal rather than sex-linked genes, unless recombination is very rare in the PAR.
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Affiliation(s)
- Brian Charlesworth
- Institute of Evolutionary Biology, Ashworth Laboratory, School of Biological Sciences, The University of Edinburgh, King's Buildings, West Mains Road, Edinburgh EH9 3JT, United Kingdom
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Yoshida K, Makino T, Yamaguchi K, Shigenobu S, Hasebe M, Kawata M, Kume M, Mori S, Peichel CL, Toyoda A, Fujiyama A, Kitano J. Sex chromosome turnover contributes to genomic divergence between incipient stickleback species. PLoS Genet 2014; 10:e1004223. [PMID: 24625862 PMCID: PMC3953013 DOI: 10.1371/journal.pgen.1004223] [Citation(s) in RCA: 69] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2013] [Accepted: 01/22/2014] [Indexed: 12/30/2022] Open
Abstract
Sex chromosomes turn over rapidly in some taxonomic groups, where closely related species have different sex chromosomes. Although there are many examples of sex chromosome turnover, we know little about the functional roles of sex chromosome turnover in phenotypic diversification and genomic evolution. The sympatric pair of Japanese threespine stickleback (Gasterosteus aculeatus) provides an excellent system to address these questions: the Japan Sea species has a neo-sex chromosome system resulting from a fusion between an ancestral Y chromosome and an autosome, while the sympatric Pacific Ocean species has a simple XY sex chromosome system. Furthermore, previous quantitative trait locus (QTL) mapping demonstrated that the Japan Sea neo-X chromosome contributes to phenotypic divergence and reproductive isolation between these sympatric species. To investigate the genomic basis for the accumulation of genes important for speciation on the neo-X chromosome, we conducted whole genome sequencing of males and females of both the Japan Sea and the Pacific Ocean species. No substantial degeneration has yet occurred on the neo-Y chromosome, but the nucleotide sequence of the neo-X and the neo-Y has started to diverge, particularly at regions near the fusion. The neo-sex chromosomes also harbor an excess of genes with sex-biased expression. Furthermore, genes on the neo-X chromosome showed higher non-synonymous substitution rates than autosomal genes in the Japan Sea lineage. Genomic regions of higher sequence divergence between species, genes with divergent expression between species, and QTL for inter-species phenotypic differences were found not only at the regions near the fusion site, but also at other regions along the neo-X chromosome. Neo-sex chromosomes can therefore accumulate substitutions causing species differences even in the absence of substantial neo-Y degeneration.
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Affiliation(s)
- Kohta Yoshida
- Ecological Genetics Laboratory, National Institute of Genetics, Shizuoka, Japan
| | - Takashi Makino
- Division of Ecology and Evolutionary Biology, Graduate School of Life Sciences, Tohoku University, Miyagi, Japan
| | - Katsushi Yamaguchi
- NIBB Core Research Facilities, National Institute for Basic Biology, Myodaiji, Okazaki, Japan
| | - Shuji Shigenobu
- NIBB Core Research Facilities, National Institute for Basic Biology, Myodaiji, Okazaki, Japan
- School of Life Science, The Graduate University for Advanced Studies, Okazaki, Japan
| | - Mitsuyasu Hasebe
- School of Life Science, The Graduate University for Advanced Studies, Okazaki, Japan
- Division of Evolutionary Biology, National Institute for Basic Biology, Myodaiji, Okazaki, Japan
| | - Masakado Kawata
- Division of Ecology and Evolutionary Biology, Graduate School of Life Sciences, Tohoku University, Miyagi, Japan
| | - Manabu Kume
- Biological Laboratories, Gifu-keizai-University, Gifu, Japan
| | - Seiichi Mori
- Biological Laboratories, Gifu-keizai-University, Gifu, Japan
| | - Catherine L. Peichel
- Divisions of Human Biology and Basic Sciences, Fred Hutchinson Cancer Research Center, Seattle, Washington, United States of America
| | - Atsushi Toyoda
- Comparative Genomics Laboratory, National Institute of Genetics, Shizuoka, Japan
| | - Asao Fujiyama
- Comparative Genomics Laboratory, National Institute of Genetics, Shizuoka, Japan
| | - Jun Kitano
- Ecological Genetics Laboratory, National Institute of Genetics, Shizuoka, Japan
- PRESTO, Japan Science and Technology Agency, Saitama, Japan
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46
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Mank JE. Sex chromosome dosage compensation: definitely not for everyone. Trends Genet 2013; 29:677-83. [DOI: 10.1016/j.tig.2013.07.005] [Citation(s) in RCA: 121] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2013] [Revised: 07/03/2013] [Accepted: 07/23/2013] [Indexed: 10/26/2022]
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Sun F, Liu S, Gao X, Jiang Y, Perera D, Wang X, Li C, Sun L, Zhang J, Kaltenboeck L, Dunham R, Liu Z. Male-biased genes in catfish as revealed by RNA-Seq analysis of the testis transcriptome. PLoS One 2013; 8:e68452. [PMID: 23874634 PMCID: PMC3709890 DOI: 10.1371/journal.pone.0068452] [Citation(s) in RCA: 57] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2013] [Accepted: 05/29/2013] [Indexed: 11/29/2022] Open
Abstract
Background Catfish has a male-heterogametic (XY) sex determination system, but genes involved in gonadogenesis, spermatogenesis, testicular determination, and sex determination are poorly understood. As a first step of understanding the transcriptome of the testis, here, we conducted RNA-Seq analysis using high throughput Illumina sequencing. Methodology/Principal Findings A total of 269.6 million high quality reads were assembled into 193,462 contigs with a N50 length of 806 bp. Of these contigs, 67,923 contigs had hits to a set of 25,307 unigenes, including 167 unique genes that had not been previously identified in catfish. A meta-analysis of expressed genes in the testis and in the gynogen (double haploid female) allowed the identification of 5,450 genes that are preferentially expressed in the testis, providing a pool of putative male-biased genes. Gene ontology and annotation analysis suggested that many of these male-biased genes were involved in gonadogenesis, spermatogenesis, testicular determination, gametogenesis, gonad differentiation, and possibly sex determination. Conclusion/Significance We provide the first transcriptome-level analysis of the catfish testis. Our analysis would lay the basis for sequential follow-up studies of genes involved in sex determination and differentiation in catfish.
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Affiliation(s)
- Fanyue Sun
- The Fish Molecular Genetics and Biotechnology Laboratory, Department of Fisheries and Allied Aquacultures and Program of Cell and Molecular Biosciences, Aquatic Genomics Unit, Auburn University, Auburn, Alabama, United States of America
| | - Shikai Liu
- The Fish Molecular Genetics and Biotechnology Laboratory, Department of Fisheries and Allied Aquacultures and Program of Cell and Molecular Biosciences, Aquatic Genomics Unit, Auburn University, Auburn, Alabama, United States of America
| | - Xiaoyu Gao
- The Fish Molecular Genetics and Biotechnology Laboratory, Department of Fisheries and Allied Aquacultures and Program of Cell and Molecular Biosciences, Aquatic Genomics Unit, Auburn University, Auburn, Alabama, United States of America
| | - Yanliang Jiang
- The Fish Molecular Genetics and Biotechnology Laboratory, Department of Fisheries and Allied Aquacultures and Program of Cell and Molecular Biosciences, Aquatic Genomics Unit, Auburn University, Auburn, Alabama, United States of America
| | - Dayan Perera
- The Fish Molecular Genetics and Biotechnology Laboratory, Department of Fisheries and Allied Aquacultures and Program of Cell and Molecular Biosciences, Aquatic Genomics Unit, Auburn University, Auburn, Alabama, United States of America
| | - Xiuli Wang
- The Fish Molecular Genetics and Biotechnology Laboratory, Department of Fisheries and Allied Aquacultures and Program of Cell and Molecular Biosciences, Aquatic Genomics Unit, Auburn University, Auburn, Alabama, United States of America
| | - Chao Li
- The Fish Molecular Genetics and Biotechnology Laboratory, Department of Fisheries and Allied Aquacultures and Program of Cell and Molecular Biosciences, Aquatic Genomics Unit, Auburn University, Auburn, Alabama, United States of America
| | - Luyang Sun
- The Fish Molecular Genetics and Biotechnology Laboratory, Department of Fisheries and Allied Aquacultures and Program of Cell and Molecular Biosciences, Aquatic Genomics Unit, Auburn University, Auburn, Alabama, United States of America
| | - Jiaren Zhang
- The Fish Molecular Genetics and Biotechnology Laboratory, Department of Fisheries and Allied Aquacultures and Program of Cell and Molecular Biosciences, Aquatic Genomics Unit, Auburn University, Auburn, Alabama, United States of America
| | - Ludmilla Kaltenboeck
- The Fish Molecular Genetics and Biotechnology Laboratory, Department of Fisheries and Allied Aquacultures and Program of Cell and Molecular Biosciences, Aquatic Genomics Unit, Auburn University, Auburn, Alabama, United States of America
| | - Rex Dunham
- The Fish Molecular Genetics and Biotechnology Laboratory, Department of Fisheries and Allied Aquacultures and Program of Cell and Molecular Biosciences, Aquatic Genomics Unit, Auburn University, Auburn, Alabama, United States of America
| | - Zhanjiang Liu
- The Fish Molecular Genetics and Biotechnology Laboratory, Department of Fisheries and Allied Aquacultures and Program of Cell and Molecular Biosciences, Aquatic Genomics Unit, Auburn University, Auburn, Alabama, United States of America
- * E-mail:
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Primmer CR, Papakostas S, Leder EH, Davis MJ, Ragan MA. Annotated genes and nonannotated genomes: cross-species use of Gene Ontology in ecology and evolution research. Mol Ecol 2013; 22:3216-41. [DOI: 10.1111/mec.12309] [Citation(s) in RCA: 68] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2012] [Revised: 02/22/2013] [Accepted: 02/26/2013] [Indexed: 02/01/2023]
Affiliation(s)
- C. R. Primmer
- Department of Biology; University of Turku; 20014 Turku Finland
| | - S. Papakostas
- Department of Biology; University of Turku; 20014 Turku Finland
| | - E. H. Leder
- Department of Biology; University of Turku; 20014 Turku Finland
| | - M. J. Davis
- Institute for Molecular Bioscience; The University of Queensland; Brisbane Qld 4072 Australia
| | - M. A. Ragan
- Institute for Molecular Bioscience; The University of Queensland; Brisbane Qld 4072 Australia
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DeFaveri J, Jonsson PR, Merilä J. Heterogeneous Genomic Differentiation in marine threespine sticklebacks: adaptation along an environmental gradient. Evolution 2013; 67:2530-46. [PMID: 24033165 DOI: 10.1111/evo.12097] [Citation(s) in RCA: 58] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2012] [Accepted: 02/18/2013] [Indexed: 02/03/2023]
Abstract
Evolutionary divergence among populations occupying ecologically distinct environments can occur even in the face of on-going gene flow. However, the genetic underpinnings, as well as the scale and magnitude at which this differentiation occurs in marine habitats are not well understood. We investigated the patterns and degree of genomic heterogeneity in threespine sticklebacks (Gasterosteus aculeatus) by assessing genetic variability in 20 nongenic and 20 genic (associated with genes important for freshwater adaptation) microsatellite loci in samples collected from 38 locations spanning the entire Baltic Sea coast to the North Sea boundary. Population divergence (F(ST) ≈ 0.026) and structuring (five genetic clusters) was significantly more pronounced in the genic as compared to nongenic markers (F(ST) ≈ 0.008; no genetic clusters). Patterns of divergence in the genic markers--45% of which were identified as outliers--correlated with local differences in salinity. Yet, a strong positive correlation between divergence in genic and nongenic markers, and their association with environmental factors suggests that adaptive divergence is reducing gene flow across the genome. Apart from providing a clear demonstration of heterogeneous genomic patterns of differentiation in a marine species, the results are indicative of adaptive population structuring across the relatively young Baltic Sea in spite of ample opportunities for gene flow.
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Affiliation(s)
- Jacquelin DeFaveri
- Ecological Genetics Research Unit, Department of Biosciences, University of Helsinki, PO Box 65, FI 00014, Finland.
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Kitano J, Yoshida K, Suzuki Y. RNA sequencing reveals small RNAs differentially expressed between incipient Japanese threespine sticklebacks. BMC Genomics 2013; 14:214. [PMID: 23547919 PMCID: PMC3637797 DOI: 10.1186/1471-2164-14-214] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2012] [Accepted: 03/20/2013] [Indexed: 01/01/2023] Open
Abstract
Background Non-coding small RNAs, ranging from 20 to 30 nucleotides in length, mediate the regulation of gene expression and play important roles in many biological processes. One class of small RNAs, microRNAs (miRNAs), are highly conserved across taxa and mediate the regulation of the chromatin state and the post-transcriptional regulation of messenger RNA (mRNA). Another class of small RNAs is the Piwi-interacting RNAs, which play important roles in the silencing of transposons and other functional genes. Although the biological functions of the different small RNAs have been elucidated in several laboratory animals, little is known regarding naturally occurring variation in small RNA transcriptomes among closely related species. Results We employed next-generation sequencing technology to compare the expression profiles of brain small RNAs between sympatric species of the Japanese threespine stickleback (Gasterosteus aculeatus). We identified several small RNAs that were differentially expressed between sympatric Pacific Ocean and Japan Sea sticklebacks. Potential targets of several small RNAs were identified as repetitive sequences. Female-biased miRNA expression from the old X chromosome was also observed, and it was attributed to the degeneration of the Y chromosome. Conclusions Our results suggest that expression patterns of small RNA can differ between incipient species and may be a potential mechanism underlying differential mRNA expression and transposon activity.
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Affiliation(s)
- Jun Kitano
- Ecological Genetics Laboratory, National Institute of Genetics, Yata 1111, Mishima, Shizuoka, Japan.
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