1
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Shaw DE, Naftaly AS, White MA. Positive Selection Drives cis-regulatory Evolution Across the Threespine Stickleback Y Chromosome. Mol Biol Evol 2024; 41:msae020. [PMID: 38306314 PMCID: PMC10899008 DOI: 10.1093/molbev/msae020] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2023] [Revised: 12/31/2023] [Accepted: 01/24/2024] [Indexed: 02/04/2024] Open
Abstract
Allele-specific gene expression evolves rapidly on heteromorphic sex chromosomes. Over time, the accumulation of mutations on the Y chromosome leads to widespread loss of gametolog expression, relative to the X chromosome. It remains unclear if expression evolution on degrading Y chromosomes is primarily driven by mutations that accumulate through processes of selective interference, or if positive selection can also favor the down-regulation of coding regions on the Y chromosome that contain deleterious mutations. Identifying the relative rates of cis-regulatory sequence evolution across Y chromosomes has been challenging due to the limited number of reference assemblies. The threespine stickleback (Gasterosteus aculeatus) Y chromosome is an excellent model to identify how regulatory mutations accumulate on Y chromosomes due to its intermediate state of divergence from the X chromosome. A large number of Y-linked gametologs still exist across 3 differently aged evolutionary strata to test these hypotheses. We found that putative enhancer regions on the Y chromosome exhibited elevated substitution rates and decreased polymorphism when compared to nonfunctional sites, like intergenic regions and synonymous sites. This suggests that many cis-regulatory regions are under positive selection on the Y chromosome. This divergence was correlated with X-biased gametolog expression, indicating the loss of expression from the Y chromosome may be favored by selection. Our findings provide evidence that Y-linked cis-regulatory regions exhibit signs of positive selection quickly after the suppression of recombination and allow comparisons with recent theoretical models that suggest the rapid divergence of regulatory regions may be favored to mask deleterious mutations on the Y chromosome.
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Affiliation(s)
- Daniel E Shaw
- Department of Genetics, University of Georgia, Athens, GA 30602, USA
| | | | - Michael A White
- Department of Genetics, University of Georgia, Athens, GA 30602, USA
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2
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Bertram J, Fulton B, Tourigny JP, Peña-Garcia Y, Moyle LC, Hahn MW. CAGEE: Computational Analysis of Gene Expression Evolution. Mol Biol Evol 2023; 40:msad106. [PMID: 37158385 PMCID: PMC10195155 DOI: 10.1093/molbev/msad106] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2022] [Revised: 04/26/2023] [Accepted: 05/01/2023] [Indexed: 05/10/2023] Open
Abstract
Despite the increasing abundance of whole transcriptome data, few methods are available to analyze global gene expression across phylogenies. Here, we present a new software package (Computational Analysis of Gene Expression Evolution [CAGEE]) for inferring patterns of increases and decreases in gene expression across a phylogenetic tree, as well as the rate at which these changes occur. In contrast to previous methods that treat each gene independently, CAGEE can calculate genome-wide rates of gene expression, along with ancestral states for each gene. The statistical approach developed here makes it possible to infer lineage-specific shifts in rates of evolution across the genome, in addition to possible differences in rates among multiple tissues sampled from the same species. We demonstrate the accuracy and robustness of our method on simulated data and apply it to a data set of ovule gene expression collected from multiple self-compatible and self-incompatible species in the genus Solanum to test hypotheses about the evolutionary forces acting during mating system shifts. These comparisons allow us to highlight the power of CAGEE, demonstrating its utility for use in any empirical system and for the analysis of most morphological traits. Our software is available at https://github.com/hahnlab/CAGEE/.
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Affiliation(s)
- Jason Bertram
- Department of Biology, Indiana University, Bloomington, IN
- Department of Mathematics, Western University, London, ON, Canada
| | - Ben Fulton
- Department of Biology, Indiana University, Bloomington, IN
- University Information Technology Services, Indiana University, Bloomington, IN
| | - Jason P Tourigny
- Department of Biology, Indiana University, Bloomington, IN
- Department of Computer Science, Indiana University, Bloomington, IN
| | | | - Leonie C Moyle
- Department of Biology, Indiana University, Bloomington, IN
| | - Matthew W Hahn
- Department of Biology, Indiana University, Bloomington, IN
- Department of Computer Science, Indiana University, Bloomington, IN
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3
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Bennett-Keki S, Fowler EK, Folkes L, Moxon S, Chapman T. Sex-biased gene expression in nutrient-sensing pathways. Proc Biol Sci 2023; 290:20222086. [PMID: 36883280 PMCID: PMC9993052 DOI: 10.1098/rspb.2022.2086] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/09/2023] Open
Abstract
Differences in lifespan between males and females are found across many taxa and may be determined, at least in part, by differential responses to diet. Here we tested the hypothesis that the higher dietary sensitivity of female lifespan is mediated by higher and more dynamic expression in nutrient-sensing pathways in females. We first reanalysed existing RNA-seq data, focusing on 17 nutrient-sensing genes with reported lifespan effects. This revealed, consistent with the hypothesis, a dominant pattern of female-biased gene expression, and among sex-biased genes there tended to be a loss of female-bias after mating. We then tested directly the expression of these 17 nutrient-sensing genes in wild-type third instar larvae, once-mated 5- and 16-day-old adults. This confirmed sex-biased gene expression and showed that it was generally absent in larvae, but frequent and stable in adults. Overall, the findings suggest a proximate explanation for the sensitivity of female lifespan to dietary manipulations. We suggest that the contrasting selective pressures to which males and females are subject create differing nutritional demands and requirements, resulting in sex differences in lifespan. This underscores the potential importance of the health impacts of sex-specific dietary responses.
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Affiliation(s)
- Suzanne Bennett-Keki
- School of Biological Sciences, University of East Anglia, Norwich Research Park, Norwich NR4 7TJ, UK
| | - Emily K. Fowler
- School of Biological Sciences, University of East Anglia, Norwich Research Park, Norwich NR4 7TJ, UK
| | - Leighton Folkes
- School of Biological Sciences, University of East Anglia, Norwich Research Park, Norwich NR4 7TJ, UK
| | - Simon Moxon
- School of Biological Sciences, University of East Anglia, Norwich Research Park, Norwich NR4 7TJ, UK
| | - Tracey Chapman
- School of Biological Sciences, University of East Anglia, Norwich Research Park, Norwich NR4 7TJ, UK
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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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Functional Diversity and Evolution of the Drosophila Sperm Proteome. Mol Cell Proteomics 2022; 21:100281. [PMID: 35985624 PMCID: PMC9494239 DOI: 10.1016/j.mcpro.2022.100281] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2022] [Revised: 07/28/2022] [Accepted: 08/08/2022] [Indexed: 01/18/2023] Open
Abstract
Spermatozoa are central to fertilization and the evolutionary fitness of sexually reproducing organisms. As such, a deeper understanding of sperm proteomes (and associated reproductive tissues) has proven critical to the advancement of the fields of sexual selection and reproductive biology. Due to their extraordinary complexity, proteome depth-of-coverage is dependent on advancements in technology and related bioinformatics, both of which have made significant advancements in the decade since the last Drosophila sperm proteome was published. Here, we provide an updated version of the Drosophila melanogaster sperm proteome (DmSP3) using improved separation and detection methods and an updated genome annotation. Combined with previous versions of the sperm proteome, the DmSP3 contains a total of 3176 proteins, and we provide the first label-free quantitation of the sperm proteome for 2125 proteins. The top 20 most abundant proteins included the structural elements α- and β-tubulins and sperm leucyl-aminopeptidases. Both gene content and protein abundance were significantly reduced on the X chromosome, consistent with prior genomic studies of X chromosome evolution. We identified 9 of the 16 Y-linked proteins, including known testis-specific male fertility factors. We also identified almost one-half of known Drosophila ribosomal proteins in the DmSP3. The role of this subset of ribosomal proteins in sperm is unknown. Surprisingly, our expanded sperm proteome also identified 122 seminal fluid proteins (Sfps), proteins originally identified in the accessory glands. We show that a significant fraction of 'sperm-associated Sfps' are recalcitrant to concentrated salt and detergent treatments, suggesting this subclass of Sfps are expressed in testes and may have additional functions in sperm, per se. Overall, our results add to a growing landscape of both sperm and seminal fluid protein biology and in particular provides quantitative evidence at the protein level for prior findings supporting the meiotic sex-chromosome inactivation model for male-specific gene and X chromosome evolution.
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6
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Meisel RP, Asgari D, Schlamp F, Unckless RL. Induction and inhibition of Drosophila X chromosome gene expression are both impeded by the dosage compensation complex. G3 (BETHESDA, MD.) 2022; 12:6632659. [PMID: 35792851 PMCID: PMC9434221 DOI: 10.1093/g3journal/jkac165] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/28/2022] [Accepted: 06/16/2022] [Indexed: 12/24/2022]
Abstract
Sex chromosomes frequently differ from the autosomes in the frequencies of genes with sexually dimorphic or tissue-specific expression. Multiple hypotheses have been put forth to explain the unique gene content of the X chromosome, including selection against male-beneficial X-linked alleles, expression limits imposed by the haploid dosage of the X in males, and interference by the dosage compensation complex on expression in males. Here, we investigate these hypotheses by examining differential gene expression in Drosophila melanogaster following several treatments that have widespread transcriptomic effects: bacterial infection, viral infection, and abiotic stress. We found that genes that are induced (upregulated) by these biotic and abiotic treatments are frequently under-represented on the X chromosome, but so are those that are repressed (downregulated) following treatment. We further show that whether a gene is bound by the dosage compensation complex in males can largely explain the paucity of both up- and downregulated genes on the X chromosome. Specifically, genes that are bound by the dosage compensation complex, or close to a dosage compensation complex high-affinity site, are unlikely to be up- or downregulated after treatment. This relationship, however, could partially be explained by a correlation between differential expression and breadth of expression across tissues. Nonetheless, our results suggest that dosage compensation complex binding, or the associated chromatin modifications, inhibit both up- and downregulation of X chromosome gene expression within specific contexts, including tissue-specific expression. We propose multiple possible mechanisms of action for the effect, including a role of Males absent on the first, a component of the dosage compensation complex, as a dampener of gene expression variance in both males and females. This effect could explain why the Drosophila X chromosome is depauperate in genes with tissue-specific or induced expression, while the mammalian X has an excess of genes with tissue-specific expression.
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Affiliation(s)
- Richard P Meisel
- Department of Biology and Biochemistry, University of Houston, 3455 Cullen Blvd, Houston, TX 77204-5001, USA
| | - Danial Asgari
- Department of Biology and Biochemistry, University of Houston, 3455 Cullen Blvd, Houston, TX 77204-5001, USA
| | - Florencia Schlamp
- Department of Medicine, NYU Grossman School of Medicine, 435 E 30th St, New York, NY 10016, USA
| | - Robert L Unckless
- Department of Molecular Biosciences, University of Kansas, 4055 Haworth Hall, 1200 Sunnyside Avenue, Lawrence, KS 66045, USA
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7
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The evolution of gene regulation on sex chromosomes. Trends Genet 2022; 38:844-855. [DOI: 10.1016/j.tig.2022.04.004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2021] [Revised: 04/07/2022] [Accepted: 04/11/2022] [Indexed: 11/20/2022]
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8
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Gueno J, Borg M, Bourdareau S, Cossard G, Godfroy O, Lipinska A, Tirichine L, Cock J, Coelho S. Chromatin landscape associated with sexual differentiation in a UV sex determination system. Nucleic Acids Res 2022; 50:3307-3322. [PMID: 35253891 PMCID: PMC8989524 DOI: 10.1093/nar/gkac145] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2021] [Revised: 02/15/2022] [Accepted: 03/04/2022] [Indexed: 12/12/2022] Open
Abstract
In many eukaryotes, such as dioicous mosses and many algae, sex is determined by UV sex chromosomes and is expressed during the haploid phase of the life cycle. In these species, the male and female developmental programs are initiated by the presence of the U- or V-specific regions of the sex chromosomes but, as in XY and ZW systems, sexual differentiation is largely driven by autosomal sex-biased gene expression. The mechanisms underlying the regulation of sex-biased expression of genes during sexual differentiation remain elusive. Here, we investigated the extent and nature of epigenomic changes associated with UV sexual differentiation in the brown alga Ectocarpus, a model UV system. Six histone modifications were quantified in near-isogenic lines, leading to the identification of 16 chromatin signatures across the genome. Chromatin signatures correlated with levels of gene expression and histone PTMs changes in males versus females occurred preferentially at genes involved in sex-specific pathways. Despite the absence of chromosome scale dosage compensation and the fact that UV sex chromosomes recombine across most of their length, the chromatin landscape of these chromosomes was remarkably different to that of autosomes. Hotspots of evolutionary young genes in the pseudoautosomal regions appear to drive the exceptional chromatin features of UV sex chromosomes.
