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Jin J, Zhan Z, Wei X, Pan Z, Zhao Y, Yu D, Zhang F. Genomic insights into the chromosomal elongation in a family of Collembola. Proc Biol Sci 2024; 291:20232937. [PMID: 38471545 DOI: 10.1098/rspb.2023.2937] [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: 01/02/2024] [Accepted: 02/12/2024] [Indexed: 03/14/2024] Open
Abstract
Collembola is a highly diverse and abundant group of soil arthropods with chromosome numbers ranging from 5 to 11. Previous karyotype studies indicated that the Tomoceridae family possesses an exceptionally long chromosome. To better understand chromosome size evolution in Collembola, we obtained a chromosome-level genome of Yoshiicerus persimilis with a size of 334.44 Mb and BUSCO completeness of 97.0% (n = 1013). Both genomes of Y. persimilis and Tomocerus qinae (recently published) have an exceptionally large chromosome (ElChr greater than 100 Mb), accounting for nearly one-third of the genome. Comparative genomic analyses suggest that chromosomal elongation occurred independently in the two species approximately 10 million years ago, rather than in the ancestor of the Tomoceridae family. The ElChr elongation was caused by large tandem and segmental duplications, as well as transposon proliferation, with genes in these regions experiencing weaker purifying selection (higher dN/dS) than conserved regions. Moreover, inter-genomic synteny analyses indicated that chromosomal fission/fusion events played a crucial role in the evolution of chromosome numbers (ranging from 5 to 7) within Entomobryomorpha. This study provides a valuable resource for investigating the chromosome evolution of Collembola.
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Affiliation(s)
- Jianfeng Jin
- Department of Entomology, College of Plant Protection, Nanjing Agricultural University, Nanjing 210095, People's Republic of China
| | - Zhihong Zhan
- Department of Entomology, College of Plant Protection, Nanjing Agricultural University, Nanjing 210095, People's Republic of China
| | - Xiping Wei
- Department of Entomology, College of Plant Protection, Nanjing Agricultural University, Nanjing 210095, People's Republic of China
| | - Zhixiang Pan
- School of Life Sciences, Taizhou University, Taizhou 318000, People's Republic of China
| | - Yuxin Zhao
- Department of Entomology, College of Plant Protection, Nanjing Agricultural University, Nanjing 210095, People's Republic of China
| | - Daoyuan Yu
- Soil Ecology Lab, College of Resources and Environmental Sciences, Nanjing Agricultural University, Nanjing 210095, People's Republic of China
| | - Feng Zhang
- Department of Entomology, College of Plant Protection, Nanjing Agricultural University, Nanjing 210095, People's Republic of China
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2
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Wang S, Zhang Y, Yang W, Shen Y, Lin Z, Zhang S, Song G. Duplicate genes as sources for rapid adaptive evolution of sperm under environmental pollution in tree sparrow. Mol Ecol 2022; 32:1673-1684. [PMID: 36567644 DOI: 10.1111/mec.16833] [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: 08/20/2022] [Revised: 12/12/2022] [Accepted: 12/13/2022] [Indexed: 12/27/2022]
Abstract
Environmental pollution can result in poor sperm quality either directly or indirectly in birds. However, adaptive and compensatory sperm morphology changes and motility improvements have rapidly evolved in tree sparrows (Passer montanus) inhabiting polluted areas over the past 65 years. To identify the genetic underpinnings of the rapidly evolving sperm phenotype, we carried out population genomics and transcriptomics on tree sparrow populations in the two differently polluted places. We identified a gene encoding the serine/threonine protein kinase PIM1, which may drive rapid phenotypic evolution of sperm. An unprecedented and remarkable expansion of the PIM gene family, caused by tandem and segmental duplication of PIM1, was subsequently observed in the tree sparrow genome. Most PIM1 duplicates showed a testis-specific expression pattern, suggesting that their functions are related to male reproduction. Furthermore, the elevated expression level of PIM1 was consistent with our earlier findings of longer and faster swimming sperm in polluted sites, indicating an important role for duplicated PIM1 in facilitating the rapid evolution of sperm. Our results suggest that duplicated PIM1 provides sources of genetic variation that may enable the rapid evolution of sperm under environmental heavy metal pollution. The findings of this study indicated that duplicated genes can be targets of selection and predominant sources for rapid adaptation to environmental change and shed light on sperm evolution under pollution stress.
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Affiliation(s)
- Shengnan Wang
- Gansu Key Laboratory of Biomonitoring and Bioremediation for Environmental Pollution, School of Life Science, Lanzhou University, Lanzhou, China
| | - Yingmei Zhang
- Gansu Key Laboratory of Biomonitoring and Bioremediation for Environmental Pollution, School of Life Science, Lanzhou University, Lanzhou, China
| | - Wenzhi Yang
- Gansu Key Laboratory of Biomonitoring and Bioremediation for Environmental Pollution, School of Life Science, Lanzhou University, Lanzhou, China
| | - Yue Shen
- Gansu Key Laboratory of Biomonitoring and Bioremediation for Environmental Pollution, School of Life Science, Lanzhou University, Lanzhou, China
| | - Zhaocun Lin
- Gansu Key Laboratory of Biomonitoring and Bioremediation for Environmental Pollution, School of Life Science, Lanzhou University, Lanzhou, China
| | - Sheng Zhang
- Gansu Key Laboratory of Biomonitoring and Bioremediation for Environmental Pollution, School of Life Science, Lanzhou University, Lanzhou, China
| | - Gang Song
- Key Laboratory of Zoological Systematics and Evolution, Institute of Zoology, Chinese Academy of Science, Beijing, China
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3
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Enhanced Loss of Retinoic Acid Network Genes in Xenopus laevis Achieves a Tighter Signal Regulation. Cells 2022; 11:cells11030327. [PMID: 35159137 PMCID: PMC8834563 DOI: 10.3390/cells11030327] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2021] [Revised: 01/13/2022] [Accepted: 01/17/2022] [Indexed: 12/10/2022] Open
Abstract
Retinoic acid (RA) is a major regulatory signal during embryogenesis produced from vitamin A (retinol) by an extensive, autoregulating metabolic and signaling network to prevent fluctuations that result in developmental malformations. Xenopus laevis is an allotetraploid hybrid frog species whose genome includes L (long) and S (short) chromosomes from the originating species. Evolutionarily, the X. laevis subgenomes have been losing either L or S homoeologs in about 43% of genes to generate singletons. In the RA network, out of the 47 genes, about 47% have lost one of the homoeologs, like the genome average. Interestingly, RA metabolism genes from storage (retinyl esters) to retinaldehyde production exhibit enhanced gene loss with 75% singletons out of 28 genes. The effect of this gene loss on RA signaling autoregulation was studied. Employing transient RA manipulations, homoeolog gene pairs were identified in which one homoeolog exhibits enhanced responses or looser regulation than the other, while in other pairs both homoeologs exhibit similar RA responses. CRISPR/Cas9 targeting of individual homoeologs to reduce their activity supports the hypothesis where the RA metabolic network gene loss results in tighter network regulation and more efficient RA robustness responses to overcome complex regulation conditions.
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4
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Lineage-Specific Genes and Family Expansions in Dictyostelid Genomes Display Expression Bias and Evolutionary Diversification during Development. Genes (Basel) 2021; 12:genes12101628. [PMID: 34681022 PMCID: PMC8535579 DOI: 10.3390/genes12101628] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2021] [Revised: 10/12/2021] [Accepted: 10/13/2021] [Indexed: 12/23/2022] Open
Abstract
Gene duplications generate new genes that can contribute to expression changes and the evolution of new functions. Genomes often consist of gene families that undergo expansions, some of which occur in specific lineages that reflect recent adaptive diversification. In this study, lineage-specific genes and gene family expansions were studied across five dictyostelid species to determine when and how they are expressed during multicellular development. Lineage-specific genes were found to be enriched among genes with biased expression (predominant expression in one developmental stage) in each species and at most developmental time points, suggesting independent functional innovations of new genes throughout the phylogeny. Biased duplicate genes had greater expression divergence than their orthologs and paralogs, consistent with subfunctionalization or neofunctionalization. Lineage-specific expansions in particular had biased genes with both molecular signals of positive selection and high expression, suggesting adaptive genetic and transcriptional diversification following duplication. Our results present insights into the potential contributions of lineage-specific genes and families in generating species-specific phenotypes during multicellular development in dictyostelids.
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5
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Huang KM, Chain FJJ. Copy number variations and young duplicate genes have high methylation levels in sticklebacks. Evolution 2021; 75:706-718. [PMID: 33527399 DOI: 10.1111/evo.14184] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2020] [Revised: 01/19/2021] [Accepted: 01/25/2021] [Indexed: 12/11/2022]
Abstract
Gene duplication is an important driver of genomic diversity that can promote adaptive evolution. However, like most mutations, a newly duplicated gene is often deleterious and removed from the genome by drift or natural selection. The early molecular changes that occur soon after duplication therefore may influence the long-term survival of gene duplicates, but relatively little empirical data exist on the events near the onset of duplication before mutations have time to accumulate. In this study, we contrast gene expression and DNA methylation levels of duplicate genes in the threespine stickleback, Gasterosteus aculeatus, including recently emerged duplications that segregate as copy number variations (CNVs). We find that younger duplicate genes have higher levels of promoter methylation than older genes, and that gene CNVs have higher promoter methylation than non-CNVs. These results suggest preferential duplication of highly methylated genes or rapid methylation changes soon after duplication. We also find a negative association between methylation and expression, providing a putative role for methylation in suppressing transcription that compensates for increases in gene copy numbers and promoting paralog retention. We propose that methylation contributes to the longevity of young duplicate genes, extending the window of opportunity for functional divergence via mutation.
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Affiliation(s)
- Katherine M Huang
- Department of Biological Sciences, University of Massachusetts Lowell, Lowell, Massachusetts, 01854.,Comparative Media Studies/Writing, Massachusetts Institute of Technology, Cambridge, Massachusetts, 02139
| | - Frédéric J J Chain
- Department of Biological Sciences, University of Massachusetts Lowell, Lowell, Massachusetts, 01854
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6
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Evans BJ, Upham NS, Golding GB, Ojeda RA, Ojeda AA. Evolution of the Largest Mammalian Genome. Genome Biol Evol 2018; 9:1711-1724. [PMID: 28854639 PMCID: PMC5569995 DOI: 10.1093/gbe/evx113] [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] [Accepted: 06/21/2017] [Indexed: 12/31/2022] Open
Abstract
The genome of the red vizcacha rat (Rodentia, Octodontidae, Tympanoctomys barrerae) is the largest of all mammals, and about double the size of their close relative, the mountain vizcacha rat Octomys mimax, even though the lineages that gave rise to these species diverged from each other only about 5 Ma. The mechanism for this rapid genome expansion is controversial, and hypothesized to be a consequence of whole genome duplication or accumulation of repetitive elements. To test these alternative but nonexclusive hypotheses, we gathered and evaluated evidence from whole transcriptome and whole genome sequences of T. barrerae and O. mimax. We recovered support for genome expansion due to accumulation of a diverse assemblage of repetitive elements, which represent about one half and one fifth of the genomes of T. barrerae and O. mimax, respectively, but we found no strong signal of whole genome duplication. In both species, repetitive sequences were rare in transcribed regions as compared with the rest of the genome, and mostly had no close match to annotated repetitive sequences from other rodents. These findings raise new questions about the genomic dynamics of these repetitive elements, their connection to widespread chromosomal fissions that occurred in the T. barrerae ancestor, and their fitness effects—including during the evolution of hypersaline dietary tolerance in T. barrerae.
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Affiliation(s)
- Ben J Evans
- Biology Department, McMaster University, Hamilton, Ontario, Canada
| | - Nathan S Upham
- Biology Department, McMaster University, Hamilton, Ontario, Canada.,Field Museum of Natural History, Chicago, IL.,Department of Ecology and Evolutionary Biology, Yale University, New Haven, CT
| | | | - Ricardo A Ojeda
- Grupo de Investigaciones de la Biodiversidad (GIB), Instituto Argentino de Investigaciones de Zonas Áridas (IADIZA), Mendoza, Argentina
| | - Agustina A Ojeda
- Grupo de Investigaciones de la Biodiversidad (GIB), Instituto Argentino de Investigaciones de Zonas Áridas (IADIZA), Mendoza, Argentina
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7
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Krabbenhoft TJ, Turner TF. Comparative transcriptomics of cyprinid minnows and carp in a common wild setting: a resource for ecological genomics in freshwater communities. DNA Res 2018; 25:11-23. [PMID: 28985264 PMCID: PMC5824830 DOI: 10.1093/dnares/dsx034] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2017] [Accepted: 08/12/2017] [Indexed: 12/30/2022] Open
Abstract
Comparative transcriptomics can now be conducted on organisms in natural settings, which has greatly enhanced understanding of genome–environment interactions. Here, we demonstrate the utility and potential pitfalls of comparative transcriptomics of wild organisms, with an example from three cyprinid fish species (Teleostei:Cypriniformes). We present extensively filtered and annotated transcriptome assemblies that provide a valuable resource for studies of genome evolution (e.g. polyploidy), ecological and morphological diversification, speciation, and shared and unique responses to environmental variation in cyprinid fishes. Our results and analyses address the following points: (i) ‘essential developmental genes’ are shown to be ubiquitously expressed in a diverse suite of tissues across later ontogenetic stages (i.e. juveniles and adults), making these genes are useful for assessing the quality of transcriptome assemblies, (ii) the influence of microbiomes and other exogenous DNA, (iii) potentially novel, species-specific genes, and (iv) genomic rearrangements (e.g. whole genome duplication). The data we present provide a resource for future comparative work in cypriniform fishes and other taxa across a variety of sub-disciplines, including stress response, morphological diversification, community ecology, ecotoxicology, and climate change.
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Affiliation(s)
- Trevor J Krabbenhoft
- Department of Biology and Museum of Southwestern Biology, University of New Mexico, Albuquerque, NM 87131, USA
| | - Thomas F Turner
- Department of Biology and Museum of Southwestern Biology, University of New Mexico, Albuquerque, NM 87131, USA
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8
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Zhong L, Wang W. Homoeologous Recombination of the V1r1-V1r2 Gene Cluster of Pheromone Receptors in an Allotetraploid Lineage of Teleosts. Genes (Basel) 2017; 8:genes8110334. [PMID: 29160813 PMCID: PMC5704247 DOI: 10.3390/genes8110334] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2017] [Revised: 10/30/2017] [Accepted: 11/13/2017] [Indexed: 11/16/2022] Open
Abstract
In contrast to other olfactory receptor families that exhibit frequent lineage-specific expansions, the vomeronasal type 1 receptor (V1R) family exhibits a canonical six-member repertoire in teleosts. V1r1 and V1r2 are present in no more than one copy in all examined teleosts, including salmons, which are ancient polyploids, implying strict evolutionary constraints. However, recent polyploids have not been examined. Here, we identified a young allotetraploid lineage of weatherfishes and investigated their V1r1-V1r2 cluster. We found a novel pattern that the parental V1r1-V1r2 clusters had recombined in the tetraploid genome and that the recombinant was nearly fixed in the tetraploid population. Subsequent analyses suggested strong selective pressure, for both a new combination of paralogs and homogeneity among gene duplicates, acting on the V1r1-V1r2 pair.
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Affiliation(s)
- Lei Zhong
- Key Lab of Agricultural Animal Genetics, Breeding and Reproduction of Ministry of Education/Key Lab of Freshwater Animal Breeding of Ministry of Agriculture/Freshwater Aquaculture Collaborative Innovation Center of Hubei Province, College of Fisheries, Huazhong Agricultural University, Wuhan 430070, China.
| | - Weimin Wang
- Key Lab of Agricultural Animal Genetics, Breeding and Reproduction of Ministry of Education/Key Lab of Freshwater Animal Breeding of Ministry of Agriculture/Freshwater Aquaculture Collaborative Innovation Center of Hubei Province, College of Fisheries, Huazhong Agricultural University, Wuhan 430070, China.
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9
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Complex Genes Are Preferentially Retained After Whole-Genome Duplication in Teleost Fish. J Mol Evol 2017; 84:253-258. [PMID: 28492966 DOI: 10.1007/s00239-017-9794-8] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2017] [Accepted: 05/03/2017] [Indexed: 11/27/2022]
Abstract
Gene duplication generates new genetic material which, if retained after duplication, may contribute to organismal evolution. A whole-genome duplication occurred in the ancestry of teleost fish and consequently there are many duplicated genes in teleost genomes. Indeed, it has been proposed that the evolutionary diversification of teleost fish may have been stimulated by the fish-specific genome duplication (FSGD). However, it is not clear which factors determine which genes are retained as duplicate copies and which return to a singleton state after duplication. In the present study, gene complexity, in terms of encoded protein length and functional domain number, is compared between duplicate and singleton genes for nine well-annotated teleost genomes. A total of 933 gene families with retained duplicates and 4590 singleton gene families are analysed. Genes with retained duplicates are found to be significantly longer (27.9-38.2%) and to have more functional domains (20.5-26.5%) than singleton genes in all the nine teleost genomes, suggesting that genes encoded longer proteins with and more functional domains were preferentially retained after whole-genome duplication in teleosts. This differential retention of duplicated genes will have increased the genomic complexity of teleost fish after FSGD which, together with differential duplicated gene retention as a lineage-splitting force, may have greatly contributed to the successful diversification of teleost fish.
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10
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Session AM, Uno Y, Kwon T, Chapman JA, Toyoda A, Takahashi S, Fukui A, Hikosaka A, Suzuki A, Kondo M, van Heeringen SJ, Quigley I, Heinz S, Ogino H, Ochi H, Hellsten U, Lyons JB, Simakov O, Putnam N, Stites J, Kuroki Y, Tanaka T, Michiue T, Watanabe M, Bogdanovic O, Lister R, Georgiou G, Paranjpe SS, van Kruijsbergen I, Shu S, Carlson J, Kinoshita T, Ohta Y, Mawaribuchi S, Jenkins J, Grimwood J, Schmutz J, Mitros T, Mozaffari SV, Suzuki Y, Haramoto Y, Yamamoto TS, Takagi C, Heald R, Miller K, Haudenschild C, Kitzman J, Nakayama T, Izutsu Y, Robert J, Fortriede J, Burns K, Lotay V, Karimi K, Yasuoka Y, Dichmann DS, Flajnik MF, Houston DW, Shendure J, DuPasquier L, Vize PD, Zorn AM, Ito M, Marcotte EM, Wallingford JB, Ito Y, Asashima M, Ueno N, Matsuda Y, Veenstra GJC, Fujiyama A, Harland RM, Taira M, Rokhsar DS. Genome evolution in the allotetraploid frog Xenopus laevis. Nature 2016; 538:336-343. [PMID: 27762356 PMCID: PMC5313049 DOI: 10.1038/nature19840] [Citation(s) in RCA: 634] [Impact Index Per Article: 79.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/25/2015] [Accepted: 09/09/2016] [Indexed: 02/07/2023]
Abstract
To explore the origins and consequences of tetraploidy in the African clawed frog, we sequenced the Xenopus laevis genome and compared it to the related diploid X. tropicalis genome. We demonstrate the allotetraploid origin of X. laevis by partitioning its genome into two homeologous subgenomes, marked by distinct families of “fossil” transposable elements. Based on the activity of these elements and the age of hundreds of unitary pseudogenes, we estimate that the two diploid progenitor species diverged ~34 million years ago (Mya) and combined to form an allotetraploid ~17–18 Mya. 56% of all genes are retained in two homeologous copies. Protein function, gene expression, and the amount of flanking conserved sequence all correlate with retention rates. The subgenomes have evolved asymmetrically, with one chromosome set more often preserving the ancestral state and the other experiencing more gene loss, deletion, rearrangement, and reduced gene expression.
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Affiliation(s)
- Adam M Session
- University of California, Berkeley, Department of Molecular and Cell Biology and Center for Integrative Genomics, Life Sciences Addition #3200, Berkeley, California 94720-3200, USA.,US Department of Energy Joint Genome Institute, Walnut Creek, California 94598, USA
| | - Yoshinobu Uno
- Department of Applied Molecular Biosciences, Graduate School of Bioagricultural Sciences, Nagoya University, Furo-cho, Chikusa-ku, Nagoya, Aichi 464-8601, Japan
| | - Taejoon Kwon
- Department of Molecular Biosciences, Center for Systems and Synthetic Biology, University of Texas at Austin, Austin, Texas 78712, USA.,Department of Biomedical Engineering, School of Life Sciences, Ulsan National Institute of Science and Technology, Ulsan 689-798, Republic of Korea
| | - Jarrod A Chapman
- US Department of Energy Joint Genome Institute, Walnut Creek, California 94598, USA
| | - Atsushi Toyoda
- Center for Information Biology, and Advanced Genomics Center, National Institute of Genetics, 1111 Yata, Mishima, Shizuoka 411-8540, Japan
| | - Shuji Takahashi
- Amphibian Research Center, Graduate School of Science, Hiroshima University, 1-3-1 Kagamiyama, Higashi-Hiroshima, Hiroshima 739-8526, Japan
| | - Akimasa Fukui
- Laboratory of Tissue and Polymer Sciences, Faculty of Advanced Life Science, Hokkaido University, N10W8, Kita-ku, Sapporo 060-0810, Japan
| | - Akira Hikosaka
- Division of Human Sciences, Graduate School of Integrated Arts and Sciences, Hiroshima University, 1-7-1 Kagamiyama, Higashi-Hiroshima, Hiroshima 739-8521, Japan
| | - Atsushi Suzuki
- Amphibian Research Center, Graduate School of Science, Hiroshima University, 1-3-1 Kagamiyama, Higashi-Hiroshima, Hiroshima 739-8526, Japan
| | - Mariko Kondo
- Misaki Marine Biological Station (MMBS), Graduate School of Science, The University of Tokyo, 1024 Koajiro, Misaki, Miura, Kanagawa 238-0225, Japan
| | - Simon J van Heeringen
- Radboud University, Faculty of Science, Department of Molecular Developmental Biology, 259 RIMLS, M850/2.97, Geert Grooteplein 28, Nijmegen 6525 GA, the Netherlands
| | - Ian Quigley
- Salk Institute, Molecular Neurobiology Laboratory, La Jolla, San Diego, California 92037, USA
| | - Sven Heinz
- Salk Institute for Biological Studies, 10010 North Torrey Pines Road, La Jolla, San Diego, California 92037, USA
| | - Hajime Ogino
- Department of Animal Bioscience, Nagahama Institute of Bio-Science and Technology, 1266 Tamura, Nagahama, Shiga 526-0829, Japan
| | - Haruki Ochi
- Institute for Promotion of Medical Science Research, Yamagata University Faculty of Medicine, 2-2-2 Iida-Nishi, Yamagata, Yamagata 990-9585, Japan
| | - Uffe Hellsten
- US Department of Energy Joint Genome Institute, Walnut Creek, California 94598, USA
| | - Jessica B Lyons
- University of California, Berkeley, Department of Molecular and Cell Biology and Center for Integrative Genomics, Life Sciences Addition #3200, Berkeley, California 94720-3200, USA
| | - Oleg Simakov
- Molecular Genetics Unit, Okinawa Institute of Science and Technology Graduate University, Onna, Okinawa 904-0495, Japan
| | | | | | - Yoko Kuroki
- Department of Genome Medicine, National Research Institute for Child Health and Development, NCCHD, 2-10-1, Okura, Setagaya-ku, Tokyo 157-8535, Japan
| | - Toshiaki Tanaka
- Department of Life Science and Technology, Tokyo Institute of Technology, 4259 Nagatsuta, Midori-ku, Yokohama 226-8501, Japan
| | - Tatsuo Michiue
- Department of Life Sciences, Graduate School of Arts and Sciences, The University of Tokyo, 3-8-1, Komaba, Meguro-ku, Tokyo 153-8902, Japan
| | - Minoru Watanabe
- Institute of Institution of Liberal Arts and Fundamental Education, Tokushima University, 1-1 Minamijosanjima-cho, Tokushima 770-8502, Japan
| | - Ozren Bogdanovic
- Harry Perkins Institute of Medical Research and ARC Centre of Excellence in Plant Energy Biology, The University of Western Australia, Perth, Western Australia 6009, Australia
| | - Ryan Lister
- Harry Perkins Institute of Medical Research and ARC Centre of Excellence in Plant Energy Biology, The University of Western Australia, Perth, Western Australia 6009, Australia
| | - Georgios Georgiou
- Radboud University, Faculty of Science, Department of Molecular Developmental Biology, 259 RIMLS, M850/2.97, Geert Grooteplein 28, Nijmegen 6525 GA, the Netherlands
| | - Sarita S Paranjpe
- Radboud University, Faculty of Science, Department of Molecular Developmental Biology, 259 RIMLS, M850/2.97, Geert Grooteplein 28, Nijmegen 6525 GA, the Netherlands
| | - Ila van Kruijsbergen
- Radboud University, Faculty of Science, Department of Molecular Developmental Biology, 259 RIMLS, M850/2.97, Geert Grooteplein 28, Nijmegen 6525 GA, the Netherlands
| | - Shengquiang Shu
- US Department of Energy Joint Genome Institute, Walnut Creek, California 94598, USA
| | - Joseph Carlson
- US Department of Energy Joint Genome Institute, Walnut Creek, California 94598, USA
| | - Tsutomu Kinoshita
- Department of Life Science, Faculty of Science, Rikkyo University, 3-34-1 Nishi-Ikebukuro, Toshima-ku, Tokyo 171-8501, Japan
| | - Yuko Ohta
- Department of Microbiology and Immunology, University of Maryland, 655 W Baltimore St, Baltimore, Maryland 21201, USA
| | - Shuuji Mawaribuchi
- Kitasato Institute for Life Sciences, Kitasato University, 5-9-1 Shirokane Minato-ku, Tokyo 108-8641, Japan
| | - Jerry Jenkins
- US Department of Energy Joint Genome Institute, Walnut Creek, California 94598, USA.,HudsonAlpha Institute of Biotechnology, Huntsville, Alabama 35806, USA
| | - Jane Grimwood
- US Department of Energy Joint Genome Institute, Walnut Creek, California 94598, USA.,HudsonAlpha Institute of Biotechnology, Huntsville, Alabama 35806, USA
| | - Jeremy Schmutz
- US Department of Energy Joint Genome Institute, Walnut Creek, California 94598, USA.,HudsonAlpha Institute of Biotechnology, Huntsville, Alabama 35806, USA
| | - Therese Mitros
- University of California, Berkeley, Department of Molecular and Cell Biology and Center for Integrative Genomics, Life Sciences Addition #3200, Berkeley, California 94720-3200, USA
| | - Sahar V Mozaffari
- Department of Human Genetics, University of Chicago, 920 E. 58th St, CLSC 431F, Chicago, Illinois 60637, USA
| | - Yutaka Suzuki
- Department of Computational Biology and Medical Sciences, The University of Tokyo, 5-1-5 Kashiwanoha, Kashiwa-shi, Chiba 277-8568, Japan
| | - Yoshikazu Haramoto
- Biotechnology Research Institute for Drug Discovery, National Institute of Advanced Industrial Science and Technology (AIST), Central 5, 1-1-1 Higashi, Tsukuba, Ibaraki 305-8565, Japan
| | - Takamasa S Yamamoto
- Division of Morphogenesis, Department of Developmental Biology, National Institute for Basic Biology, 38 Nishigonaka, Myodaiji, Okazaki, Aichi 444-8585, Japan
| | - Chiyo Takagi
- Division of Morphogenesis, Department of Developmental Biology, National Institute for Basic Biology, 38 Nishigonaka, Myodaiji, Okazaki, Aichi 444-8585, Japan
| | - Rebecca Heald
- University of California, Berkeley, Department of Molecular and Cell Biology, Life Sciences Addition #3200, Berkeley California 94720-3200, USA
| | - Kelly Miller
- University of California, Berkeley, Department of Molecular and Cell Biology, Life Sciences Addition #3200, Berkeley California 94720-3200, USA
| | | | - Jacob Kitzman
- Department of Genome Sciences, University of Washington, Foege Building S-250, Box 355065, 3720 15th Ave NE, Seattle Washington 98195-5065, USA
| | - Takuya Nakayama
- Department of Biology, University of Virginia, Charlottesville, Virginia 22904, USA
| | - Yumi Izutsu
- Department of Biology, Faculty of Science, Niigata University, 8050, Ikarashi 2-no-cho, Nishi-ku, Niigata 950-2181, Japan
| | - Jacques Robert
- Department of Microbiology &Immunology, University of Rochester Medical Center, Rochester, New York 14642, USA
| | - Joshua Fortriede
- Division of Developmental Biology, Cincinnati Children's Research Foundation, Cincinnati, Ohio 45229-3039, USA
| | - Kevin Burns
- Division of Developmental Biology, Cincinnati Children's Research Foundation, Cincinnati, Ohio 45229-3039, USA
| | - Vaneet Lotay
- Department of Biological Sciences, University of Calgary, Alberta T2N 1N4, Canada
| | - Kamran Karimi
- Department of Biological Sciences, University of Calgary, Alberta T2N 1N4, Canada
| | - Yuuri Yasuoka
- Marine Genomics Unit, Okinawa Institute of Science and Technology Graduate University, 1919-1 Tancha, Onna-son, Okinawa 904-0495, Japan
| | - Darwin S Dichmann
- University of California, Berkeley, Department of Molecular and Cell Biology and Center for Integrative Genomics, Life Sciences Addition #3200, Berkeley, California 94720-3200, USA
| | - Martin F Flajnik
- Department of Microbiology and Immunology, University of Maryland, 655 W Baltimore St, Baltimore, Maryland 21201, USA
| | - Douglas W Houston
- The University of Iowa, Department of Biology, 257 Biology Building, Iowa City, Iowa 52242-1324, USA
| | - Jay Shendure
- Department of Genome Sciences, University of Washington, Foege Building S-250, Box 355065, 3720 15th Ave NE, Seattle Washington 98195-5065, USA
| | - Louis DuPasquier
- Department of Zoology and Evolutionary Biology, University of Basel, Basel CH-4051, Switzerland
| | - Peter D Vize
- Department of Biological Sciences, University of Calgary, Alberta T2N 1N4, Canada
| | - Aaron M Zorn
- Division of Developmental Biology, Cincinnati Children's Research Foundation, Cincinnati, Ohio 45229-3039, USA
| | - Michihiko Ito
- Department of Biological Sciences, School of Science, Kitasato University, 1-15-1 Minamiku, Sagamihara, Kanagawa 252-0373, Japan
| | - Edward M Marcotte
- Department of Molecular Biosciences, Center for Systems and Synthetic Biology, University of Texas at Austin, Austin, Texas 78712, USA
| | - John B Wallingford
- Department of Molecular Biosciences, Center for Systems and Synthetic Biology, University of Texas at Austin, Austin, Texas 78712, USA
| | - Yuzuru Ito
- Biotechnology Research Institute for Drug Discovery, National Institute of Advanced Industrial Science and Technology (AIST), Central 5, 1-1-1 Higashi, Tsukuba, Ibaraki 305-8565, Japan
| | - Makoto Asashima
- Biotechnology Research Institute for Drug Discovery, National Institute of Advanced Industrial Science and Technology (AIST), Central 5, 1-1-1 Higashi, Tsukuba, Ibaraki 305-8565, Japan
| | - Naoto Ueno
- Division of Morphogenesis, Department of Developmental Biology, National Institute for Basic Biology, 38 Nishigonaka, Myodaiji, Okazaki, Aichi 444-8585, Japan.,Department of Basic Biology, SOKENDAI (The Graduate University for Advanced Studies), 38 Nishigonaka, Myodaiji, Okazaki, Aichi 444-8585, Japan
| | - Yoichi Matsuda
- Department of Applied Molecular Biosciences, Graduate School of Bioagricultural Sciences, Nagoya University, Furo-cho, