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Chen M, Yang C, Zhai X, Wang C, Liu M, Zhang B, Guo X, Wang Y, Li H, Liu Y, Han J, Wang X, Li J, Jia L, Li L. Comprehensive Identification and Characterization of HML-9 Group in Chimpanzee Genome. Viruses 2024; 16:892. [PMID: 38932184 PMCID: PMC11209481 DOI: 10.3390/v16060892] [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: 01/01/2024] [Revised: 05/23/2024] [Accepted: 05/27/2024] [Indexed: 06/28/2024] Open
Abstract
Endogenous retroviruses (ERVs) are related to long terminal repeat (LTR) retrotransposons, comprising gene sequences of exogenous retroviruses integrated into the host genome and inherited according to Mendelian law. They are considered to have contributed greatly to the evolution of host genome structure and function. We previously characterized HERV-K HML-9 in the human genome. However, the biological function of this type of element in the genome of the chimpanzee, which is the closest living relative of humans, largely remains elusive. Therefore, the current study aims to characterize HML-9 in the chimpanzee genome and to compare the results with those in the human genome. Firstly, we report the distribution and genetic structural characterization of the 26 proviral elements and 38 solo LTR elements of HML-9 in the chimpanzee genome. The results showed that the distribution of these elements displayed a non-random integration pattern, and only six elements maintained a relatively complete structure. Then, we analyze their phylogeny and reveal that the identified elements all cluster together with HML-9 references and with those identified in the human genome. The HML-9 integration time was estimated based on the 2-LTR approach, and the results showed that HML-9 elements were integrated into the chimpanzee genome between 14 and 36 million years ago and into the human genome between 18 and 49 mya. In addition, conserved motifs, cis-regulatory regions, and enriched PBS sequence features in the chimpanzee genome were predicted based on bioinformatics. The results show that pathways significantly enriched for ERV LTR-regulated genes found in the chimpanzee genome are closely associated with disease development, including neurological and neurodevelopmental psychiatric disorders. In summary, the identification, characterization, and genomics of HML-9 presented here not only contribute to our understanding of the role of ERVs in primate evolution but also to our understanding of their biofunctional significance.
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Affiliation(s)
- Mingyue Chen
- National 111 Center for Cellular Regulation and Molecular Pharmaceutics, Key Laboratory of Fermentation Engineering, Hubei University of Technology, Wuhan 430068, China;
| | - Caiqin Yang
- State Key Laboratory of Pathogen and Biosecurity, Academy of Military Medical Sciences, Beijing 100071, China; (C.Y.); (X.Z.); (C.W.); (M.L.); (B.Z.); (X.G.); (Y.W.); (H.L.); (Y.L.); (J.H.); (X.W.); (J.L.)
| | - Xiuli Zhai
- State Key Laboratory of Pathogen and Biosecurity, Academy of Military Medical Sciences, Beijing 100071, China; (C.Y.); (X.Z.); (C.W.); (M.L.); (B.Z.); (X.G.); (Y.W.); (H.L.); (Y.L.); (J.H.); (X.W.); (J.L.)
- Department of Microbiology, School of Basic Medicine, Anhui Medical University, Hefei 230032, China
| | - Chunlei Wang
- State Key Laboratory of Pathogen and Biosecurity, Academy of Military Medical Sciences, Beijing 100071, China; (C.Y.); (X.Z.); (C.W.); (M.L.); (B.Z.); (X.G.); (Y.W.); (H.L.); (Y.L.); (J.H.); (X.W.); (J.L.)
- Department of Microbiology, School of Basic Medicine, Anhui Medical University, Hefei 230032, China
| | - Mengying Liu
- State Key Laboratory of Pathogen and Biosecurity, Academy of Military Medical Sciences, Beijing 100071, China; (C.Y.); (X.Z.); (C.W.); (M.L.); (B.Z.); (X.G.); (Y.W.); (H.L.); (Y.L.); (J.H.); (X.W.); (J.L.)
- School of Life Sciences, Tsinghua University, Beijing 100084, China
- College of Life Science and Technology, Beijing University of Chemical Technology, Beijing 100029, China
| | - Bohan Zhang
- State Key Laboratory of Pathogen and Biosecurity, Academy of Military Medical Sciences, Beijing 100071, China; (C.Y.); (X.Z.); (C.W.); (M.L.); (B.Z.); (X.G.); (Y.W.); (H.L.); (Y.L.); (J.H.); (X.W.); (J.L.)
| | - Xing Guo
- State Key Laboratory of Pathogen and Biosecurity, Academy of Military Medical Sciences, Beijing 100071, China; (C.Y.); (X.Z.); (C.W.); (M.L.); (B.Z.); (X.G.); (Y.W.); (H.L.); (Y.L.); (J.H.); (X.W.); (J.L.)
- Department of Microbiology, School of Basic Medicine, Anhui Medical University, Hefei 230032, China
| | - Yanglan Wang
- State Key Laboratory of Pathogen and Biosecurity, Academy of Military Medical Sciences, Beijing 100071, China; (C.Y.); (X.Z.); (C.W.); (M.L.); (B.Z.); (X.G.); (Y.W.); (H.L.); (Y.L.); (J.H.); (X.W.); (J.L.)
- College of Life Science and Technology, Beijing University of Chemical Technology, Beijing 100029, China
| | - Hanping Li
- State Key Laboratory of Pathogen and Biosecurity, Academy of Military Medical Sciences, Beijing 100071, China; (C.Y.); (X.Z.); (C.W.); (M.L.); (B.Z.); (X.G.); (Y.W.); (H.L.); (Y.L.); (J.H.); (X.W.); (J.L.)
| | - Yongjian Liu
- State Key Laboratory of Pathogen and Biosecurity, Academy of Military Medical Sciences, Beijing 100071, China; (C.Y.); (X.Z.); (C.W.); (M.L.); (B.Z.); (X.G.); (Y.W.); (H.L.); (Y.L.); (J.H.); (X.W.); (J.L.)
| | - Jingwan Han
- State Key Laboratory of Pathogen and Biosecurity, Academy of Military Medical Sciences, Beijing 100071, China; (C.Y.); (X.Z.); (C.W.); (M.L.); (B.Z.); (X.G.); (Y.W.); (H.L.); (Y.L.); (J.H.); (X.W.); (J.L.)
| | - Xiaolin Wang
- State Key Laboratory of Pathogen and Biosecurity, Academy of Military Medical Sciences, Beijing 100071, China; (C.Y.); (X.Z.); (C.W.); (M.L.); (B.Z.); (X.G.); (Y.W.); (H.L.); (Y.L.); (J.H.); (X.W.); (J.L.)
| | - Jingyun Li
- State Key Laboratory of Pathogen and Biosecurity, Academy of Military Medical Sciences, Beijing 100071, China; (C.Y.); (X.Z.); (C.W.); (M.L.); (B.Z.); (X.G.); (Y.W.); (H.L.); (Y.L.); (J.H.); (X.W.); (J.L.)
| | - Lei Jia
- State Key Laboratory of Pathogen and Biosecurity, Academy of Military Medical Sciences, Beijing 100071, China; (C.Y.); (X.Z.); (C.W.); (M.L.); (B.Z.); (X.G.); (Y.W.); (H.L.); (Y.L.); (J.H.); (X.W.); (J.L.)
| | - Lin Li
- State Key Laboratory of Pathogen and Biosecurity, Academy of Military Medical Sciences, Beijing 100071, China; (C.Y.); (X.Z.); (C.W.); (M.L.); (B.Z.); (X.G.); (Y.W.); (H.L.); (Y.L.); (J.H.); (X.W.); (J.L.)
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2
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Wei KHC, Chatla K, Bachtrog D. Single-cell RNA-seq of Drosophila miranda testis reveals the evolution and trajectory of germline sex chromosome regulation. PLoS Biol 2024; 22:e3002605. [PMID: 38687805 PMCID: PMC11135767 DOI: 10.1371/journal.pbio.3002605] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2022] [Revised: 05/29/2024] [Accepted: 03/27/2024] [Indexed: 05/02/2024] Open
Abstract
Although sex chromosomes have evolved from autosomes, they often have unusual regulatory regimes that are sex- and cell-type-specific such as dosage compensation (DC) and meiotic sex chromosome inactivation (MSCI). The molecular mechanisms and evolutionary forces driving these unique transcriptional programs are critical for genome evolution but have been, in the case of MSCI in Drosophila, subject to continuous debate. Here, we take advantage of the younger sex chromosomes in D. miranda (XR and the neo-X) to infer how former autosomes acquire sex-chromosome-specific regulatory programs using single-cell and bulk RNA sequencing and ribosome profiling, in a comparative evolutionary context. We show that contrary to mammals and worms, the X down-regulation through germline progression is most consistent with the shutdown of DC instead of MSCI, resulting in half gene dosage at the end of meiosis for all 3 X's. Moreover, lowly expressed germline and meiotic genes on the neo-X are ancestrally lowly expressed, instead of acquired suppression after sex linkage. For the young neo-X, DC is incomplete across all tissue and cell types and this dosage imbalance is rescued by contributions from Y-linked gametologs which produce transcripts that are translated to compensate both gene and protein dosage. We find an excess of previously autosomal testis genes becoming Y-specific, showing that the neo-Y and its masculinization likely resolve sexual antagonism. Multicopy neo-sex genes are predominantly expressed during meiotic stages of spermatogenesis, consistent with their amplification being driven to interfere with mendelian segregation. Altogether, this study reveals germline regulation of evolving sex chromosomes and elucidates the consequences these unique regulatory mechanisms have on the evolution of sex chromosome architecture.
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Affiliation(s)
- Kevin H-C. Wei
- Department of Integrative Biology, University of California Berkeley, Berkeley, California, United States of America
- Department of Zoology, University of British Columbia, Vancouver, British Columbia, Canada
| | - Kamalakar Chatla
- Department of Integrative Biology, University of California Berkeley, Berkeley, California, United States of America
| | - Doris Bachtrog
- Department of Integrative Biology, University of California Berkeley, Berkeley, California, United States of America
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3
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Robben M, Ramesh B, Pau S, Meletis D, Luber J, Demuth J. scRNA-seq Reveals Novel Genetic Pathways and Sex Chromosome Regulation in Tribolium Spermatogenesis. Genome Biol Evol 2024; 16:evae059. [PMID: 38513111 PMCID: PMC10980526 DOI: 10.1093/gbe/evae059] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2023] [Revised: 02/26/2024] [Accepted: 03/14/2024] [Indexed: 03/23/2024] Open
Abstract
Spermatogenesis is critical to sexual reproduction yet evolves rapidly in many organisms. High-throughput single-cell transcriptomics promises unparalleled insight into this important process but understanding can be impeded in nonmodel systems by a lack of known genes that can reliably demarcate biologically meaningful cell populations. Tribolium castaneum, the red flour beetle, lacks known markers for spermatogenesis found in insect species like Drosophila melanogaster. Using single-cell sequencing data collected from adult beetle testes, we implement a strategy for elucidating biologically meaningful cell populations by using transient expression stage identification markers, weighted principal component clustering, and SNP-based haploid/diploid phasing. We identify populations that correspond to observable points in sperm differentiation and find species specific markers for each stage. Our results indicate that molecular pathways underlying spermatogenesis in Coleoptera are substantially diverged from those in Diptera. We also show that most genes on the X chromosome experience meiotic sex chromosome inactivation. Temporal expression of Drosophila MSL complex homologs coupled with spatial analysis of potential chromatin entry sites further suggests that the dosage compensation machinery may mediate escape from meiotic sex chromosome inactivation and postmeiotic reactivation of the X chromosome.
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Affiliation(s)
- Michael Robben
- Department of Computer Science and Engineering, University of Texas at Arlington, Arlington, TX 76019, USA
| | - Balan Ramesh
- Department of Biology, University of Texas at Arlington, Arlington, TX 76019, USA
| | - Shana Pau
- Department of Biology, University of Texas at Arlington, Arlington, TX 76019, USA
| | - Demetra Meletis
- Department of Biology, University of Texas at Arlington, Arlington, TX 76019, USA
| | - Jacob Luber
- Department of Computer Science and Engineering, University of Texas at Arlington, Arlington, TX 76019, USA
| | - Jeffery Demuth
- Department of Biology, University of Texas at Arlington, Arlington, TX 76019, USA
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4
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Hunnicutt KE, Callahan C, Keeble S, Moore EC, Good JM, Larson EL. Different complex regulatory phenotypes underlie hybrid male sterility in divergent rodent crosses. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.10.30.564782. [PMID: 37961317 PMCID: PMC10634954 DOI: 10.1101/2023.10.30.564782] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/15/2023]
Abstract
Hybrid incompatibilities are a critical component of species barriers and may arise due to negative interactions between divergent regulatory elements in parental species. We used a comparative approach to identify common themes in the regulatory phenotypes associated with hybrid male sterility in two divergent rodent crosses, dwarf hamsters and house mice. We investigated three potential characteristic regulatory phenotypes in hybrids including the propensity towards over or underexpression relative to parental species, the influence of developmental stage on the extent of misexpression, and the role of the sex chromosomes on misexpression phenotypes. In contrast to near pervasive overexpression in hybrid house mice, we found that misexpression in hybrid dwarf hamsters was dependent on developmental stage. In both house mouse and dwarf hamster hybrids, however, misexpression increased with the progression of spermatogenesis, although to varying extents and with potentially different consequences. In both systems, we detected sex-chromosome specific overexpression in stages of spermatogenesis where inactivated X chromosome expression was expected, but the hybrid overexpression phenotypes were fundamentally different. Importantly, misexpression phenotypes support the presence of multiple histological blocks to spermatogenesis in dwarf hamster hybrids, including a potential role of meiotic stalling early in spermatogenesis. Collectively, we demonstrate that while there are some similarities in hybrid regulatory phenotypes of house mice and dwarf hamsters, there are also clear differences that point towards unique mechanisms underlying hybrid male sterility in each system. Our results highlight the potential of comparative approaches in helping to understand the importance of disrupted gene regulation in speciation.
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Affiliation(s)
| | - Colin Callahan
- Division of Biological Sciences, University of Montana, Missoula, MT, 59812
| | - Sara Keeble
- Division of Biological Sciences, University of Montana, Missoula, MT, 59812
| | - Emily C. Moore
- University of Denver, Department of Biological Sciences, Denver, CO, 80208
- Division of Biological Sciences, University of Montana, Missoula, MT, 59812
| | - Jeffrey M. Good
- Division of Biological Sciences, University of Montana, Missoula, MT, 59812
| | - Erica L. Larson
- University of Denver, Department of Biological Sciences, Denver, CO, 80208
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5
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Puixeu G, Macon A, Vicoso B. Sex-specific estimation of cis and trans regulation of gene expression in heads and gonads of Drosophila melanogaster. G3 (BETHESDA, MD.) 2023; 13:jkad121. [PMID: 37259621 PMCID: PMC10411594 DOI: 10.1093/g3journal/jkad121] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/05/2023] [Revised: 05/17/2023] [Accepted: 05/17/2023] [Indexed: 06/02/2023]
Abstract
The regulatory architecture of gene expression is known to differ substantially between sexes in Drosophila, but most studies performed so far used whole-body data and only single crosses, which may have limited their scope to detect patterns that are robust across tissues and biological replicates. Here, we use allele-specific gene expression of parental and reciprocal hybrid crosses between 6 Drosophila melanogaster inbred lines to quantify cis- and trans-regulatory variation in heads and gonads of both sexes separately across 3 replicate crosses. Our results suggest that female and male heads, as well as ovaries, have a similar regulatory architecture. On the other hand, testes display more and substantially different cis-regulatory effects, suggesting that sex differences in the regulatory architecture that have been previously observed may largely derive from testis-specific effects. We also examine the difference in cis-regulatory variation of genes across different levels of sex bias in gonads and heads. Consistent with the idea that intersex correlations constrain expression and can lead to sexual antagonism, we find more cis variation in unbiased and moderately biased genes in heads. In ovaries, reduced cis variation is observed for male-biased genes, suggesting that cis variants acting on these genes in males do not lead to changes in ovary expression. Finally, we examine the dominance patterns of gene expression and find that sex- and tissue-specific patterns of inheritance as well as trans-regulatory variation are highly variable across biological crosses, although these were performed in highly controlled experimental conditions. This highlights the importance of using various genetic backgrounds to infer generalizable patterns.
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Affiliation(s)
- Gemma Puixeu
- Institute of Science and Technology Austria, Am Campus 1, Klosterneuburg 3400, Austria
| | - Ariana Macon
- Institute of Science and Technology Austria, Am Campus 1, Klosterneuburg 3400, Austria
| | - Beatriz Vicoso
- Institute of Science and Technology Austria, Am Campus 1, Klosterneuburg 3400, Austria
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6
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Hunnicutt KE, Good JM, Larson EL. Unraveling patterns of disrupted gene expression across a complex tissue. Evolution 2022; 76:275-291. [PMID: 34882778 PMCID: PMC9355168 DOI: 10.1111/evo.14420] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2021] [Revised: 11/11/2021] [Accepted: 11/26/2021] [Indexed: 02/03/2023]
Abstract
Whole tissue RNASeq is the standard approach for studying gene expression divergence in evolutionary biology and provides a snapshot of the comprehensive transcriptome for a given tissue. However, whole tissues consist of diverse cell types differing in expression profiles, and the cellular composition of these tissues can evolve across species. Here, we investigate the effects of different cellular composition on whole tissue expression profiles. We compared gene expression from whole testes and enriched spermatogenesis populations in two species of house mice, Mus musculus musculus and M. m. domesticus, and their sterile and fertile F1 hybrids, which differ in both cellular composition and regulatory dynamics. We found that cellular composition differences skewed expression profiles and differential gene expression in whole testes samples. Importantly, both approaches were able to detect large-scale patterns such as disrupted X chromosome expression, although whole testes sampling resulted in decreased power to detect differentially expressed genes. We encourage researchers to account for histology in RNASeq and consider methods that reduce sample complexity whenever feasible. Ultimately, we show that differences in cellular composition between tissues can modify expression profiles, potentially altering inferred gene ontological processes, insights into gene network evolution, and processes governing gene expression evolution.
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Affiliation(s)
| | - Jeffrey M. Good
- University of Montana, Division of Biological Sciences, Missoula, MO, 59812
| | - Erica L. Larson
- University of Denver, Department of Biological Sciences, Denver, CO, 80208
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7
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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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8
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Rivard EL, Ludwig AG, Patel PH, Grandchamp A, Arnold SE, Berger A, Scott EM, Kelly BJ, Mascha GC, Bornberg-Bauer E, Findlay GD. A putative de novo evolved gene required for spermatid chromatin condensation in Drosophila melanogaster. PLoS Genet 2021; 17:e1009787. [PMID: 34478447 PMCID: PMC8445463 DOI: 10.1371/journal.pgen.1009787] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2021] [Revised: 09/16/2021] [Accepted: 08/19/2021] [Indexed: 02/07/2023] Open
Abstract
Comparative genomics has enabled the identification of genes that potentially evolved de novo from non-coding sequences. Many such genes are expressed in male reproductive tissues, but their functions remain poorly understood. To address this, we conducted a functional genetic screen of over 40 putative de novo genes with testis-enriched expression in Drosophila melanogaster and identified one gene, atlas, required for male fertility. Detailed genetic and cytological analyses showed that atlas is required for proper chromatin condensation during the final stages of spermatogenesis. Atlas protein is expressed in spermatid nuclei and facilitates the transition from histone- to protamine-based chromatin packaging. Complementary evolutionary analyses revealed the complex evolutionary history of atlas. The protein-coding portion of the gene likely arose at the base of the Drosophila genus on the X chromosome but was unlikely to be essential, as it was then lost in several independent lineages. Within the last ~15 million years, however, the gene moved to an autosome, where it fused with a conserved non-coding RNA and evolved a non-redundant role in male fertility. Altogether, this study provides insight into the integration of novel genes into biological processes, the links between genomic innovation and functional evolution, and the genetic control of a fundamental developmental process, gametogenesis.
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Affiliation(s)
- Emily L. Rivard
- College of the Holy Cross, Worcester, Massachusetts, United States of America
| | - Andrew G. Ludwig
- College of the Holy Cross, Worcester, Massachusetts, United States of America
| | - Prajal H. Patel
- College of the Holy Cross, Worcester, Massachusetts, United States of America
| | | | - Sarah E. Arnold
- College of the Holy Cross, Worcester, Massachusetts, United States of America
| | | | - Emilie M. Scott
- College of the Holy Cross, Worcester, Massachusetts, United States of America
| | - Brendan J. Kelly
- College of the Holy Cross, Worcester, Massachusetts, United States of America
| | - Grace C. Mascha
- College of the Holy Cross, Worcester, Massachusetts, United States of America
| | - Erich Bornberg-Bauer
- University of Münster, Münster, Germany
- Max Planck Institute for Developmental Biology, Tübingen, Germany
| | - Geoffrey D. Findlay
- College of the Holy Cross, Worcester, Massachusetts, United States of America
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Molla Herman A, Brasset E. Rhino breaks the deadlock in Drosophila testis. PLoS Genet 2021; 17:e1009702. [PMID: 34473721 PMCID: PMC8412255 DOI: 10.1371/journal.pgen.1009702] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Affiliation(s)
- Anahi Molla Herman
- Collège de France, CIRB, CNRS INSERM UMR 7241, PSL Research University, Paris, France
| | - Emilie Brasset
- iGReD, Université Clermont Auvergne, CNRS, INSERM, Faculté de Médecine, Clermont-Ferrand, France
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10
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Witt E, Shao Z, Hu C, Krause HM, Zhao L. Single-cell RNA-sequencing reveals pre-meiotic X-chromosome dosage compensation in Drosophila testis. PLoS Genet 2021; 17:e1009728. [PMID: 34403408 PMCID: PMC8396764 DOI: 10.1371/journal.pgen.1009728] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2021] [Revised: 08/27/2021] [Accepted: 07/20/2021] [Indexed: 11/18/2022] Open
Abstract
Dosage compensation equalizes X-linked expression between XY males and XX females. In male fruit flies, expression levels of the X-chromosome are increased approximately two-fold to compensate for their single X chromosome. In testis, dosage compensation is thought to cease during meiosis; however, the timing and degree of the resulting transcriptional suppression is difficult to separate from global meiotic downregulation of each chromosome. To address this, we analyzed testis single-cell RNA-sequencing (scRNA-seq) data from two Drosophila melanogaster strains. We found evidence that the X chromosome is equally transcriptionally active as autosomes in somatic and pre-meiotic cells, and less transcriptionally active than autosomes in meiotic and post-meiotic cells. In cells experiencing dosage compensation, close proximity to MSL (male-specific lethal) chromatin entry sites (CES) correlates with increased X chromosome transcription. We found low or undetectable levels of germline expression of most msl genes, mle, roX1 and roX2 via scRNA-seq and RNA-FISH, and no evidence of germline nuclear roX1/2 localization. Our results suggest that, although dosage compensation occurs in somatic and pre-meiotic germ cells in Drosophila testis, there might be non-canonical factors involved in the dosage compensation mechanism. The single-cell expression patterns and enrichment statistics of detected genes can be explored interactively in our database: https://zhao.labapps.rockefeller.edu/gene-expr/.
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Affiliation(s)
- Evan Witt
- Laboratory of Evolutionary Genetics and Genomics, The Rockefeller University, New York, New York, United States of America
| | - Zhantao Shao
- Department of Molecular Genetics and The Donnelly Centre for Cellular and Biomolecular Research, University of Toronto, Toronto, Ontario, Canada
| | - Chun Hu
- Department of Molecular Genetics and The Donnelly Centre for Cellular and Biomolecular Research, University of Toronto, Toronto, Ontario, Canada
| | - Henry M. Krause
- Department of Molecular Genetics and The Donnelly Centre for Cellular and Biomolecular Research, University of Toronto, Toronto, Ontario, Canada
| | - Li Zhao
- Laboratory of Evolutionary Genetics and Genomics, The Rockefeller University, New York, New York, United States of America
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11
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Presgraves DC, Meiklejohn CD. Hybrid Sterility, Genetic Conflict and Complex Speciation: Lessons From the Drosophila simulans Clade Species. Front Genet 2021; 12:669045. [PMID: 34249091 PMCID: PMC8261240 DOI: 10.3389/fgene.2021.669045] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2021] [Accepted: 05/20/2021] [Indexed: 12/31/2022] Open
Abstract
The three fruitfly species of the Drosophila simulans clade- D. simulans, D. mauritiana, and D. sechellia- have served as important models in speciation genetics for over 40 years. These species are reproductively isolated by geography, ecology, sexual signals, postmating-prezygotic interactions, and postzygotic genetic incompatibilities. All pairwise crosses between these species conform to Haldane's rule, producing fertile F1 hybrid females and sterile F1 hybrid males. The close phylogenetic proximity of the D. simulans clade species to the model organism, D. melanogaster, has empowered genetic analyses of their species differences, including reproductive incompatibilities. But perhaps no phenotype has been subject to more continuous and intensive genetic scrutiny than hybrid male sterility. Here we review the history, progress, and current state of our understanding of hybrid male sterility among the D. simulans clade species. Our aim is to integrate the available information from experimental and population genetics analyses bearing on the causes and consequences of hybrid male sterility. We highlight numerous conclusions that have emerged as well as issues that remain unresolved. We focus on the special role of sex chromosomes, the fine-scale genetic architecture of hybrid male sterility, and the history of gene flow between species. The biggest surprises to emerge from this work are that (i) genetic conflicts may be an important general force in the evolution of hybrid incompatibility, (ii) hybrid male sterility is polygenic with contributions of complex epistasis, and (iii) speciation, even among these geographically allopatric taxa, has involved the interplay of gene flow, negative selection, and positive selection. These three conclusions are marked departures from the classical views of speciation that emerged from the modern evolutionary synthesis.
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Affiliation(s)
- Daven C. Presgraves
- Department of Biology, University of Rochester, Rochester, NY, United States
| | - Colin D. Meiklejohn
- School of Biological Sciences, University of Nebraska, Lincoln, NE, United States
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12
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Kulikov AM, Sorokina SY, Melnikov AI, Gornostaev NG, Seleznev DG, Lazebny OE. The effects of the sex chromosomes on the inheritance of species-specific traits of the copulatory organ shape in Drosophila virilis and Drosophila lummei. PLoS One 2020; 15:e0244339. [PMID: 33373382 PMCID: PMC7771703 DOI: 10.1371/journal.pone.0244339] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2020] [Accepted: 12/07/2020] [Indexed: 11/30/2022] Open
Abstract
The shape of the male genitalia in many taxa is the most rapidly evolving morphological structure, often driving reproductive isolation, and is therefore widely used in systematics as a key character to distinguish between sibling species. However, only a few studies have used the genital arch of the male copulatory organ as a model to study the genetic basis of species-specific differences in the Drosophila copulatory system. Moreover, almost nothing is known about the effects of the sex chromosomes on the shape of the male mating organ. In our study, we used a set of crosses between D. virilis and D. lummei and applied the methods of quantitative genetics to assess the variability of the shape of the male copulatory organ and the effects of the sex chromosomes and autosomes on its variance. Our results showed that the male genital shape depends on the species composition of the sex chromosomes and autosomes. Epistatic interactions of the sex chromosomes with autosomes and the species origin of the Y-chromosome in a male in interspecific crosses also influenced the expression of species-specific traits in the shape of the male copulatory system. Overall, the effects of sex chromosomes were comparable to the effects of autosomes despite the great differences in gene numbers between them. It may be reasonably considered that sexual selection for specific genes associated with the shape of the male mating organ prevents the demasculinization of the X chromosome.
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Affiliation(s)
- Alex M. Kulikov
- Department of Evolutionary Genetics of Development, Koltzov Institute of Developmental Biology of the Russian Academy of Sciences, Moscow, Russia
| | - Svetlana Yu. Sorokina
- Department of Evolutionary Genetics of Development, Koltzov Institute of Developmental Biology of the Russian Academy of Sciences, Moscow, Russia
| | - Anton I. Melnikov
- Department of Evolutionary Genetics of Development, Koltzov Institute of Developmental Biology of the Russian Academy of Sciences, Moscow, Russia
| | - Nick G. Gornostaev
- Department of Evolutionary Genetics of Development, Koltzov Institute of Developmental Biology of the Russian Academy of Sciences, Moscow, Russia
| | - Dmitriy G. Seleznev
- Department of Ecology of Aquatic Invertebrates, Papanin Institute for Biology of Inland Waters of the Russian Academy of Sciences, Borok village, Yaroslavl Region, Russia
| | - Oleg E. Lazebny
- Department of Evolutionary Genetics of Development, Koltzov Institute of Developmental Biology of the Russian Academy of Sciences, Moscow, Russia
- * E-mail:
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13
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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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14
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Bachtrog D. The Y Chromosome as a Battleground for Intragenomic Conflict. Trends Genet 2020; 36:510-522. [PMID: 32448494 DOI: 10.1016/j.tig.2020.04.008] [Citation(s) in RCA: 24] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2020] [Revised: 04/17/2020] [Accepted: 04/21/2020] [Indexed: 12/12/2022]
Abstract
Y chromosomes are typically viewed as genetic wastelands with few intact genes. Recent genomic analyses in Drosophila, however, show that gene gain is prominent on young Y chromosomes. Meiosis- and RNAi-related genes often coamplify on recently formed X and Y chromosomes, are testis-expressed, and produce antisense transcripts and short RNAs. RNAi pathways are also involved in suppressing sex ratio drive in Drosophila. These observations paint a dynamic picture of sex chromosome differentiation, suggesting that rapidly evolving genomic battles over segregation are rampant on young sex chromosomes and utilize RNAi to defend the genome against selfish elements that manipulate fair meiosis. Recurrent sex chromosome drive can have profound ecological, evolutionary, and cellular impacts and account for unique features of sex chromosomes.
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Affiliation(s)
- Doris Bachtrog
- Department of Integrative Biology, University of California Berkeley, Berkeley, CA 94720, USA.
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15
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Taxiarchi C, Kranjc N, Kriezis A, Kyrou K, Bernardini F, Russell S, Nolan T, Crisanti A, Galizi R. High-resolution transcriptional profiling of Anopheles gambiae spermatogenesis reveals mechanisms of sex chromosome regulation. Sci Rep 2019; 9:14841. [PMID: 31619757 PMCID: PMC6795909 DOI: 10.1038/s41598-019-51181-1] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2019] [Accepted: 09/25/2019] [Indexed: 12/20/2022] Open
Abstract
Although of high priority for the development of genetic tools to control malaria-transmitting mosquitoes, only a few germline-specific regulatory regions have been characterised to date and the presence of global regulatory mechanisms, such as dosage compensation and meiotic sex chromosome inactivation (MSCI), are mostly assumed from transcriptomic analyses of reproductive tissues or whole gonads. In such studies, samples include a significant portion of somatic tissues inevitably complicating the reconstruction of a defined transcriptional map of gametogenesis. By exploiting recent advances in transgenic technologies and gene editing tools, combined with fluorescence-activated cell sorting and RNA sequencing, we have separated four distinct cell lineages from the Anopheles gambiae male gonads: premeiotic, meiotic (primary and secondary spermatocytes) and postmeiotic. By comparing the overall expression levels of X-linked and autosomal genes across the four populations, we revealed a striking transcriptional repression of the X chromosome coincident with the meiotic phase, classifiable as MSCI, and highlighted genes that may evade silencing. In addition, chromosome-wide median expression ratios of the premeiotic population confirmed the absence of dosage compensation in the male germline. Applying differential expression analysis, we highlighted genes and transcript isoforms enriched at specific timepoints and reconstructed the expression dynamics of the main biological processes regulating the key stages of sperm development and maturation. We generated the first transcriptomic atlas of A. gambiae spermatogenesis that will expand the available toolbox for the genetic engineering of vector control technologies. We also describe an innovative and multidimensional approach to isolate specific cell lineages that can be used for the targeted analysis of other A. gambiae organs or transferred to other medically relevant species and model organisms.
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Affiliation(s)
- Chrysanthi Taxiarchi
- Department of Life Sciences, Imperial College London, London, UK
- Department of Experimental Medicine, University of Perugia, Perugia, Italy
| | - Nace Kranjc
- Department of Life Sciences, Imperial College London, London, UK
| | - Antonios Kriezis
- Department of Life Sciences, Imperial College London, London, UK
| | - Kyros Kyrou
- Department of Life Sciences, Imperial College London, London, UK
| | | | - Steven Russell
- Department of Genetics, University of Cambridge, Cambridge, UK
| | - Tony Nolan
- Department of Life Sciences, Imperial College London, London, UK
- Department of Vector Biology, Liverpool School of Tropical Medicine, Liverpool, UK
| | - Andrea Crisanti
- Department of Life Sciences, Imperial College London, London, UK
| | - Roberto Galizi
- Department of Life Sciences, Imperial College London, London, UK.
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16
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Ellison C, Bachtrog D. Recurrent gene co-amplification on Drosophila X and Y chromosomes. PLoS Genet 2019; 15:e1008251. [PMID: 31329593 PMCID: PMC6690552 DOI: 10.1371/journal.pgen.1008251] [Citation(s) in RCA: 30] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2018] [Revised: 08/12/2019] [Accepted: 06/18/2019] [Indexed: 12/19/2022] Open
Abstract
Y chromosomes often contain amplified genes which can increase dosage of male fertility genes and counteract degeneration via gene conversion. Here we identify genes with increased copy number on both X and Y chromosomes in various species of Drosophila, a pattern that has previously been associated with sex chromosome drive involving the Slx and Sly gene families in mice. We show that recurrent X/Y co-amplification appears to be an important evolutionary force that has shaped gene content evolution of sex chromosomes in Drosophila. We demonstrate that convergent acquisition and amplification of testis expressed gene families are common on Drosophila sex chromosomes, and especially on recently formed ones, and we carefully characterize one putative novel X/Y co-amplification system. We find that co-amplification of the S-Lap1/GAPsec gene pair on both the X and the Y chromosome occurred independently several times in members of the D. obscura group, where this normally autosomal gene pair is sex-linked due to a sex chromosome-autosome fusion. We explore several evolutionary scenarios that would explain this pattern of co-amplification. Investigation of gene expression and short RNA profiles at the S-Lap1/GAPsec system suggest that, like Slx/Sly in mice, these genes may be remnants of a cryptic sex chromosome drive system, however additional transgenic experiments will be necessary to validate this model. Regardless of whether sex chromosome drive is responsible for this co-amplification, our findings suggest that recurrent gene duplications between X and Y sex chromosomes could have a widespread effect on genomic and evolutionary patterns, including the epigenetic regulation of sex chromosomes, the distribution of sex-biased genes, and the evolution of hybrid sterility.
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Affiliation(s)
- Christopher Ellison
- Department of Integrative Biology, University of California Berkeley, Berkeley, California, United States of America
| | - Doris Bachtrog
- Department of Integrative Biology, University of California Berkeley, Berkeley, California, United States of America
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17
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Abstract
The evolution of heteromorphic sex chromosomes has occurred independently many times in different lineages. The differentiation of sex chromosomes leads to dramatic changes in sequence composition and function and guides the evolutionary trajectory and utilization of genes in pivotal sex determination and reproduction roles. In addition, meiotic recombination and pairing mechanisms are key in orchestrating the resultant impact, retention and maintenance of heteromorphic sex chromosomes, as the resulting exposure of unpaired DNA at meiosis triggers ancient repair and checkpoint pathways. In this review, we summarize the different ways in which sex chromosome systems are organized at meiosis, how pairing is affected, and differences in unpaired DNA responses. We hypothesize that lineage specific differences in meiotic organization is not only a consequence of sex chromosome evolution, but that the establishment of epigenetic changes on sex chromosomes contributes toward their evolutionary conservation.
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Affiliation(s)
- Tasman Daish
- Comparative Genome Biology Laboratory, Department of Molecular and Biomedical Science, School of Biological Sciences, The University of Adelaide, Adelaide, SA, Australia
| | - Frank Grützner
- Comparative Genome Biology Laboratory, Department of Molecular and Biomedical Science, School of Biological Sciences, The University of Adelaide, Adelaide, SA, Australia.
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18
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Nozawa M, Ikeo K, Gojobori T. Gene-by-Gene or Localized Dosage Compensation on the Neo-X Chromosome in Drosophila miranda. Genome Biol Evol 2018; 10:1875-1881. [PMID: 29986000 PMCID: PMC6071650 DOI: 10.1093/gbe/evy148] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/06/2018] [Indexed: 12/31/2022] Open
Abstract
Many organisms have a global mechanism for dosage compensation (DC) operating along the entire male X chromosome, which equalizes gene expression on the male X with that on the two Xs in females and/or on autosomes. At the initial stage of sex chromosome evolution, however, gene-by-gene (or localized) DC may also be necessary because the degeneration of Y-linked genes occurs independently at different times. We therefore tested whether the up-regulation of X-linked genes depends on the status of their Y-linked homologs, using the young sex chromosomes, neo-X and neo-Y, in Drosophila miranda. In support of the presence of gene-by-gene DC, the extent of up-regulation in males was indeed higher for neo-X-linked genes with pseudogenized neo-Y-linked homologs than for neo-X-linked genes with functional neo-Y-linked homologs. Further molecular evolutionary analysis also supports the idea that many individual neo-X-linked genes first acquired the potential for up-regulation, which then enabled the pseudogenization of neo-Y-linked homologs, without serious deleterious effects on male fitness.
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Affiliation(s)
- Masafumi Nozawa
- Department of Biological Sciences, Tokyo Metropolitan University, Hachioji, Japan
- Research Center for Genomics and Bioinformatics, Tokyo Metropolitan University, Hachioji, Japan
| | - Kazuho Ikeo
- Center for Information Biology, National Institute of Genetics, Mishima, Japan
- Department of Genetics, SOKENDAI, Mishima, Japan
| | - Takashi Gojobori
- King Abdullah University of Science and Technology (KAUST), Biological and Environmental Science and Engineering, Computational Bioscience Research Center, Thuwal, Kingdom of Saudi Arabia
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19
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Llopart A. Faster‐X evolution of gene expression is driven by recessive adaptive
cis
‐regulatory variation in
Drosophila. Mol Ecol 2018; 27:3811-3821. [DOI: 10.1111/mec.14708] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2017] [Revised: 03/28/2018] [Accepted: 04/05/2018] [Indexed: 12/30/2022]
Affiliation(s)
- Ana Llopart
- Department of Biology The University of Iowa Iowa City Iowa
- Interdisciplinary Graduate Program in Genetics The University of Iowa Iowa City Iowa
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20
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Argyridou E, Parsch J. Regulation of the X Chromosome in the Germline and Soma of Drosophila melanogaster Males. Genes (Basel) 2018; 9:genes9050242. [PMID: 29734690 PMCID: PMC5977182 DOI: 10.3390/genes9050242] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2018] [Revised: 04/27/2018] [Accepted: 04/27/2018] [Indexed: 12/22/2022] Open
Abstract
During the evolution of heteromorphic sex chromosomes, the sex-specific Y chromosome degenerates, while the X chromosome evolves new mechanisms of regulation. Using bioinformatic and experimental approaches, we investigate the expression of the X chromosome in Drosophila melanogaster. We observe nearly complete X chromosome dosage compensation in male somatic tissues, but not in testis. The X chromosome contains disproportionately fewer genes with high expression in testis than the autosomes, even after accounting for the lack of dosage compensation, which suggests that another mechanism suppresses their expression in the male germline. This is consistent with studies of reporter genes and transposed genes, which find that the same gene has higher expression when autosomal than when X-linked. Using a new reporter gene that is expressed in both testis and somatic tissues, we find that the suppression of X-linked gene expression is limited to genes with high expression in testis and that the extent of the suppression is positively correlated with expression level.
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Affiliation(s)
- Eliza Argyridou
- Division of Evolutionary Biology, Faculty of Biology, LMU Munich, Grosshaderner Str. 2, 82152 Planegg-Martinsried, Germany.
| | - John Parsch
- Division of Evolutionary Biology, Faculty of Biology, LMU Munich, Grosshaderner Str. 2, 82152 Planegg-Martinsried, Germany.
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21
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Samata M, Akhtar A. Dosage Compensation of the X Chromosome: A Complex Epigenetic Assignment Involving Chromatin Regulators and Long Noncoding RNAs. Annu Rev Biochem 2018; 87:323-350. [PMID: 29668306 DOI: 10.1146/annurev-biochem-062917-011816] [Citation(s) in RCA: 73] [Impact Index Per Article: 12.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
X chromosome regulation represents a prime example of an epigenetic phenomenon where coordinated regulation of a whole chromosome is required. In flies, this is achieved by transcriptional upregulation of X chromosomal genes in males to equalize the gene dosage differences in females. Chromatin-bound proteins and long noncoding RNAs (lncRNAs) constituting a ribonucleoprotein complex known as the male-specific lethal (MSL) complex or the dosage compensation complex mediate this process. MSL complex members decorate the male X chromosome, and their absence leads to male lethality. The male X chromosome is also enriched with histone H4 lysine 16 acetylation (H4K16ac), indicating that the chromatin compaction status of the X chromosome also plays an important role in transcriptional activation. How the X chromosome is specifically targeted and how dosage compensation is mechanistically achieved are central questions for the field. Here, we review recent advances, which reveal a complex interplay among lncRNAs, the chromatin landscape, transcription, and chromosome conformation that fine-tune X chromosome gene expression.
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Affiliation(s)
- Maria Samata
- Department of Chromatin Regulation, Max Planck Institute of Immunobiology and Epigenetics, 79108 Freiburg im Breisgau, Germany; .,Faculty of Biology, University of Freiburg, 79104 Freiburg im Breisgau, Germany
| | - Asifa Akhtar
- Department of Chromatin Regulation, Max Planck Institute of Immunobiology and Epigenetics, 79108 Freiburg im Breisgau, Germany;
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22
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Mahajan S, Bachtrog D. Convergent evolution of Y chromosome gene content in flies. Nat Commun 2017; 8:785. [PMID: 28978907 PMCID: PMC5627270 DOI: 10.1038/s41467-017-00653-x] [Citation(s) in RCA: 37] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2016] [Accepted: 07/18/2017] [Indexed: 11/25/2022] Open
Abstract
Sex-chromosomes have formed repeatedly across Diptera from ordinary autosomes, and X-chromosomes mostly conserve their ancestral genes. Y-chromosomes are characterized by abundant gene-loss and an accumulation of repetitive DNA, yet the nature of the gene repertoire of fly Y-chromosomes is largely unknown. Here we trace gene-content evolution of Y-chromosomes across 22 Diptera species, using a subtraction pipeline that infers Y genes from male and female genome, and transcriptome data. Few genes remain on old Y-chromosomes, but the number of inferred Y-genes varies substantially between species. Young Y-chromosomes still show clear evidence of their autosomal origins, but most genes on old Y-chromosomes are not simply remnants of genes originally present on the proto-sex-chromosome that escaped degeneration, but instead were recruited secondarily from autosomes. Despite almost no overlap in Y-linked gene content in different species with independently formed sex-chromosomes, we find that Y-linked genes have evolved convergent gene functions associated with testis expression. Thus, male-specific selection appears as a dominant force shaping gene-content evolution of Y-chromosomes across fly species. While X-chromosome gene content tends to be conserved, Y-chromosome evolution is dynamic and difficult to reconstruct. Here, Mahajan and Bachtrog use a subtraction pipeline to identify Y-linked genes in 22 Diptera species, revealing patterns of Y-chromosome gene-content evolution.
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Affiliation(s)
- Shivani Mahajan
- Department of Integrative Biology, University of California Berkeley, Berkeley, California, 94720, USA
| | - Doris Bachtrog
- Department of Integrative Biology, University of California Berkeley, Berkeley, California, 94720, USA.
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23
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Huylmans AK, Macon A, Vicoso B. Global Dosage Compensation Is Ubiquitous in Lepidoptera, but Counteracted by the Masculinization of the Z Chromosome. Mol Biol Evol 2017; 34:2637-2649. [PMID: 28957502 PMCID: PMC5850747 DOI: 10.1093/molbev/msx190] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
While chromosome-wide dosage compensation of the X chromosome has been found in many species, studies in ZW clades have indicated that compensation of the Z is more localized and/or incomplete. In the ZW Lepidoptera, some species show complete compensation of the Z chromosome, while others lack full equalization, but what drives these inconsistencies is unclear. Here, we compare patterns of male and female gene expression on the Z chromosome of two closely related butterfly species, Papilio xuthus and Papilio machaon, and in multiple tissues of two moths species, Plodia interpunctella and Bombyx mori, which were previously found to differ in the extent to which they equalize Z-linked gene expression between the sexes. We find that, while some species and tissues seem to have incomplete dosage compensation, this is in fact due to the accumulation of male-biased genes and the depletion of female-biased genes on the Z chromosome. Once this is accounted for, the Z chromosome is fully compensated in all four species, through the up-regulation of Z expression in females and in some cases additional down-regulation in males. We further find that both sex-biased genes and Z-linked genes have increased rates of expression divergence in this clade, and that this can lead to fast shifts in patterns of gene expression even between closely related species. Taken together, these results show that the uneven distribution of sex-biased genes on sex chromosomes can confound conclusions about dosage compensation and that Z chromosome-wide dosage compensation is not only possible but ubiquitous among Lepidoptera.
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Affiliation(s)
| | - Ariana Macon
- Institute of Science and Technology Austria, Klosterneuburg, Austria
| | - Beatriz Vicoso
- Institute of Science and Technology Austria, Klosterneuburg, Austria
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24
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Papa F, Windbichler N, Waterhouse RM, Cagnetti A, D'Amato R, Persampieri T, Lawniczak MKN, Nolan T, Papathanos PA. Rapid evolution of female-biased genes among four species of Anopheles malaria mosquitoes. Genome Res 2017; 27:1536-1548. [PMID: 28747381 PMCID: PMC5580713 DOI: 10.1101/gr.217216.116] [Citation(s) in RCA: 44] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2016] [Accepted: 07/18/2017] [Indexed: 01/09/2023]
Abstract
Understanding how phenotypic differences between males and females arise from the sex-biased expression of nearly identical genomes can reveal important insights into the biology and evolution of a species. Among Anopheles mosquito species, these phenotypic differences include vectorial capacity, as it is only females that blood feed and thus transmit human malaria. Here, we use RNA-seq data from multiple tissues of four vector species spanning the Anopheles phylogeny to explore the genomic and evolutionary properties of sex-biased genes. We find that, in these mosquitoes, in contrast to what has been found in many other organisms, female-biased genes are more rapidly evolving in sequence, expression, and genic turnover than male-biased genes. Our results suggest that this atypical pattern may be due to the combination of sex-specific life history challenges encountered by females, such as blood feeding. Furthermore, female propensity to mate only once in nature in male swarms likely diminishes sexual selection of post-reproductive traits related to sperm competition among males. We also develop a comparative framework to systematically explore tissue- and sex-specific splicing to document its conservation throughout the genus and identify a set of candidate genes for future functional analyses of sex-specific isoform usage. Finally, our data reveal that the deficit of male-biased genes on the X Chromosomes in Anopheles is a conserved feature in this genus and can be directly attributed to chromosome-wide transcriptional regulation that de-masculinizes the X in male reproductive tissues.
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Affiliation(s)
- Francesco Papa
- Section of Genomics and Genetics, Department of Experimental Medicine, University of Perugia, 06132 Perugia, Italy
| | - Nikolai Windbichler
- Department of Life Sciences, Imperial College London, SW7 2AZ London, United Kingdom
| | - Robert M Waterhouse
- University of Geneva Medical School and Swiss Institute of Bioinformatics, 1211 Geneva, Switzerland
- Massachusetts Institute of Technology and the Broad Institute of MIT and Harvard, Cambridge, Massachusetts 02139, USA
- Department of Ecology and Evolution, University of Lausanne, CH-1015 Lausanne, Switzerland
| | - Alessia Cagnetti
- Section of Genomics and Genetics, Department of Experimental Medicine, University of Perugia, 06132 Perugia, Italy
- Polo d'Innovazione di Genomica, Genetica e Biologia, 06132 Perugia, Italy
| | - Rocco D'Amato
- Section of Genomics and Genetics, Department of Experimental Medicine, University of Perugia, 06132 Perugia, Italy
| | - Tania Persampieri
- Section of Genomics and Genetics, Department of Experimental Medicine, University of Perugia, 06132 Perugia, Italy
- Polo d'Innovazione di Genomica, Genetica e Biologia, 06132 Perugia, Italy
| | | | - Tony Nolan
- Department of Life Sciences, Imperial College London, SW7 2AZ London, United Kingdom
| | - Philippos Aris Papathanos
- Section of Genomics and Genetics, Department of Experimental Medicine, University of Perugia, 06132 Perugia, Italy
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25
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Trizzino M, Park Y, Holsbach-Beltrame M, Aracena K, Mika K, Caliskan M, Perry GH, Lynch VJ, Brown CD. Transposable elements are the primary source of novelty in primate gene regulation. Genome Res 2017; 27:1623-1633. [PMID: 28855262 PMCID: PMC5630026 DOI: 10.1101/gr.218149.116] [Citation(s) in RCA: 143] [Impact Index Per Article: 20.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2016] [Accepted: 08/17/2017] [Indexed: 12/11/2022]
Abstract
Gene regulation shapes the evolution of phenotypic diversity. We investigated the evolution of liver promoters and enhancers in six primate species using ChIP-seq (H3K27ac and H3K4me1) to profile cis-regulatory elements (CREs) and using RNA-seq to characterize gene expression in the same individuals. To quantify regulatory divergence, we compared CRE activity across species by testing differential ChIP-seq read depths directly measured for orthologous sequences. We show that the primate regulatory landscape is largely conserved across the lineage, with 63% of the tested human liver CREs showing similar activity across species. Conserved CRE function is associated with sequence conservation, proximity to coding genes, cell-type specificity, and transcription factor binding. Newly evolved CREs are enriched in immune response and neurodevelopmental functions. We further demonstrate that conserved CREs bind master regulators, suggesting that while CREs contribute to species adaptation to the environment, core functions remain intact. Newly evolved CREs are enriched in young transposable elements (TEs), including Long-Terminal-Repeats (LTRs) and SINE-VNTR-Alus (SVAs), that significantly affect gene expression. Conversely, only 16% of conserved CREs overlap TEs. We tested the cis-regulatory activity of 69 TE subfamilies by luciferase reporter assays, spanning all major TE classes, and showed that 95.6% of tested TEs can function as either transcriptional activators or repressors. In conclusion, we demonstrated the critical role of TEs in primate gene regulation and illustrated potential mechanisms underlying evolutionary divergence among the primate species through the noncoding genome.
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Affiliation(s)
- Marco Trizzino
- Department of Genetics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania 19104, USA.,Institute for Biomedical Informatics, University of Pennsylvania, Philadelphia, Pennsylvania 19104, USA
| | - YoSon Park
- Department of Genetics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania 19104, USA.,Institute for Biomedical Informatics, University of Pennsylvania, Philadelphia, Pennsylvania 19104, USA
| | - Marcia Holsbach-Beltrame
- Department of Genetics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania 19104, USA
| | - Katherine Aracena
- Department of Genetics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania 19104, USA
| | - Katelyn Mika
- Department of Human Genetics, University of Chicago, Chicago, Illinois 60637, USA
| | - Minal Caliskan
- Department of Genetics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania 19104, USA.,Institute for Biomedical Informatics, University of Pennsylvania, Philadelphia, Pennsylvania 19104, USA
| | - George H Perry
- Departments of Anthropology and Biology, Pennsylvania State University, University Park, Pennsylvania 16802, USA
| | - Vincent J Lynch
- Department of Human Genetics, University of Chicago, Chicago, Illinois 60637, USA
| | - Christopher D Brown
- Department of Genetics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania 19104, USA.,Institute for Biomedical Informatics, University of Pennsylvania, Philadelphia, Pennsylvania 19104, USA
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26
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Casola C, Betrán E. The Genomic Impact of Gene Retrocopies: What Have We Learned from Comparative Genomics, Population Genomics, and Transcriptomic Analyses? Genome Biol Evol 2017; 9:1351-1373. [PMID: 28605529 PMCID: PMC5470649 DOI: 10.1093/gbe/evx081] [Citation(s) in RCA: 56] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/18/2017] [Indexed: 02/07/2023] Open
Abstract
Gene duplication is a major driver of organismal evolution. Gene retroposition is a mechanism of gene duplication whereby a gene's transcript is used as a template to generate retroposed gene copies, or retrocopies. Intriguingly, the formation of retrocopies depends upon the enzymatic machinery encoded by retrotransposable elements, genomic parasites occurring in the majority of eukaryotes. Most retrocopies are depleted of the regulatory regions found upstream of their parental genes; therefore, they were initially considered transcriptionally incompetent gene copies, or retropseudogenes. However, examples of functional retrocopies, or retrogenes, have accumulated since the 1980s. Here, we review what we have learned about retrocopies in animals, plants and other eukaryotic organisms, with a particular emphasis on comparative and population genomic analyses complemented with transcriptomic datasets. In addition, these data have provided information about the dynamics of the different "life cycle" stages of retrocopies (i.e., polymorphic retrocopy number variants, fixed retropseudogenes and retrogenes) and have provided key insights into the retroduplication mechanisms, the patterns and evolutionary forces at work during the fixation process and the biological function of retrogenes. Functional genomic and transcriptomic data have also revealed that many retropseudogenes are transcriptionally active and a biological role has been experimentally determined for many. Finally, we have learned that not only non-long terminal repeat retroelements but also long terminal repeat retroelements play a role in the emergence of retrocopies across eukaryotes. This body of work has shown that mRNA-mediated duplication represents a widespread phenomenon that produces an array of new genes that contribute to organismal diversity and adaptation.
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Affiliation(s)
- Claudio Casola
- Department of Ecosystem Science and Management, Texas A&M University, TX
| | - Esther Betrán
- Department of Biology, University of Texas at Arlington, Arlington, TX
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27
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Cassone BJ, Kay RGG, Daugherty MP, White BJ. Comparative Transcriptomics of Malaria Mosquito Testes: Function, Evolution, and Linkage. G3 (BETHESDA, MD.) 2017; 7:1127-1136. [PMID: 28159865 PMCID: PMC5386861 DOI: 10.1534/g3.117.040089] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/02/2016] [Accepted: 01/31/2017] [Indexed: 01/05/2023]
Abstract
Testes-biased genes evolve rapidly and are important in the establishment, solidification, and maintenance of reproductive isolation between incipient species. The Anopheles gambiae complex, a group of at least eight isomorphic mosquito species endemic to Sub-Saharan Africa, is an excellent system to explore the evolution of testes-biased genes. Within this group, the testes are an important tissue in the diversification process because hybridization between species results in sterile hybrid males, but fully fertile females. We conducted RNA sequencing of A. gambiae and A. merus carcass and testes to explore tissue- and species-specific patterns of gene expression. Our data provides support for transcriptional repression of X-linked genes in the male germline, which likely drives demasculinization of the X chromosome. Testes-biased genes predominately function in cellular differentiation and show a number of interesting patterns indicative of their rapid evolution, including elevated dN/dS values, low evolutionary conservation, poor annotation in existing reference genomes, and a high likelihood of differential expression between species.
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Affiliation(s)
- Bryan J Cassone
- Department of Biology, Brandon University, Manitoba R7A 6A9, Canada
| | - Raissa G G Kay
- Department of Entomology, University of California, Riverside, California 92521
- Graduate Program in Genetics, Genomics, and Bioinformatics, University of California, Riverside, California 92521
| | - Matthew P Daugherty
- Department of Entomology, University of California, Riverside, California 92521
| | - Bradley J White
- Department of Entomology, University of California, Riverside, California 92521
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28
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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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29
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Larson EL, Keeble S, Vanderpool D, Dean MD, Good JM. The Composite Regulatory Basis of the Large X-Effect in Mouse Speciation. Mol Biol Evol 2017; 34:282-295. [PMID: 27999113 PMCID: PMC6200130 DOI: 10.1093/molbev/msw243] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
The disruption of meiotic sex chromosome inactivation (MSCI) has been proposed to be a major developmental mechanism underlying the rapid evolution of hybrid male sterility. We tested this idea by analyzing cell-specific gene expression across spermatogenesis in two lineages of house mice and their sterile and fertile reciprocal hybrids. We found pervasive disruption of sex chromosome gene expression in sterile hybrids at every stage of spermatogenesis. Failure of MSCI was developmentally preceded by increased silencing of autosomal genes, supporting the hypothesis that divergence at the hybrid incompatibility gene, Prdm9, results in increased rates of autosomal asynapsis which in turn triggers widespread silencing of unsynapsed chromatin. We also detected opposite patterns of postmeiotic overexpression or hyper-repression of the sex chromosomes in reciprocal hybrids, supporting the hypothesis that genomic conflict has driven functional divergence that leads to deleterious X-Y dosage imbalances in hybrids. Our developmental timeline also exposed more subtle patterns of mitotic misregulation on the X chromosome, a previously undocumented stage of spermatogenic disruption in this cross. These results indicate that multiple hybrid incompatibilities have converged on a common regulatory phenotype, the disrupted expression of the sex chromosomes during spermatogenesis. Collectively, these data reveal a composite regulatory basis to hybrid male sterility in mice that helps resolve the mechanistic underpinnings of the well-documented large X-effect in mice speciation. We propose that the inherent sensitivity of spermatogenesis to X-linked regulatory disruption has the potential to be a major driver of reproductive isolation in species with chromosomal sex determination.
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Affiliation(s)
- Erica L Larson
- Division of Biological Sciences, University of Montana, Missoula, MT
| | - Sara Keeble
- Division of Biological Sciences, University of Montana, Missoula, MT
- Molecular and Computational Biology, University of Southern California, Los Angeles, CA
| | - Dan Vanderpool
- Division of Biological Sciences, University of Montana, Missoula, MT
| | - Matthew D Dean
- Molecular and Computational Biology, University of Southern California, Los Angeles, CA
| | - Jeffrey M Good
- Division of Biological Sciences, University of Montana, Missoula, MT
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30
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Affiliation(s)
- Lauren A. Richardson
- Public Library of Science, San Francisco, California, United States of America
- * E-mail:
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