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Affiliation(s)
- Josselin Gueno
- Sorbonne Université, UPMC Univ Paris 06, CNRS, UMR 8227, Integrative Biology of Marine Models, Station Biologique de Roscoff, CS 90074, F-29688 Roscoff, France
| | - Michael Borg
- Department of Algal Development and Evolution, Max Planck Institute for Biology Tübingen72076, Tübingen, Germany
| | - Simon Bourdareau
- Sorbonne Université, UPMC Univ Paris 06, CNRS, UMR 8227, Integrative Biology of Marine Models, Station Biologique de Roscoff, CS 90074, F-29688 Roscoff, France
| | - Guillaume Cossard
- Sorbonne Université, UPMC Univ Paris 06, CNRS, UMR 8227, Integrative Biology of Marine Models, Station Biologique de Roscoff, CS 90074, F-29688 Roscoff, France
| | - Olivier Godfroy
- Sorbonne Université, UPMC Univ Paris 06, CNRS, UMR 8227, Integrative Biology of Marine Models, Station Biologique de Roscoff, CS 90074, F-29688 Roscoff, France
| | - Agnieszka Lipinska
- Sorbonne Université, UPMC Univ Paris 06, CNRS, UMR 8227, Integrative Biology of Marine Models, Station Biologique de Roscoff, CS 90074, F-29688 Roscoff, France
- Department of Algal Development and Evolution, Max Planck Institute for Biology Tübingen72076, Tübingen, Germany
| | - Leila Tirichine
- Nantes Universite, CNRS, US2B, UMR 6286, F-44000, Nantes, France
| | - J Mark Cock
- Sorbonne Université, UPMC Univ Paris 06, CNRS, 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, UMR 8227, Integrative Biology of Marine Models, Station Biologique de Roscoff, CS 90074, F-29688 Roscoff, France
- Department of Algal Development and Evolution, Max Planck Institute for Biology Tübingen72076, Tübingen, Germany
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9
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Cridland JM, Majane AC, Zhao L, Begun DJ. Population biology of accessory gland-expressed de novo genes in Drosophila melanogaster. Genetics 2022; 220:iyab207. [PMID: 34791207 PMCID: PMC8733444 DOI: 10.1093/genetics/iyab207] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2021] [Accepted: 11/08/2021] [Indexed: 12/20/2022] Open
Abstract
Early work on de novo gene discovery in Drosophila was consistent with the idea that many such genes have male-biased patterns of expression, including a large number expressed in the testis. However, there has been little formal analysis of variation in the abundance and properties of de novo genes expressed in different tissues. Here, we investigate the population biology of recently evolved de novo genes expressed in the Drosophila melanogaster accessory gland, a somatic male tissue that plays an important role in male and female fertility and the post mating response of females, using the same collection of inbred lines used previously to identify testis-expressed de novo genes, thus allowing for direct cross tissue comparisons of these genes in two tissues of male reproduction. Using RNA-seq data, we identify candidate de novo genes located in annotated intergenic and intronic sequence and determine the properties of these genes including chromosomal location, expression, abundance, and coding capacity. Generally, we find major differences between the tissues in terms of gene abundance and expression, though other properties such as transcript length and chromosomal distribution are more similar. We also explore differences between regulatory mechanisms of de novo genes in the two tissues and how such differences may interact with selection to produce differences in D. melanogaster de novo genes expressed in the two tissues.
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Affiliation(s)
- Julie M Cridland
- Department of Evolution and Ecology, University of California, Davis, Davis, CA 95616, USA
| | - Alex C Majane
- Department of Evolution and Ecology, University of California, Davis, Davis, CA 95616, USA
| | - Li Zhao
- Laboratory of Evolutionary Genetics and Genomics, The Rockefeller University, New York, NY 10065, USA
| | - David J Begun
- Department of Evolution and Ecology, University of California, Davis, Davis, CA 95616, USA
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10
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Dechaud C, Miyake S, Martinez-Bengochea A, Schartl M, Volff JN, Naville M. Clustering of Sex-Biased Genes and Transposable Elements in the Genome of the Medaka Fish Oryzias latipes. Genome Biol Evol 2021; 13:6384576. [PMID: 34623422 PMCID: PMC8633743 DOI: 10.1093/gbe/evab230] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/04/2021] [Indexed: 12/17/2022] Open
Abstract
Although genes with similar expression patterns are sometimes found in the same genomic regions, almost nothing is known about the relative organization in genomes of genes and transposable elements (TEs), which might influence each other at the regulatory level. In this study, we used transcriptomic data from male and female gonads of the Japanese medaka Oryzias latipes to define sexually biased genes and TEs and analyze their relative genomic localization. We identified 20,588 genes expressed in the adult gonads of O. latipes. Around 39% of these genes are differentially expressed between male and female gonads. We further analyzed the expression of TEs using the program SQuIRE and showed that more TE copies are overexpressed in testis than in ovaries (36% vs. 10%, respectively). We then developed a method to detect genomic regions enriched in testis- or ovary-biased genes. This revealed that sex-biased genes and TEs are not randomly distributed in the genome and a part of them form clusters with the same expression bias. We also found a correlation of expression between TE copies and their closest genes, which increases with decreasing intervening distance. Such a genomic organization suggests either that TEs hijack the regulatory sequences of neighboring sexual genes, allowing their expression in germ line cells and consequently new insertions to be transmitted to the next generation, or that TEs are involved in the regulation of sexual genes, and might therefore through their mobility participate in the rewiring of sex regulatory networks.
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Affiliation(s)
- Corentin Dechaud
- Institut de Genomique Fonctionnelle de Lyon, Univ Lyon, CNRS UMR 5242, Ecole Normale Superieure de Lyon, Universite Claude Bernard Lyon 1, Lyon, France
| | - Sho Miyake
- Institut de Genomique Fonctionnelle de Lyon, Univ Lyon, CNRS UMR 5242, Ecole Normale Superieure de Lyon, Universite Claude Bernard Lyon 1, Lyon, France
| | | | - Manfred Schartl
- Entwicklungsbiochemie, Biozentrum, Universität Würzburg, Würzburg, Germany.,Department of Chemistry and Biochemistry, The Xiphophorus Genetic Stock Center, Texas State University, San Marcos, Texas, USA
| | - Jean-Nicolas Volff
- Institut de Genomique Fonctionnelle de Lyon, Univ Lyon, CNRS UMR 5242, Ecole Normale Superieure de Lyon, Universite Claude Bernard Lyon 1, Lyon, France
| | - Magali Naville
- Institut de Genomique Fonctionnelle de Lyon, Univ Lyon, CNRS UMR 5242, Ecole Normale Superieure de Lyon, Universite Claude Bernard Lyon 1, Lyon, France
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11
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Ruzicka F, Connallon T, Reuter M. Sex differences in deleterious mutational effects in Drosophila melanogaster: combining quantitative and population genetic insights. Genetics 2021; 219:6362879. [PMID: 34740242 DOI: 10.1093/genetics/iyab143] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2021] [Accepted: 08/25/2021] [Indexed: 11/14/2022] Open
Abstract
Fitness effects of deleterious mutations can differ between females and males due to: (i) sex differences in the strength of purifying selection; and (ii) sex differences in ploidy. Although sex differences in fitness effects have important broader implications (e.g., for the evolution of sex and lifespan), few studies have quantified their scope. Those that have belong to one of two distinct empirical traditions: (i) quantitative genetics, which focusses on multi-locus genetic variances in each sex, but is largely agnostic about their genetic basis; and (ii) molecular population genetics, which focusses on comparing autosomal and X-linked polymorphism, but is poorly suited for inferring contemporary sex differences. Here, we combine both traditions to present a comprehensive analysis of female and male adult reproductive fitness among 202 outbred, laboratory-adapted, hemiclonal genomes of Drosophila melanogaster. While we find no clear evidence for sex differences in the strength of purifying selection, sex differences in ploidy generate multiple signals of enhanced purifying selection for X-linked loci. These signals are present in quantitative genetic metrics-i.e., a disproportionate contribution of the X to male (but not female) fitness variation-and population genetic metrics-i.e., steeper regressions of an allele's average fitness effect on its frequency, and proportionally less nonsynonymous polymorphism on the X than autosomes. Fitting our data to models for both sets of metrics, we infer that deleterious alleles are partially recessive. Given the often-large gap between quantitative and population genetic estimates of evolutionary parameters, our study showcases the benefits of combining genomic and fitness data when estimating such parameters.
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Affiliation(s)
- Filip Ruzicka
- School of Biological Sciences and Centre for Geometric Biology, Monash University, Clayton 3800, VIC, Australia.,Department of Genetics, Evolution and Environment, University College London, London WC1E 6BT, UK
| | - Tim Connallon
- School of Biological Sciences and Centre for Geometric Biology, Monash University, Clayton 3800, VIC, Australia
| | - Max Reuter
- Department of Genetics, Evolution and Environment, University College London, London WC1E 6BT, UK.,Centre for Life's Origins and Evolution, University College London, London WC1E 6BT, UK
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12
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Mongue AJ, Hansen ME, Walters JR. Support for faster and more adaptive Z chromosome evolution in two divergent lepidopteran lineages. Evolution 2021; 76:332-345. [PMID: 34463346 PMCID: PMC9291949 DOI: 10.1111/evo.14341] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2021] [Revised: 07/21/2021] [Accepted: 08/06/2021] [Indexed: 12/14/2022]
Abstract
The rateof divergence for Z or X chromosomes is usually observed to be greater than autosomes, but the proposed evolutionary causes for this pattern vary, as do empirical results from diverse taxa. Even among moths and butterflies (Lepidoptera), which generally share a single-origin Z chromosome, the handful of available studies give mixed support for faster or more adaptive evolution of the Z chromosome, depending on the species assayed. Here, we examine the molecular evolution of Z chromosomes in two additional lepidopteran species: the Carolina sphinx moth and the monarch butterfly, the latter of which possesses a recent chromosomal fusion yielding a segment of newly Z-linked DNA. We find evidence for both faster and more adaptive Z chromosome evolution in both species, although this effect is strongest in the neo-Z portion of the monarch sex chromosome. The neo-Z is less male-biased than expected of a Z chromosome, and unbiased and female-biased genes drive the signal for adaptive evolution here. Together these results suggest that male-biased gene accumulation and haploid selection have opposing effects on long-term rates of adaptation and may help explain the discrepancies in previous findings as well as the repeated evolution of neo-sex chromosomes in Lepidoptera.
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Affiliation(s)
- Andrew J Mongue
- Department of Ecology and Evolutionary Biology, University of Kansas, Lawrence, Kansas, 66045.,Institute of Evolutionary Biology, University of Edinburgh, Edinburgh, EH93FL, United Kingdom
| | - Megan E Hansen
- Department of Ecology and Evolutionary Biology, University of Kansas, Lawrence, Kansas, 66045
| | - James R Walters
- Department of Ecology and Evolutionary Biology, University of Kansas, Lawrence, Kansas, 66045
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13
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He L, Jia KH, Zhang RG, Wang Y, Shi TL, Li ZC, Zeng SW, Cai XJ, Wagner ND, Hörandl E, Muyle A, Yang K, Charlesworth D, Mao JF. Chromosome-scale assembly of the genome of Salix dunnii reveals a male-heterogametic sex determination system on chromosome 7. Mol Ecol Resour 2021; 21:1966-1982. [PMID: 33609314 PMCID: PMC8359994 DOI: 10.1111/1755-0998.13362] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2020] [Revised: 02/10/2021] [Accepted: 02/16/2021] [Indexed: 12/23/2022]
Abstract
Sex determination systems in plants can involve either female or male heterogamety (ZW or XY, respectively). Here we used Illumina short reads, Oxford Nanopore Technologies (ONT) long reads and Hi-C reads to assemble the first chromosome-scale genome of a female willow tree (Salix dunnii), and to predict genes using transcriptome sequences and available databases. The final genome sequence of 328 Mb in total was assembled in 29 scaffolds, and includes 31,501 predicted genes. Analyses of short-read sequence data that included female and male plants suggested a male heterogametic sex-determining factor on chromosome 7, implying that, unlike the female heterogamety of most species in the genus Salix, male heterogamety evolved in the subgenus Salix. The S. dunnii sex-linked region occupies about 3.21 Mb of chromosome 7 in females (representing its position in the X chromosome), probably within a pericentromeric region. Our data suggest that this region is enriched for transposable element insertions, and about one-third of its 124 protein-coding genes were gained via duplications from other genome regions. We detect purifying selection on the genes that were ancestrally present in the region, though some have been lost. Transcriptome data from female and male individuals show more male- than female-biased genes in catkin and leaf tissues, and indicate enrichment for male-biased genes in the pseudo-autosomal regions. Our study provides valuable genomic resources for further studies of sex-determining regions in the family Salicaceae, and sex chromosome evolution.
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Affiliation(s)
- Li He
- Beijing Advanced Innovation Center for Tree Breeding by Molecular Design, National Engineering Laboratory for Tree Breeding, Key Laboratory of Genetics and Breeding in Forest Trees and Ornamental Plants, Ministry of Education, College of Biological Sciences and Technology, Beijing Forestry University, Beijing, China.,College of Forestry, Fujian Agriculture and Forestry University, Fuzhou, China
| | - Kai-Hua Jia
- Beijing Advanced Innovation Center for Tree Breeding by Molecular Design, National Engineering Laboratory for Tree Breeding, Key Laboratory of Genetics and Breeding in Forest Trees and Ornamental Plants, Ministry of Education, College of Biological Sciences and Technology, Beijing Forestry University, Beijing, China
| | - Ren-Gang Zhang
- Ori (Shandong) Gene Science and Technology Co., Ltd, Weifang, China
| | - Yuan Wang
- College of Forestry, Fujian Agriculture and Forestry University, Fuzhou, China
| | - Tian-Le Shi
- Beijing Advanced Innovation Center for Tree Breeding by Molecular Design, National Engineering Laboratory for Tree Breeding, Key Laboratory of Genetics and Breeding in Forest Trees and Ornamental Plants, Ministry of Education, College of Biological Sciences and Technology, Beijing Forestry University, Beijing, China
| | - Zhi-Chao Li
- Beijing Advanced Innovation Center for Tree Breeding by Molecular Design, National Engineering Laboratory for Tree Breeding, Key Laboratory of Genetics and Breeding in Forest Trees and Ornamental Plants, Ministry of Education, College of Biological Sciences and Technology, Beijing Forestry University, Beijing, China
| | - Si-Wen Zeng
- College of Forestry, Fujian Agriculture and Forestry University, Fuzhou, China
| | - Xin-Jie Cai
- College of Forestry, Fujian Agriculture and Forestry University, Fuzhou, China
| | - Natascha Dorothea Wagner
- Department of Systematics, Biodiversity and Evolution of Plants (with Herbarium), University of Goettingen, Göttingen, Germany
| | - Elvira Hörandl
- Department of Systematics, Biodiversity and Evolution of Plants (with Herbarium), University of Goettingen, Göttingen, Germany
| | - Aline Muyle
- Department of Ecology and Evolutionary Biology, University of California Irvine, Irvine, CA, USA
| | - Ke Yang
- Institute of Evolutionary Biology, School of Biological Sciences, University of Edinburgh, Edinburgh, UK
| | - Deborah Charlesworth
- Institute of Evolutionary Biology, School of Biological Sciences, University of Edinburgh, Edinburgh, UK
| | - Jian-Feng Mao
- Beijing Advanced Innovation Center for Tree Breeding by Molecular Design, National Engineering Laboratory for Tree Breeding, Key Laboratory of Genetics and Breeding in Forest Trees and Ornamental Plants, Ministry of Education, College of Biological Sciences and Technology, Beijing Forestry University, Beijing, China
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14
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Duan Y, Dou S, Porath HT, Huang J, Eisenberg E, Lu J. A-to-I RNA editing in honeybees shows signals of adaptation and convergent evolution. iScience 2021; 24:101983. [PMID: 33458624 PMCID: PMC7797907 DOI: 10.1016/j.isci.2020.101983] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2020] [Revised: 11/18/2020] [Accepted: 12/17/2020] [Indexed: 12/27/2022] Open
Abstract
Social insects exhibit extensive phenotypic diversities among the genetically similar individuals, suggesting a role for the epigenetic regulations beyond the genome level. The ADAR-mediated adenosine-to-inosine (A-to-I) RNA editing, an evolutionarily conserved mechanism, facilitates adaptive evolution by expanding proteomic diversities. Here, we characterize the A-to-I RNA editome of honeybees (Apis mellifera), identifying 407 high-confidence A-to-I editing sites. Editing is most abundant in the heads and shows signatures for positive selection. Editing behavior differs between foragers and nurses, suggesting a role for editing in caste differentiation. Although only five sites are conserved between bees and flies, an unexpectedly large number of genes exhibit editing in both species, albeit at different locations, including the nonsynonymous auto-editing of Adar. This convergent evolution, where the same target genes independently acquire recoding events in distant diverged clades, together with the signals of adaptation observed in honeybees alone, further supports the notion of recoding being adaptive. Nonsynonymous editing sites in honeybees were under positive selection Differential editing may contribute to the phenotypic diversity between sub-castes Target genes acquire editing in different clades, suggesting convergent evolution
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Affiliation(s)
- Yuange Duan
- State Key Laboratory of Protein and Plant Gene Research, Center for Bioinformatics, School of Life Sciences, Peking University, Beijing, 100871, China.,Academy for Advanced Interdisciplinary Studies, Peking University, Beijing, 100871, China
| | - Shengqian Dou
- State Key Laboratory of Protein and Plant Gene Research, Center for Bioinformatics, School of Life Sciences, Peking University, Beijing, 100871, China
| | - Hagit T Porath
- The Mina and Everard Goodman Faculty of Life Sciences, Bar Ilan University, Ramat-Gan 52900, Israel
| | - Jiaxing Huang
- Key Laboratory for Insect-Pollinator Biology of the Ministry of Agriculture and Rural Affairs, Institute of Apicultural Research, Chinese Academy of Agricultural Sciences, Beijing, 100093, China
| | - Eli Eisenberg
- Raymond and Beverly Sackler School of Physics and Astronomy and Sagol School of Neuroscience, Tel Aviv University, Tel Aviv 6997801, Israel
| | - Jian Lu
- State Key Laboratory of Protein and Plant Gene Research, Center for Bioinformatics, School of Life Sciences, Peking University, Beijing, 100871, China
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15
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Belyi A, Argyridou E, Parsch J. The Influence of Chromosomal Environment on X-Linked Gene Expression in Drosophila melanogaster. Genome Biol Evol 2020; 12:2391-2402. [PMID: 33104185 PMCID: PMC7719225 DOI: 10.1093/gbe/evaa227] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/21/2020] [Indexed: 12/14/2022] Open
Abstract
Sex chromosomes often differ from autosomes with respect to their gene expression and regulation. In Drosophila melanogaster, X-linked genes are dosage compensated by having their expression upregulated in the male soma, a process mediated by the X-chromosome-specific binding of the dosage compensation complex (DCC). Previous studies of X-linked gene expression found a negative correlation between a gene’s male-to-female expression ratio and its distance to the nearest DCC binding site in somatic tissues, including head and brain, which suggests that dosage compensation influences sex-biased gene expression. A limitation of the previous studies, however, was that they focused on endogenous X-linked genes and, thus, could not disentangle the effects of chromosomal position from those of gene-specific regulation. To overcome this limitation, we examined the expression of an exogenous reporter gene inserted at many locations spanning the X chromosome. We observed a negative correlation between the male-to-female expression ratio of the reporter gene and its distance to the nearest DCC binding site in somatic tissues, but not in gonads. A reporter gene’s location relative to a DCC binding site had greater influence on its expression than the local regulatory elements of neighboring endogenous genes, suggesting that intra-chromosomal variation in the strength of dosage compensation is a major determinant of sex-biased gene expression. Average levels of sex-biased expression did not differ between head and brain, but there was greater positional effect variation in the brain, which may explain the observed excess of endogenous sex-biased genes located on the X chromosome in this tissue.
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Affiliation(s)
- Aleksei Belyi
- Division of Evolutionary Biology, Faculty of Biology, LMU Munich, Planegg-Martinsried, Germany
| | - Eliza Argyridou
- Division of Evolutionary Biology, Faculty of Biology, LMU Munich, Planegg-Martinsried, Germany
| | - John Parsch
- Division of Evolutionary Biology, Faculty of Biology, LMU Munich, Planegg-Martinsried, Germany
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16
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Meisel RP. Evolution of Sex Determination and Sex Chromosomes: A Novel Alternative Paradigm. Bioessays 2020; 42:e1900212. [DOI: 10.1002/bies.201900212] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2019] [Revised: 05/11/2020] [Indexed: 12/17/2022]
Affiliation(s)
- Richard P. Meisel
- Department of Biology and Biochemistry University of Houston 3455 Cullen Blvd Houston TX 77204‐5001 USA
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17
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Shi MW, Zhang NA, Shi CP, Liu CJ, Luo ZH, Wang DY, Guo AY, Chen ZX. SAGD: a comprehensive sex-associated gene database from transcriptomes. Nucleic Acids Res 2020; 47:D835-D840. [PMID: 30380119 PMCID: PMC6323940 DOI: 10.1093/nar/gky1040] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2018] [Accepted: 10/16/2018] [Indexed: 12/19/2022] Open
Abstract
Many animal species present sex differences. Sex-associated genes (SAGs), which have female-biased or male-biased expression, have major influences on the remarkable sex differences in important traits such as growth, reproduction, disease resistance and behaviors. However, the SAGs resulting in the vast majority of phenotypic sex differences are still unknown. To provide a useful resource for the functional study of SAGs, we manually curated public RNA-seq datasets with paired female and male biological replicates from the same condition and systematically re-analyzed the datasets using standardized methods. We identified 27,793 female-biased SAGs and 64,043 male-biased SAGs from 2,828 samples of 21 species, including human, chimpanzee, macaque, mouse, rat, cow, horse, chicken, zebrafish, seven fly species and five worm species. All these data were cataloged into SAGD, a user-friendly database of SAGs (http://bioinfo.life.hust.edu.cn/SAGD) where users can browse SAGs by gene, species, drug and dataset. In SAGD, the expression, annotation, targeting drugs, homologs, ontology and related RNA-seq datasets of SAGs are provided to help researchers to explore their functions and potential applications in agriculture and human health.
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Affiliation(s)
- Meng-Wei Shi
- Hubei Key Laboratory of Agricultural Bioinformatics, College of Life Science and Technology, Huazhong Agricultural University, Wuhan, Hubei 430070, PR China
| | - Na-An Zhang
- Hubei Key Laboratory of Agricultural Bioinformatics, College of Life Science and Technology, Huazhong Agricultural University, Wuhan, Hubei 430070, PR China
| | - Chuan-Ping Shi
- Hubei Key Laboratory of Agricultural Bioinformatics, College of Life Science and Technology, Huazhong Agricultural University, Wuhan, Hubei 430070, PR China
| | - Chun-Jie Liu
- Department of Bioinformatics and Systems Biology, Hubei Bioinformatics & Molecular Imaging Key Laboratory, Key Laboratory of Molecular Biophysics of the Ministry of Education, College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan, Hubei 430074, PR China
| | - Zhi-Hui Luo
- Hubei Key Laboratory of Agricultural Bioinformatics, College of Life Science and Technology, Huazhong Agricultural University, Wuhan, Hubei 430070, PR China
| | - Dan-Yang Wang
- Hubei Key Laboratory of Agricultural Bioinformatics, College of Life Science and Technology, Huazhong Agricultural University, Wuhan, Hubei 430070, PR China
| | - An-Yuan Guo
- Department of Bioinformatics and Systems Biology, Hubei Bioinformatics & Molecular Imaging Key Laboratory, Key Laboratory of Molecular Biophysics of the Ministry of Education, College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan, Hubei 430074, PR China
| | - Zhen-Xia Chen
- Hubei Key Laboratory of Agricultural Bioinformatics, College of Life Science and Technology, Huazhong Agricultural University, Wuhan, Hubei 430070, PR China
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18
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Abstract
Sex chromosomes and sex determining genes can evolve fast, with the sex-linked chromosomes often differing between closely related species. Population genetics theory has been developed and tested to explain the rapid evolution of sex chromosomes and sex determination. However, we do not know why the sex chromosomes are divergent in some taxa and conserved in others. Addressing this question requires comparing closely related taxa with conserved and divergent sex chromosomes to identify biological features that could explain these differences. Cytological karyotypes suggest that muscid flies (e.g., house fly) and blow flies are such a taxonomic pair. The sex chromosomes appear to differ across muscid species, whereas they are conserved across blow flies. Despite the cytological evidence, we do not know the extent to which muscid sex chromosomes are independently derived along different evolutionary lineages. To address that question, we used genomic and transcriptomic sequence data to identify young sex chromosomes in two closely related muscid species, horn fly (Haematobia irritans) and stable fly (Stomoxys calcitrans). We provide evidence that the nascent sex chromosomes of horn fly and stable fly were derived independently from each other and from the young sex chromosomes of the closely related house fly (Musca domestica). We present three different scenarios that could have given rise to the sex chromosomes of horn fly and stable fly, and we describe how the scenarios could be distinguished. Distinguishing between these scenarios in future work could identify features of muscid genomes that promote sex chromosome divergence.
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19
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Sigeman H, Ponnikas S, Chauhan P, Dierickx E, Brooke MDL, Hansson B. Repeated sex chromosome evolution in vertebrates supported by expanded avian sex chromosomes. Proc Biol Sci 2019; 286:20192051. [PMID: 31771477 PMCID: PMC6939255 DOI: 10.1098/rspb.2019.2051] [Citation(s) in RCA: 26] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2019] [Accepted: 11/01/2019] [Indexed: 12/28/2022] Open
Abstract
Sex chromosomes have evolved from the same autosomes multiple times across vertebrates, suggesting that selection for recombination suppression has acted repeatedly and independently on certain genetic backgrounds. Here, we perform comparative genomics of a bird clade (larks and their sister lineage; Alaudidae and Panuridae) where multiple autosome-sex chromosome fusions appear to have formed expanded sex chromosomes. We detected the largest known avian sex chromosome (195.3 Mbp) and show that it originates from fusions between parts of four avian chromosomes: Z, 3, 4A and 5. Within these four chromosomes, we found evidence of five evolutionary strata where recombination had been suppressed at different time points, and show that stratum age explained the divergence rate of Z-W gametologs. Next, we analysed chromosome content and found that chromosome 3 was significantly enriched for genes with predicted sex-related functions. Finally, we demonstrate extensive homology to sex chromosomes in other vertebrate lineages: chromosomes Z, 3, 4A and 5 have independently evolved into sex chromosomes in fish (Z), turtles (Z, 5), lizards (Z, 4A), mammals (Z, 4A) and frogs (Z, 3, 4A, 5). Our results provide insights into and support for repeated evolution of sex chromosomes in vertebrates.
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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
| | - Pallavi Chauhan
- Department of Biology, Lund University, Ecology Building, 223 62 Lund, Sweden
| | - Elisa Dierickx
- Department of Zoology, University of Cambridge, Downing Street, Cambridge CB23EJ, UK
| | - M. de L. Brooke
- Department of Zoology, University of Cambridge, Downing Street, Cambridge CB23EJ, UK
| | - Bengt Hansson
- Department of Biology, Lund University, Ecology Building, 223 62 Lund, Sweden
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20
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Vizán-Rico HI, Mayer C, Petersen M, McKenna DD, Zhou X, Gómez-Zurita J. Patterns and Constraints in the Evolution of Sperm Individualization Genes in Insects, with an Emphasis on Beetles. Genes (Basel) 2019; 10:E776. [PMID: 31590243 PMCID: PMC6826512 DOI: 10.3390/genes10100776] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2019] [Revised: 09/20/2019] [Accepted: 10/01/2019] [Indexed: 11/17/2022] Open
Abstract
Gene expression profiles can change dramatically between sexes and sex bias may contribute specific macroevolutionary dynamics for sex-biased genes. However, these dynamics are poorly understood at large evolutionary scales due to the paucity of studies that have assessed orthology and functional homology for sex-biased genes and the pleiotropic effects possibly constraining their evolutionary potential. Here, we explore the correlation of sex-biased expression with macroevolutionary processes that are associated with sex-biased genes, including duplications and accelerated evolutionary rates. Specifically, we examined these traits in a group of 44 genes that orchestrate sperm individualization during spermatogenesis, with both unbiased and sex-biased expression. We studied these genes in the broad evolutionary framework of the Insecta, with a particular focus on beetles (order Coleoptera). We studied data mined from 119 insect genomes, including 6 beetle models, and from 19 additional beetle transcriptomes. For the subset of physically and/or genetically interacting proteins, we also analyzed how their network structure may condition the mode of gene evolution. The collection of genes was highly heterogeneous in duplication status, evolutionary rates, and rate stability, but there was statistical evidence for sex bias correlated with faster evolutionary rates, consistent with theoretical predictions. Faster rates were also correlated with clocklike (insect amino acids) and non-clocklike (beetle nucleotides) substitution patterns in these genes. Statistical associations (higher rates for central nodes) or lack thereof (centrality of duplicated genes) were in contrast to some current evolutionary hypotheses, highlighting the need for more research on these topics.
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Affiliation(s)
- Helena I. Vizán-Rico
- Animal Biodiversity and Evolution, Institute of Evolutionary Biology (CSIC-Universitat Pompeu Fabra), 08003 Barcelona, Spain;
| | - Christoph Mayer
- Center for Molecular Biodiversity Research, Zoological Research Museum Alexander Koenig, 53113 Bonn, Germany; (C.M.); (M.P.)
| | - Malte Petersen
- Center for Molecular Biodiversity Research, Zoological Research Museum Alexander Koenig, 53113 Bonn, Germany; (C.M.); (M.P.)
| | - Duane D. McKenna
- Center for Biodiversity Research, Department of Biological Sciences, University of Memphis, Memphis, TN 38152, USA;
| | - Xin Zhou
- Department of Entomology, College of Plant Protection, China Agricultural University, Beijing 100193, China;
| | - Jesús Gómez-Zurita
- Animal Biodiversity and Evolution, Institute of Evolutionary Biology (CSIC-Universitat Pompeu Fabra), 08003 Barcelona, Spain;
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21
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Son JH, Kohlbrenner T, Heinze S, Beukeboom LW, Bopp D, Meisel RP. Minimal Effects of Proto- Y Chromosomes on House Fly Gene Expression in Spite of Evidence that Selection Maintains Stable Polygenic Sex Determination. Genetics 2019; 213:313-327. [PMID: 31315889 PMCID: PMC6727804 DOI: 10.1534/genetics.119.302441] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2019] [Accepted: 07/10/2019] [Indexed: 02/05/2023] Open
Abstract
Sex determination, the developmental process by which organismal sex is established, evolves fast, often due to changes in the master regulators at the top of the pathway. Additionally, in species with polygenic sex determination, multiple different master regulators segregate as polymorphisms. Understanding the forces that maintain polygenic sex determination can be informative of the factors that drive the evolution of sex determination. The house fly, Musca domestica, is a well-suited model to those ends because natural populations harbor male-determining loci on each of the six chromosomes and a biallelic female determiner. To investigate how natural selection maintains polygenic sex determination in the house fly, we assayed the phenotypic effects of proto-Y chromosomes by performing mRNA-sequencing experiments to measure gene expression in house fly males carrying different proto-Y chromosomes. We find that the proto-Y chromosomes have similar effects as a nonsex-determining autosome. In addition, we created sex-reversed males without any proto-Y chromosomes and they had nearly identical gene expression profiles as genotypic males. Therefore, the proto-Y chromosomes have a minor effect on male gene expression, consistent with previously described minimal X-Y sequence differences. Despite these minimal differences, we find evidence for a disproportionate effect of one proto-Y chromosome on male-biased expression, which could be partially responsible for fitness differences between males with different proto-Y chromosome genotypes. Therefore our results suggest that, if natural selection maintains polygenic sex determination in house fly via gene expression differences, the phenotypes under selection likely depend on a small number of genetic targets.
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Affiliation(s)
- Jae Hak Son
- Department of Biology and Biochemistry, University of Houston, Texas 77204-5001
| | - Tea Kohlbrenner
- Institute of Molecular Life Sciences, University of Zurich, Switzerland CH-8057
| | - Svenia Heinze
- Institute of Molecular Life Sciences, University of Zurich, Switzerland CH-8057
| | - Leo W Beukeboom
- Groningen Institute for Evolutionary Life Sciences, University of Groningen, The Netherlands 9700
| | - Daniel Bopp
- Institute of Molecular Life Sciences, University of Zurich, Switzerland CH-8057
| | - Richard P Meisel
- Department of Biology and Biochemistry, University of Houston, Texas 77204-5001
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22
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Allen SL, Bonduriansky R, Chenoweth SF. Genetic constraints on microevolutionary divergence of sex-biased gene expression. Philos Trans R Soc Lond B Biol Sci 2019; 373:rstb.2017.0427. [PMID: 30150225 DOI: 10.1098/rstb.2017.0427] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/17/2018] [Indexed: 12/18/2022] Open
Abstract
The evolution of sex-specific phenotypes is an important dimension of diversification and local adaptation. The sex-dependent regulation of gene expression is considered a key genomic mechanism facilitating sex-dependent adaptation. In many species, genes with male-biased expression evolve faster in DNA sequence and expression level than genes with female-biased or sexually monomorphic expression. While positive selection may be responsible for rapid DNA sequence evolution, why expression of male-biased genes also evolves rapidly remains unclear. Beyond sex differences in selection, some aspects of the genetic architecture of gene expression could contribute to the rapid evolution of male-biased gene expression. First, male-biased genes might simply have greater standing genetic variance than female-biased genes. Second, male-biased genes could be less constrained by pleiotropy, either within or between sexes. Here, we evaluate these alternative explanations on an intraspecific scale using a series of quantitative genetic experiments conducted on natural variation in male and female gene expression in the fly Drosophila serrata Male-biased genes had significantly higher genetic variance than female-biased genes and were generally more narrowly expressed across tissues, suggesting lower within-individual pleiotropy. However, consistent with stronger constraints due to between-sex pleiotropy, their between-sex genetic correlations, rMF, were higher than for female-biased genes and more strongly negatively associated with sex bias. Using an extensive clinal dataset, we tested whether sex differences in gene expression divergence among populations have been shaped by pleiotropy. Here too, male-biased gene divergence was more strongly associated with between-sex pleiotropy than was female-biased gene divergence. Systematic differences in genetic variance and pleiotropy may be important factors influencing sex-specific adaptation arising through changes in gene expression.This article is part of the theme issue 'Linking local adaptation with the evolution of sex differences'.
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Affiliation(s)
- Scott L Allen
- The School of Biological Sciences, The University of Queensland, St Lucia 4072, Australia
| | - Russell Bonduriansky
- Evolution and Ecology Research Centre and School of Biological, Earth and Environmental Sciences, University of New South Wales, Sydney 2052, New South Wales, Australia
| | - Stephen F Chenoweth
- The School of Biological Sciences, The University of Queensland, St Lucia 4072, Australia
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23
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Cossard GG, Toups MA, Pannell JR. Sexual dimorphism and rapid turnover in gene expression in pre-reproductive seedlings of a dioecious herb. ANNALS OF BOTANY 2019; 123:1119-1131. [PMID: 30289430 PMCID: PMC6612945 DOI: 10.1093/aob/mcy183] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/06/2018] [Accepted: 09/06/2018] [Indexed: 05/06/2023]
Abstract
BACKGROUND AND AIMS Sexual dimorphism in morphology, physiology or life history traits is common in dioecious plants at reproductive maturity, but it is typically inconspicuous or absent in juveniles. Although plants of different sexes probably begin to diverge in gene expression both before their reproduction commences and before dimorphism becomes readily apparent, to our knowledge transcriptome-wide differential gene expression has yet to be demonstrated for any angiosperm species. METHODS The present study documents differences in gene expression in both above- and below-ground tissues of early pre-reproductive individuals of the wind-pollinated dioecious annual herb, Mercurialis annua, which otherwise shows clear sexual dimorphism only at the adult stage. KEY RESULTS Whereas males and females differed in their gene expression at the first leaf stage, sex-biased gene expression peaked just prior to, and after, flowering, as might be expected if sexual dimorphism is partly a response to differential costs of reproduction. Sex-biased genes were over-represented among putative sex-linked genes in M. annua but showed no evidence for more rapid evolution than unbiased genes. CONCLUSIONS Sex-biased gene expression in M. annua occurs as early as the first whorl of leaves is produced, is highly dynamic during plant development and varies substantially between vegetative tissues.
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Affiliation(s)
- Guillaume G Cossard
- Department of Ecology and Evolution, Biophore Building, University of Lausanne, Lausanne, Switzerland
| | - Melissa A Toups
- Department of Ecology and Evolution, Biophore Building, University of Lausanne, Lausanne, Switzerland
- Institute of Science and Technology Austria, Klosterneuburg, Austria
| | - John R Pannell
- Department of Ecology and Evolution, Biophore Building, University of Lausanne, Lausanne, Switzerland
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24
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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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25
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Ågren JA, Munasinghe M, Clark AG. Sexual conflict through mother's curse and father's curse. Theor Popul Biol 2019; 129:9-17. [PMID: 31054851 DOI: 10.1016/j.tpb.2018.12.007] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2018] [Revised: 11/15/2018] [Accepted: 12/27/2018] [Indexed: 12/31/2022]
Abstract
In contrast with autosomes, lineages of sex chromosomes reside for different amounts of time in males and females, and this transmission asymmetry makes them hotspots for sexual conflict. Similarly, the maternal inheritance of the mitochondrial genome (mtDNA) means that mutations that are beneficial in females can spread in a population even if they are deleterious in males, a form of sexual conflict known as Mother's Curse. While both Mother's Curse and sex chromosome induced sexual conflict have been well studied on their own, the interaction between mitochondrial genes and genes on sex chromosomes is poorly understood. Here, we use analytical models and computer simulations to perform a comprehensive examination of how transmission asymmetries of nuclear, mitochondrial, and sex chromosome-linked genes may both cause and resolve sexual conflicts. For example, the accumulation of male-biased Mother's Curse mtDNA mutations will lead to selection in males for compensatory nuclear modifier loci that alleviate the effect. We show how the Y chromosome, being strictly paternally transmitted provides a particularly safe harbor for such modifiers. This analytical framework also allows us to discover a novel kind of sexual conflict, by which Y chromosome-autosome epistasis may result in the spread of male beneficial but female deleterious mutations in a population. We christen this phenomenon Father's Curse. Extending this analytical framework to ZW sex chromosome systems, where males are the heterogametic sex, we also show how W-autosome epistasis can lead to a novel kind of nuclear Mother's Curse. Overall, this study provides a comprehensive framework to understand how genetic transmission asymmetries may both cause and resolve sexual conflicts.
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Affiliation(s)
- J Arvid Ågren
- Department of Molecular Biology and Genetics, Cornell University, Ithaca, NY, 14583, USA
| | - Manisha Munasinghe
- Department of Biological Statistics and Computational Biology, Cornell University, Ithaca, NY, 14853, USA
| | - Andrew G Clark
- Department of Molecular Biology and Genetics, Cornell University, Ithaca, NY, 14583, USA; Department of Biological Statistics and Computational Biology, Cornell University, Ithaca, NY, 14853, USA.
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26
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Genes Relocated Between Drosophila Chromosome Arms Evolve Under Relaxed Selective Constraints Relative to Non-Relocated Genes. J Mol Evol 2018; 86:340-352. [PMID: 29926120 DOI: 10.1007/s00239-018-9849-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2018] [Accepted: 06/11/2018] [Indexed: 10/28/2022]
Abstract
Gene duplication creates a second copy of a gene either in tandem to the ancestral locus or dispersed to another chromosomal location. When the ancestral copy of a dispersed duplicate is lost from the genome, it creates the appearance that the gene was "relocated" from the ancestral locus to the derived location. Gene relocations may be as common as canonical dispersed duplications in which both the ancestral and derived copies are retained. Relocated genes appear to be under more selective constraints than the derived copies of canonical duplications, and they are possibly as conserved as single-copy non-relocated genes. To test this hypothesis, we combined comparative genomics, population genetics, gene expression, and functional analyses to assess the selection pressures acting on relocated, duplicated, and non-relocated single-copy genes in Drosophila genomes. We find that relocated genes evolve faster than single-copy non-relocated genes, and there is no evidence that this faster evolution is driven by positive selection. In addition, relocated genes are less essential for viability and male fertility than single-copy non-relocated genes, suggesting that relocated genes evolve fast because of relaxed selective constraints. However, relocated genes evolve slower than the derived copies of canonical dispersed duplicated genes. We therefore conclude that relocated genes are under more selective constraints than canonical duplicates, but are not as conserved as single-copy non-relocated genes.
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27
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Catalán A, Macias-Muñoz A, Briscoe AD. Evolution of Sex-Biased Gene Expression and Dosage Compensation in the Eye and Brain of Heliconius Butterflies. Mol Biol Evol 2018; 35:2120-2134. [DOI: 10.1093/molbev/msy111] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Affiliation(s)
- Ana Catalán
- Department of Ecology and Evolutionary Biology, University of California, Irvine, CA
- Section of Evolutionary Biology, Department of Biology II, Ludwig Maximilians Universität, Planegg-Martinsried, Germany
| | - Aide Macias-Muñoz
- Department of Ecology and Evolutionary Biology, University of California, Irvine, CA
| | - Adriana D Briscoe
- Department of Ecology and Evolutionary Biology, University of California, Irvine, CA
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28
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Lucchesi JC. Transcriptional modulation of entire chromosomes: dosage compensation. J Genet 2018; 97:357-364. [PMID: 29932054] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
Dosage compensation is a regulatory system designed to equalize the transcription output of the genes of the sex chromosomes that are present in different doses in the sexes (X or Z chromosome, depending on the animal species involved). Different mechanisms of dosage compensation have evolved in different animal groups. In Drosophila males, a complex (male-specific lethal) associates with the X chromosome and enhances the activity of most X-linked genes by increasing the rate of RNAPII elongation. In Caenorhabditis, a complex (dosage compensation complex) that contains a number of proteins involved in condensing chromosomes decreases the level of transcription of both X chromosomes in the XX hermaphrodite. In mammals, dosage compensation is achieved by the inactivation, early during development, of most X-linked genes on one of the two X chromosomes in females. The mechanism involves the synthesis of an RNA (Tsix) that protects one of the two Xs from inactivation, and of another RNA (Xist) that coats the other X chromosome and recruits histone and DNA modifying enzymes. This review will focus on the current progress in understanding the dosage compensation mechanisms in the three taxa where it has been best studied at the molecular level: flies, round worms and mammals.
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Affiliation(s)
- John C Lucchesi
- Department of Biology, Emory University, Atlanta, GA 30322, USA. E-mail:
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29
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Gu L, Walters JR. Evolution of Sex Chromosome Dosage Compensation in Animals: A Beautiful Theory, Undermined by Facts and Bedeviled by Details. Genome Biol Evol 2018; 9:2461-2476. [PMID: 28961969 PMCID: PMC5737844 DOI: 10.1093/gbe/evx154] [Citation(s) in RCA: 70] [Impact Index Per Article: 11.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/22/2017] [Indexed: 12/17/2022] Open
Abstract
Many animals with genetic sex determination harbor heteromorphic sex chromosomes, where the heterogametic sex has half the gene dose of the homogametic sex. This imbalance, if reflected in the abundance of transcripts or proteins, has the potential to deleteriously disrupt interactions between X-linked and autosomal loci in the heterogametic sex. Classical theory predicts that molecular mechanisms will evolve to provide dosage compensation that recovers expression levels comparable to ancestral expression prior to sex chromosome divergence. Such dosage compensating mechanisms may also, secondarily, result in balanced sex-linked gene expression between males and females. However, numerous recent studies addressing sex chromosome dosage compensation (SCDC) in a diversity of animals have yielded a surprising array of patterns concerning dosage compensation in the heterogametic sex, as well as dosage balance between sexes. These results substantially contradict longstanding theory, catalyzing both novel perspectives and new approaches in dosage compensation research. In this review, we summarize the theory, analytical approaches, and recent results concerning evolutionary patterns of SCDC in animals. We also discuss methodological challenges and discrepancies encountered in this research, which often underlie conflicting results. Finally, we discuss what outstanding questions and opportunities exist for future research on SCDC.
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Affiliation(s)
- Liuqi Gu
- Department of Ecology & Evolution, University of Kansas
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30
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31
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Danks GB, Navratilova P, Lenhard B, Thompson EM. Distinct core promoter codes drive transcription initiation at key developmental transitions in a marine chordate. BMC Genomics 2018; 19:164. [PMID: 29482522 PMCID: PMC6389100 DOI: 10.1186/s12864-018-4504-5] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2017] [Accepted: 01/28/2018] [Indexed: 01/28/2023] Open
Abstract
Background Development is largely driven by transitions between transcriptional programs. The initiation of transcription at appropriate sites in the genome is a key component of this and yet few rules governing selection are known. Here, we used cap analysis of gene expression (CAGE) to generate bp-resolution maps of transcription start sites (TSSs) across the genome of Oikopleura dioica, a member of the closest living relatives to vertebrates. Results Our TSS maps revealed promoter features in common with vertebrates, as well as striking differences, and uncovered key roles for core promoter elements in the regulation of development. During spermatogenesis there is a genome-wide shift in mode of transcription initiation characterized by a novel core promoter element. This element was associated with > 70% of male-specific transcription, including the use of cryptic internal promoters within operons. In many cases this led to the exclusion of trans-splice sites, revealing a novel mechanism for regulating which mRNAs receive the spliced leader. Binding of the cell cycle regulator, E2F1, is enriched at the TSS of maternal genes in endocycling nurse nuclei. In addition, maternal promoters lack the TATA-like element found in zebrafish and have broad, rather than sharp, architectures with ordered nucleosomes. Promoters of ribosomal protein genes lack the highly conserved TCT initiator. We also report an association between DNA methylation on transcribed gene bodies and the TATA-box. Conclusions Our results reveal that distinct functional promoter classes and overlapping promoter codes are present in protochordates like in vertebrates, but show extraordinary lineage-specific innovations. Furthermore, we uncover a genome-wide, developmental stage-specific shift in the mode of TSS selection. Our results provide a rich resource for the study of promoter structure and evolution in Metazoa. Electronic supplementary material The online version of this article (10.1186/s12864-018-4504-5) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Gemma B Danks
- Sars International Centre for Marine Molecular Biology, University of Bergen, Bergen, N-5006, Norway.
| | - Pavla Navratilova
- Sars International Centre for Marine Molecular Biology, University of Bergen, Bergen, N-5006, Norway
| | - Boris Lenhard
- Sars International Centre for Marine Molecular Biology, University of Bergen, Bergen, N-5006, Norway.,Computational Regulatory Genomics, MRC London Institute of Medical Sciences, London, W12 0NN, United Kingdom.,Institute of Clinical Sciences, Faculty of Medicine, Imperial College London, London, W12 0NN, United Kingdom
| | - Eric M Thompson
- Sars International Centre for Marine Molecular Biology, University of Bergen, Bergen, N-5006, Norway. .,Department of Biology, University of Bergen, Bergen, N-5006, Norway.
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32
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Campos JL, Johnston KJA, Charlesworth B. The Effects of Sex-Biased Gene Expression and X-Linkage on Rates of Sequence Evolution in Drosophila. Mol Biol Evol 2017; 35:655-665. [DOI: 10.1093/molbev/msx317] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Affiliation(s)
- José Luis Campos
- Institute of Evolutionary Biology, School of Biological Sciences, University of Edinburgh, Edinburgh, United Kingdom
| | - Keira J A Johnston
- Institute of Health and Wellbeing, College of Medical, Veterinary & Life Sciences, University of Glasgow, Glasgow, United Kingdom
| | - Brian Charlesworth
- Institute of Evolutionary Biology, School of Biological Sciences, University of Edinburgh, Edinburgh, United Kingdom
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33
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Beaudry FEG, Barrett SCH, Wright SI. Genomic Loss and Silencing on the Y Chromosomes of Rumex. Genome Biol Evol 2017; 9:3345-3355. [PMID: 29211839 PMCID: PMC5737746 DOI: 10.1093/gbe/evx254] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 11/30/2017] [Indexed: 12/19/2022] Open
Abstract
Across many unrelated lineages of plants and animals, Y chromosomes show a recurrent pattern of gene degeneration and loss, but the relative importance of inefficient selection, adaptive gene silencing, and neutral genetic drift in causing degeneration remain poorly understood. Here, we use next-generation genome and transcriptome sequencing to investigate patterns of ongoing Y chromosome degeneration in two annual plant species of Rumex (Polygonaceae) differing in their degree of degeneration and sex chromosome heteromorphism. We find evidence for both gene loss as well as silencing in these young plant sex chromosomes. Our analyses revealed significantly more gene deletion relative to silencing in R. rothschildianus, which has had a larger nonrecombining region for a longer period than R. hastatulus, consistent with this system being at a more advanced stage of degeneration. Intra- and interspecific comparisons of genomic coverage and heterozygosity indicated that loss of expression precedes gene deletion, implying that the final stages of mutation accumulation and gene loss may often occur neutrally. We found no evidence for adaptive silencing of genes that have lost expression. Our results suggest that the initial spread of deleterious regulatory variants and/or epigenetic silencing may be an important driver of early degeneration of Y chromosomes.
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Affiliation(s)
- Felix E G Beaudry
- Department of Ecology & Evolutionary Biology, University of Toronto, Ontario, Canada
| | - Spencer C H Barrett
- Department of Ecology & Evolutionary Biology, University of Toronto, Ontario, Canada
| | - Stephen I Wright
- Department of Ecology & Evolutionary Biology, University of Toronto, Ontario, Canada
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34
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Levin TC, Malik HS. Rapidly Evolving Toll-3/4 Genes Encode Male-Specific Toll-Like Receptors in Drosophila. Mol Biol Evol 2017; 34:2307-2323. [PMID: 28541576 PMCID: PMC5850136 DOI: 10.1093/molbev/msx168] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
Animal Toll-like receptors (TLRs) have evolved through a pattern of duplication and divergence. Whereas mammalian TLRs directly recognize microbial ligands, Drosophila Tolls bind endogenous ligands downstream of both developmental and immune signaling cascades. Here, we find that most Toll genes in Drosophila evolve slowly with little gene turnover (gains/losses), consistent with their important roles in development and indirect roles in microbial recognition. In contrast, we find that the Toll-3/4 genes have experienced an unusually rapid rate of gene gains and losses, resulting in lineage-specific Toll-3/4s and vastly different gene repertoires among Drosophila species, from zero copies (e.g., D. mojavensis) to nineteen copies (e.g., D. willistoni). In D. willistoni, we find strong evidence for positive selection in Toll-3/4 genes, localized specifically to an extracellular region predicted to overlap with the binding site of Spätzle, the only known ligand of insect Tolls. However, because Spätzle genes are not experiencing similar selective pressures, we hypothesize that Toll-3/4s may be rapidly evolving because they bind to a different ligand, akin to TLRs outside of insects. We further find that most Drosophila Toll-3/4 genes are either weakly expressed or expressed exclusively in males, specifically in the germline. Unlike other Toll genes in D. melanogaster, Toll-3, and Toll-4 have apparently escaped from essential developmental roles, as knockdowns have no substantial effects on viability or male fertility. Based on these findings, we propose that the Toll-3/4 genes represent an exceptionally rapidly evolving lineage of Drosophila Toll genes, which play an unusual, as-yet-undiscovered role in the male germline.
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Affiliation(s)
- Tera C Levin
- Division of Basic Sciences, Fred Hutchinson Cancer Research Center, Seattle, WA
| | - Harmit S Malik
- Division of Basic Sciences, Fred Hutchinson Cancer Research Center, Seattle, WA.,Howard Hughes Medical Institute, Fred Hutchinson Cancer Research Center, Seattle, WA
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35
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Immonen E, Sayadi A, Bayram H, Arnqvist G. Mating Changes Sexually Dimorphic Gene Expression in the Seed Beetle Callosobruchus maculatus. Genome Biol Evol 2017; 9:677-699. [PMID: 28391318 PMCID: PMC5381559 DOI: 10.1093/gbe/evx029] [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: 02/20/2017] [Indexed: 12/11/2022] Open
Abstract
Sexually dimorphic phenotypes arise largely from sex-specific gene expression, which has mainly been characterized in sexually naïve adults. However, we expect sexual dimorphism in transcription to be dynamic and dependent on factors such as reproductive status. Mating induces many behavioral and physiological changes distinct to each sex and is therefore expected to activate regulatory changes in many sex-biased genes. Here, we first characterized sexual dimorphism in gene expression in Callosobruchus maculatus seed beetles. We then examined how females and males respond to mating and how it affects sex-biased expression, both in sex-limited (abdomen) and sex-shared (head and thorax) tissues. Mating responses were largely sex-specific and, as expected, females showed more genes responding compared with males (∼2,000 vs. ∼300 genes in the abdomen, ∼500 vs. ∼400 in the head and thorax, respectively). Of the sex-biased genes present in virgins, 16% (1,041 genes) in the abdomen and 17% (243 genes) in the head and thorax altered their relative expression between the sexes as a result of mating. Sex-bias status changed in 2% of the genes in the abdomen and 4% in the head and thorax following mating. Mating responses involved de-feminization of females and, to a lesser extent, de-masculinization of males relative to their virgin state: mating decreased rather than increased dimorphic expression of sex-biased genes. The fact that regulatory changes of both types of sex-biased genes occurred in both sexes suggests that male- and female-specific selection is not restricted to male- and female-biased genes, respectively, as is sometimes assumed.
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Affiliation(s)
- Elina Immonen
- Department of Ecology and Genetics, Evolutionary Biology Centre (Animal Ecology), Uppsala University, Uppsala
| | - Ahmed Sayadi
- Department of Ecology and Genetics, Evolutionary Biology Centre (Animal Ecology), Uppsala University, Uppsala
| | - Helen Bayram
- Department of Ecology and Genetics, Evolutionary Biology Centre (Animal Ecology), Uppsala University, Uppsala
| | - Göran Arnqvist
- Department of Ecology and Genetics, Evolutionary Biology Centre (Animal Ecology), Uppsala University, Uppsala
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36
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Mongue AJ, Walters JR. The Z chromosome is enriched for sperm proteins in two divergent species of Lepidoptera. Genome 2017; 61:248-253. [PMID: 28961403 DOI: 10.1139/gen-2017-0068] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Genes that promote sexual conflict, such as those with a sex-limited fitness benefit, are expected to accumulate differentially on sex chromosomes relative to autosomes. Few tests of this hypothesis exist for male homogametic (ZZ) taxa, however, and most use RNA expression data to identify such genes. Here, we employ a different identification method by using proteomic analysis of sperm cells to identify genes with a sex-limited benefit. We tested for a bias in genomic location of sperm protein genes in two species of Lepidoptera. An excess of sperm protein genes was identified on the Z chromosomes of both the Carolina sphinx moth (Manduca sexta) and the monarch butterfly (Danaus plexippus). Taking into consideration a Z-autosome fusion in monarchs, we discover that the ancestrally sex-linked portion of the genome is the source of this enrichment, while the newly sex-linked portion still appears similar to autosomes in relative abundance of sperm protein genes. Together, these results point to an enrichment of male-beneficial genes on the Z chromosome and demonstrate the usefulness of proteomic datasets in sexual conflict research.
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Affiliation(s)
- Andrew J Mongue
- Department of Ecology and Evolutionary Biology, University of Kansas, Lawrence, KS, USA.,Department of Ecology and Evolutionary Biology, University of Kansas, Lawrence, KS, USA
| | - James R Walters
- Department of Ecology and Evolutionary Biology, University of Kansas, Lawrence, KS, USA.,Department of Ecology and Evolutionary Biology, University of Kansas, Lawrence, KS, USA
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37
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Meisel RP, Gonzales CA, Luu H. The house fly Y Chromosome is young and minimally differentiated from its ancient X Chromosome partner. Genome Res 2017; 27:1417-1426. [PMID: 28619849 PMCID: PMC5538557 DOI: 10.1101/gr.215509.116] [Citation(s) in RCA: 30] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2016] [Accepted: 06/08/2017] [Indexed: 12/21/2022]
Abstract
Canonical ancient sex chromosome pairs consist of a gene rich X (or Z) Chromosome and a male-limited (or female-limited) Y (or W) Chromosome that is gene poor. In contrast to highly differentiated sex chromosomes, nascent sex chromosome pairs are homomorphic or very similar in sequence content. Nascent sex chromosomes can arise if an existing sex chromosome fuses to an autosome or an autosome acquires a new sex-determining locus/allele. Sex chromosomes often differ between closely related species and can even be polymorphic within species, suggesting that nascent sex chromosomes arise frequently over the course of evolution. Previously documented sex chromosome transitions involve changes to both members of the sex chromosome pair (X and Y, or Z and W). The house fly has sex chromosomes that resemble the ancestral fly karyotype that originated ∼100 million yr ago; therefore, the house fly is expected to have X and Y Chromosomes with different gene content. We tested this hypothesis using whole-genome sequencing and transcriptomic data, and we discovered little evidence for genetic differentiation between the X and Y in house fly. We propose that the house fly has retained the ancient X Chromosome, but the ancestral Y was replaced by an X Chromosome carrying a new male determining gene. Our proposed hypothesis provides a mechanism for how one member of a sex chromosome pair can experience evolutionary turnover while the other member remains unaffected.
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Affiliation(s)
- Richard P Meisel
- Department of Biology and Biochemistry, University of Houston, Houston, Texas 77204, USA
| | - Christopher A Gonzales
- Department of Biology and Biochemistry, University of Houston, Houston, Texas 77204, USA
| | - Hoang Luu
- Department of Biology and Biochemistry, University of Houston, Houston, Texas 77204, USA
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38
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Argyridou E, Huylmans AK, Königer A, Parsch J. X-linkage is not a general inhibitor of tissue-specific gene expression in Drosophila melanogaster. Heredity (Edinb) 2017; 119:27-34. [PMID: 28295031 DOI: 10.1038/hdy.2017.12] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2016] [Revised: 01/05/2017] [Accepted: 02/13/2017] [Indexed: 11/09/2022] Open
Abstract
As a consequence of its difference in copy number between males and females, the X chromosome is subject to unique evolutionary forces and gene regulatory mechanisms. Previous studies of Drosophila melanogaster have shown that the expression of X-linked, testis-specific reporter genes is suppressed in the male germline. However, it is not known whether this phenomenon is restricted to testis-expressed genes or if it is a more general property of genes with tissue-specific expression, which are also underrepresented on the X chromosome. To test this, we compared the expression of three tissue-specific reporter genes (ovary, accessory gland and Malpighian tubule) inserted at various autosomal and X-chromosomal locations. In contrast to testis-specific reporter genes, we found no reduction of X-linked expression in any of the other tissues. In accessory gland and Malpighian tubule, we detected higher expression of the X-linked reporter genes, which suggests that they are at least partially dosage compensated. We found no difference in the tissue-specificity of X-linked and autosomal reporter genes. These findings indicate that, in general, the X chromosome is not a detrimental environment for tissue-specific gene expression and that the suppression of X-linked expression is limited to the male germline.
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Affiliation(s)
- E Argyridou
- Department of Biology II, Faculty of Biology, Ludwig-Maximilians-Universität München (LMU), Planegg-Martinsried, Germany
| | - A K Huylmans
- Department of Biology II, Faculty of Biology, Ludwig-Maximilians-Universität München (LMU), Planegg-Martinsried, Germany
| | - A Königer
- Department of Biology II, Faculty of Biology, Ludwig-Maximilians-Universität München (LMU), Planegg-Martinsried, Germany
| | - J Parsch
- Department of Biology II, Faculty of Biology, Ludwig-Maximilians-Universität München (LMU), Planegg-Martinsried, Germany
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39
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Wright AE, Darolti I, Bloch NI, Oostra V, Sandkam B, Buechel SD, Kolm N, Breden F, Vicoso B, Mank JE. Convergent recombination suppression suggests role of sexual selection in guppy sex chromosome formation. Nat Commun 2017; 8:14251. [PMID: 28139647 PMCID: PMC5290318 DOI: 10.1038/ncomms14251] [Citation(s) in RCA: 88] [Impact Index Per Article: 12.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2016] [Accepted: 12/13/2016] [Indexed: 01/19/2023] Open
Abstract
Sex chromosomes evolve once recombination is halted between a homologous pair of chromosomes. The dominant model of sex chromosome evolution posits that recombination is suppressed between emerging X and Y chromosomes in order to resolve sexual conflict. Here we test this model using whole genome and transcriptome resequencing data in the guppy, a model for sexual selection with many Y-linked colour traits. We show that although the nascent Y chromosome encompasses nearly half of the linkage group, there has been no perceptible degradation of Y chromosome gene content or activity. Using replicate wild populations with differing levels of sexually antagonistic selection for colour, we also show that sexual selection leads to greater expansion of the non-recombining region and increased Y chromosome divergence. These results provide empirical support for longstanding models of sex chromosome catalysis, and suggest an important role for sexual selection and sexual conflict in genome evolution.
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Affiliation(s)
- Alison E. Wright
- Department of Genetics, Evolution and Environment, University College London, Darwin Building, Gower Street, London WC1E 6BT, UK
| | - Iulia Darolti
- Department of Genetics, Evolution and Environment, University College London, Darwin Building, Gower Street, London WC1E 6BT, UK
| | - Natasha I. Bloch
- Department of Genetics, Evolution and Environment, University College London, Darwin Building, Gower Street, London WC1E 6BT, UK
| | - Vicencio Oostra
- Department of Genetics, Evolution and Environment, University College London, Darwin Building, Gower Street, London WC1E 6BT, UK
| | - Ben Sandkam
- Department of Biological Sciences, Simon Fraser University, 8888 University Drive, Burnaby, British Columbia, Canada V5A 1S6
| | - Severine D. Buechel
- Department of Zoology, Stockholm University, Svante Arrheniusväg 18 B, Stockholm 106 91, Sweden
| | - Niclas Kolm
- Department of Zoology, Stockholm University, Svante Arrheniusväg 18 B, Stockholm 106 91, Sweden
| | - Felix Breden
- Department of Biological Sciences, Simon Fraser University, 8888 University Drive, Burnaby, British Columbia, Canada V5A 1S6
| | - Beatriz Vicoso
- Institute of Science and Technology, Am Campus 1A, Klosterneuburg 3400, Austria
| | - Judith E. Mank
- Department of Genetics, Evolution and Environment, University College London, Darwin Building, Gower Street, London WC1E 6BT, UK
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40
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The transcriptional architecture of phenotypic dimorphism. Nat Ecol Evol 2017; 1:6. [PMID: 28812569 DOI: 10.1038/s41559-016-0006] [Citation(s) in RCA: 94] [Impact Index Per Article: 13.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2016] [Accepted: 09/06/2016] [Indexed: 12/11/2022]
Abstract
The profound differences in gene expression between the sexes are increasingly used to study the molecular basis of sexual dimorphism, sexual selection and sexual conflict. Studies of transcriptional architecture, based on comparisons of gene expression, have also been implemented for a wide variety of other intra-specific polymorphisms. These efforts are based on key assumptions regarding the relationship between transcriptional architecture, phenotypic variation and the target of selection. Some of these assumptions are better supported by available evidence than others. In all cases, the evidence is largely circumstantial, leaving considerable gaps in our understanding of the relationship between transcriptional and phenotypic dimorphism.
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41
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Zemp N, Tavares R, Muyle A, Charlesworth D, Marais GAB, Widmer A. Evolution of sex-biased gene expression in a dioecious plant. NATURE PLANTS 2016; 2:16168. [PMID: 27808231 DOI: 10.1038/nplants.2016.168] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/28/2016] [Accepted: 09/29/2016] [Indexed: 05/25/2023]
Abstract
Separate sexes and sex-biased gene expression have repeatedly evolved in animals and plants, but the underlying changes in gene expression remain unknown. Here, we studied a pair of plant species, one in which separate sexes and sex chromosomes evolved recently and one which maintained hermaphrodite flowers resembling the ancestral state, to reconstruct expression changes associated with the evolution of dioecy. We found that sex-biased gene expression has evolved in autosomal and sex-linked genes in the dioecious species. Most expression changes relative to hermaphrodite flowers occurred in females rather than males, with higher and lower expression in females leading to female-biased and male-biased expression, respectively. Expression changes were more common in genes located on the sex chromosomes than the autosomes and led to feminization of the X chromosome and masculinization of the Y chromosome. Our results support a scenario in which sex-biased gene expression evolved during the evolution of dioecy to resolve intralocus sexual conflicts over the allocation of resources.
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Affiliation(s)
- Niklaus Zemp
- ETH Zurich, Institute of Integrative Biology, Universitätstrasse 16, 8092 Zürich, Switzerland
| | - Raquel Tavares
- Université Lyon 1, CNRS, UMR 5558, Laboratoire de Biométrie et Biologie Evolutive, F-69622 Villeurbanne, France
| | - Aline Muyle
- Université Lyon 1, CNRS, UMR 5558, Laboratoire de Biométrie et Biologie Evolutive, F-69622 Villeurbanne, France
| | - Deborah Charlesworth
- University of Edinburgh, Institute of Evolutionary Biology, Edinburgh EH9 3JT, UK
| | - Gabriel A B Marais
- Université Lyon 1, CNRS, UMR 5558, Laboratoire de Biométrie et Biologie Evolutive, F-69622 Villeurbanne, France
| | - Alex Widmer
- ETH Zurich, Institute of Integrative Biology, Universitätstrasse 16, 8092 Zürich, Switzerland
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42
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Huylmans AK, López Ezquerra A, Parsch J, Cordellier M. De Novo Transcriptome Assembly and Sex-Biased Gene Expression in the Cyclical Parthenogenetic Daphnia galeata. Genome Biol Evol 2016; 8:3120-3139. [PMID: 27604882 PMCID: PMC5174735 DOI: 10.1093/gbe/evw221] [Citation(s) in RCA: 35] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/02/2016] [Indexed: 12/20/2022] Open
Abstract
Daphnia species have become models for ecological genomics and exhibit interesting features, such as high phenotypic plasticity and a densely packed genome with many lineage-specific genes. They are also cyclic parthenogenetic, with alternating asexual and sexual cycles and environmental sex determination. Here, we present a de novo transcriptome assembly of over 32,000 D. galeata genes and use it to investigate gene expression in females and spontaneously produced males of two clonal lines derived from lakes in Germany and the Czech Republic. We find that only a low percentage (18%) of genes shows sex-biased expression and that there are many more female-biased gene (FBG) than male-biased gene (MBG). Furthermore, FBGs tend to be more conserved between species than MBGs in both sequence and expression. These patterns may be a consequence of cyclic parthenogenesis leading to a relaxation of purifying selection on MBGs. The two clonal lines show considerable differences in both number and identity of sex-biased genes, suggesting that they may have reproductive strategies differing in their investment in sexual reproduction. Orthologs of key genes in the sex determination and juvenile hormone pathways, which are thought to be important for the transition from asexual to sexual reproduction, are present in D. galeata and highly conserved among Daphnia species.
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Affiliation(s)
- Ann Kathrin Huylmans
- Faculty of Biology, Ludwig-Maximilians-Universität München, Planegg, Germany
- Instititute of Science and Technology Austria, Klosterneuburg, Austria
| | - Alberto López Ezquerra
- Institute for Evolution and Biodiversity, Westfälische-Wilhelms Universität Münster, Münster, Germany
| | - John Parsch
- Faculty of Biology, Ludwig-Maximilians-Universität München, Planegg, Germany
| | - Mathilde Cordellier
- Faculty of Biology, Ludwig-Maximilians-Universität München, Planegg, Germany
- Zoologisches Institut, Universität Hamburg, Hamburg, Germany
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43
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Lewis SH, Webster CL, Salmela H, Obbard DJ. Repeated Duplication of Argonaute2 Is Associated with Strong Selection and Testis Specialization in Drosophila. Genetics 2016; 204:757-769. [PMID: 27535930 PMCID: PMC5068860 DOI: 10.1534/genetics.116.192336] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2016] [Accepted: 08/12/2016] [Indexed: 11/18/2022] Open
Abstract
Argonaute2 (Ago2) is a rapidly evolving nuclease in the Drosophila melanogaster RNA interference (RNAi) pathway that targets viruses and transposable elements in somatic tissues. Here we reconstruct the history of Ago2 duplications across the D. obscura group and use patterns of gene expression to infer new functional specialization. We show that some duplications are old, shared by the entire species group, and that losses may be common, including previously undetected losses in the lineage leading to D. pseudoobscura We find that while the original (syntenic) gene copy has generally retained the ancestral ubiquitous expression pattern, most of the novel Ago2 paralogs have independently specialized to testis-specific expression. Using population genetic analyses, we show that most testis-specific paralogs have significantly lower genetic diversity than the genome-wide average. This suggests recent positive selection in three different species, and model-based analyses provide strong evidence of recent hard selective sweeps in or near four of the six D. pseudoobscura Ago2 paralogs. We speculate that the repeated evolution of testis specificity in obscura group Ago2 genes, combined with their dynamic turnover and strong signatures of adaptive evolution, may be associated with highly derived roles in the suppression of transposable elements or meiotic drive. Our study highlights the lability of RNAi pathways, even within well-studied groups such as Drosophila, and suggests that strong selection may act quickly after duplication in RNAi pathways, potentially giving rise to new and unknown RNAi functions in nonmodel species.
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Affiliation(s)
- Samuel H Lewis
- Institute of Evolutionary Biology, University of Edinburgh, Ashworth Laboratories, EH9 3FL, United Kingdom
| | - Claire L Webster
- Institute of Evolutionary Biology, University of Edinburgh, Ashworth Laboratories, EH9 3FL, United Kingdom
| | - Heli Salmela
- Department of Biosciences, Centre of Excellence in Biological Interactions, University of Helsinki, Finland
| | - Darren J Obbard
- Institute of Evolutionary Biology, University of Edinburgh, Ashworth Laboratories, EH9 3FL, United Kingdom Centre for Immunity, Infection and Evolution, University of Edinburgh, Ashworth Laboratories, EH9 3FL, United Kingdom
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44
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Sex Differences in Drosophila Somatic Gene Expression: Variation and Regulation by doublesex. G3-GENES GENOMES GENETICS 2016; 6:1799-808. [PMID: 27172187 PMCID: PMC4938635 DOI: 10.1534/g3.116.027961] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
Sex differences in gene expression have been widely studied in Drosophila melanogaster. Sex differences vary across strains, but many molecular studies focus on only a single strain, or on genes that show sexually dimorphic expression in many strains. How extensive variability is and whether this variability occurs among genes regulated by sex determination hierarchy terminal transcription factors is unknown. To address these questions, we examine differences in sexually dimorphic gene expression between two strains in Drosophila adult head tissues. We also examine gene expression in doublesex (dsx) mutant strains to determine which sex-differentially expressed genes are regulated by DSX, and the mode by which DSX regulates expression. We find substantial variation in sex-differential expression. The sets of genes with sexually dimorphic expression in each strain show little overlap. The prevalence of different DSX regulatory modes also varies between the two strains. Neither the patterns of DSX DNA occupancy, nor mode of DSX regulation explain why some genes show consistent sex-differential expression across strains. We find that the genes identified as regulated by DSX in this study are enriched with known sites of DSX DNA occupancy. Finally, we find that sex-differentially expressed genes and genes regulated by DSX are highly enriched on the fourth chromosome. These results provide insights into a more complete pool of potential DSX targets, as well as revealing the molecular flexibility of DSX regulation.
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45
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Vizán-Rico HI, Gómez-Zurita J. Testis-specific RNA-Seq of Calligrapha (Chrysomelidae) as a transcriptomic resource for male-biased gene inquiry in Coleoptera. Mol Ecol Resour 2016; 17:533-545. [PMID: 27288908 DOI: 10.1111/1755-0998.12554] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2015] [Revised: 05/23/2016] [Accepted: 05/31/2016] [Indexed: 11/29/2022]
Abstract
We report the architecture of testis transcriptomes of four closely related species of Calligrapha (Chrysomelidae) beetles, which diverged during the last 3 million years. Five cDNA libraries were sequenced using Illumina HiSeq technology, retrieving 102 884-176 514 assembled contigs, of which ~33-45% of these longer than 499 nt were functionally annotated. Annotation and sequence similarity comparisons of these libraries revealed high homogeneity in gene composition and the presence of several functional candidates related to reproduction or reproductive processes (0.72-1.08% of annotated sequences). Stringent sequence similarity analyses of these transcriptomes against empirically demonstrated male-biased genes in Drosophila melanogaster and Tribolium castaneum allowed the identification of 77 homologues in Calligrapha, possible candidates of male-biased expression. Some of these genes - including CG9313, Tektin-A or tomboy40 - were confirmed as orthologs of these male-biased genes using phylogenetic inference and available model insect data, increasing our confidence that they represent functional homologues too. Our transcriptomes are a valuable transcriptomic resource for the analysis of male-biased genes in Calligrapha, which has the added interest of including several female-only species. But it simultaneously represents a landmark for similar studies in Coleoptera, broadening the taxonomic diversity currently represented by the model species T. castaneum, and incipient genomic data in other herbivorous lineages, including weevils, longhorn beetles and leaf beetles.
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Affiliation(s)
- Helena I Vizán-Rico
- Animal Biodiversity and Evolution, Institute of Evolutionary Biology (CSIC-Univ. Pompeu Fabra), Barcelona, 08003, Spain
| | - Jesús Gómez-Zurita
- Animal Biodiversity and Evolution, Institute of Evolutionary Biology (CSIC-Univ. Pompeu Fabra), Barcelona, 08003, Spain
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46
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Nyberg KG, Machado CA. Comparative Expression Dynamics of Intergenic Long Noncoding RNAs in the Genus Drosophila. Genome Biol Evol 2016; 8:1839-58. [PMID: 27189981 PMCID: PMC4943187 DOI: 10.1093/gbe/evw116] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
Thousands of long noncoding RNAs (lncRNAs) have been annotated in eukaryotic genomes, but comparative transcriptomic approaches are necessary to understand their biological impact and evolution. To facilitate such comparative studies in Drosophila, we identified and characterized lncRNAs in a second Drosophilid—the evolutionary model Drosophila pseudoobscura. Using RNA-Seq and computational filtering of protein-coding potential, we identified 1,589 intergenic lncRNA loci in D. pseudoobscura. We surveyed multiple sex-specific developmental stages and found, like in Drosophila melanogaster, increasingly prolific lncRNA expression through male development and an overrepresentation of lncRNAs in the testes. Other trends seen in D. melanogaster, like reduced pupal expression, were not observed. Nonrandom distributions of female-biased and non-testis-specific male-biased lncRNAs between the X chromosome and autosomes are consistent with selection-based models of gene trafficking to optimize genomic location of sex-biased genes. The numerous testis-specific lncRNAs, however, are randomly distributed between the X and autosomes, and we cannot reject the hypothesis that many of these are likely to be spurious transcripts. Finally, using annotated lncRNAs in both species, we identified 134 putative lncRNA homologs between D. pseudoobscura and D. melanogaster and find that many have conserved developmental expression dynamics, making them ideal candidates for future functional analyses.
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Affiliation(s)
- Kevin G Nyberg
- Department of Biology, University of Maryland, College Park
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47
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Contrasting Levels of Molecular Evolution on the Mouse X Chromosome. Genetics 2016; 203:1841-57. [PMID: 27317678 DOI: 10.1534/genetics.116.186825] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2016] [Accepted: 06/08/2016] [Indexed: 11/18/2022] Open
Abstract
The mammalian X chromosome has unusual evolutionary dynamics compared to autosomes. Faster-X evolution of spermatogenic protein-coding genes is known to be most pronounced for genes expressed late in spermatogenesis, but it is unclear if these patterns extend to other forms of molecular divergence. We tested for faster-X evolution in mice spanning three different forms of molecular evolution-divergence in protein sequence, gene expression, and DNA methylation-across different developmental stages of spermatogenesis. We used FACS to isolate individual cell populations and then generated cell-specific transcriptome profiles across different stages of spermatogenesis in two subspecies of house mice (Mus musculus), thereby overcoming a fundamental limitation of previous studies on whole tissues. We found faster-X protein evolution at all stages of spermatogenesis and faster-late protein evolution for both X-linked and autosomal genes. In contrast, there was less expression divergence late in spermatogenesis (slower late) on the X chromosome and for autosomal genes expressed primarily in testis (testis-biased). We argue that slower-late expression divergence reflects strong regulatory constraints imposed during this critical stage of sperm development and that these constraints are particularly acute on the tightly regulated sex chromosomes. We also found slower-X DNA methylation divergence based on genome-wide bisulfite sequencing of sperm from two species of mice (M. musculus and M. spretus), although it is unclear whether slower-X DNA methylation reflects development constraints in sperm or other X-linked phenomena. Our study clarifies key differences in patterns of regulatory and protein evolution across spermatogenesis that are likely to have important consequences for mammalian sex chromosome evolution, male fertility, and speciation.
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48
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Dean R, Zimmer F, Mank JE. The potential role of sexual conflict and sexual selection in shaping the genomic distribution of Mito-nuclear genes. Genome Biol Evol 2016; 6:1096-104. [PMID: 24682150 PMCID: PMC4040984 DOI: 10.1093/gbe/evu063] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Mitochondrial interactions with the nuclear genome represent one of life's most important co-evolved mutualisms. In many organisms, mitochondria are maternally inherited, and in these cases, co-transmission between the mitochondrial and nuclear genes differs across different parts of the nuclear genome, with genes on the X chromosome having two-third probability of co-transmission, compared with one-half for genes on autosomes. These asymmetrical inheritance patterns of mitochondria and different parts of the nuclear genome have the potential to put certain gene combinations in inter-genomic co-adaptation or conflict. Previous work in mammals found strong evidence that the X chromosome has a dearth of genes that interact with the mitochondria (mito-nuclear genes), suggesting that inter-genomic conflict might drive genes off the X onto the autosomes for their male-beneficial effects. Here, we developed this idea to test coadaptation and conflict between mito-nuclear gene combinations across phylogenetically independent sex chromosomes on a far broader scale. We found that, in addition to therian mammals, only Caenorhabditis elegans showed an under-representation of mito-nuclear genes on the sex chromosomes. The remaining species studied showed no overall bias in their distribution of mito-nuclear genes. We discuss possible factors other than inter-genomic conflict that might drive the genomic distribution of mito-nuclear genes.
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Affiliation(s)
- Rebecca Dean
- Department of Genetics, Evolution, and Environment, University College London, London, United Kingdom
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49
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Gallach M, Betrán E. Dosage Compensation and the Distribution of Sex-Biased Gene Expression in Drosophila: Considerations and Genomic Constraints. J Mol Evol 2016; 82:199-206. [PMID: 27059220 PMCID: PMC4866998 DOI: 10.1007/s00239-016-9735-y] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2015] [Accepted: 03/28/2016] [Indexed: 11/02/2022]
Abstract
Several studies in Drosophila have shown a paucity of male-biased genes (i.e., genes that express higher in males than in females) on the X chromosome. Dosage compensation (DC) is a regulatory mechanism of gene expression triggered in males that hypertranscribes the X-linked genes to the level of transcription in females. There are currently two different hypotheses about the effects of DC on the distribution of male-biased genes: (1) it might limit male-expression level, or (2) it might interfere with the male upregulation of gene expression. Here, we used previously published gene expression datasets to reevaluate both hypotheses and introduce a mutually exclusive prediction that helped us to reject the hypothesis that the paucity of male-biased genes in the X chromosome is due to a limit in the male-expression level. Our analysis also uncovers unanticipated details about how DC interferes with the genomic distribution of both, male-biased and female-biased genes. We suggest that DC actually interferes with female downregulation of gene expression and not male upregulation, as previously suggested.
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Affiliation(s)
- Miguel Gallach
- Center for Integrative Bioinformatics Vienna (CIBIV), Max F Perutz Laboratories (MFPL), University of Vienna and Medical University of Vienna, Dr. Bohrgasse 9, 1030, Vienna, Austria.
| | - Esther Betrán
- Department of Biology, University of Texas at Arlington, Arlington, USA
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50
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Baker RH, Narechania A, DeSalle R, Johns PM, Reinhardt JA, Wilkinson GS. Spermatogenesis Drives Rapid Gene Creation and Masculinization of the X Chromosome in Stalk-Eyed Flies (Diopsidae). Genome Biol Evol 2016; 8:896-914. [PMID: 26951781 PMCID: PMC4824122 DOI: 10.1093/gbe/evw043] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
Throughout their evolutionary history, genomes acquire new genetic material that facilitates phenotypic innovation and diversification. Developmental processes associated with reproduction are particularly likely to involve novel genes. Abundant gene creation impacts the evolution of chromosomal gene content and general regulatory mechanisms such as dosage compensation. Numerous studies in model organisms have found complex and, at times contradictory, relationships among these genomic attributes highlighting the need to examine these patterns in other systems characterized by abundant sexual selection. Therefore, we examined the association among novel gene creation, tissue-specific gene expression, and chromosomal gene content within stalk-eyed flies. Flies in this family are characterized by strong sexual selection and the presence of a newly evolved X chromosome. We generated RNA-seq transcriptome data from the testes for three species within the family and from seven additional tissues in the highly dimorphic species, Teleopsis dalmanni. Analysis of dipteran gene orthology reveals dramatic testes-specific gene creation in stalk-eyed flies, involving numerous gene families that are highly conserved in other insect groups. Identification of X-linked genes for the three species indicates that the X chromosome arose prior to the diversification of the family. The most striking feature of this X chromosome is that it is highly masculinized, containing nearly twice as many testes-specific genes as expected based on its size. All the major processes that may drive differential sex chromosome gene content—creation of genes with male-specific expression, development of male-specific expression from pre-existing genes, and movement of genes with male-specific expression—are elevated on the X chromosome of T. dalmanni. This masculinization occurs despite evidence that testes expressed genes do not achieve the same levels of gene expression on the X chromosome as they do on the autosomes.
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Affiliation(s)
- Richard H Baker
- Sackler Institute for Comparative Genomics, American Museum of Natural History, New York, NY
| | - Apurva Narechania
- Sackler Institute for Comparative Genomics, American Museum of Natural History, New York, NY
| | - Rob DeSalle
- Sackler Institute for Comparative Genomics, American Museum of Natural History, New York, NY
| | - Philip M Johns
- Life Sciences Department, Yale-NUS College, Singapore, Singapore
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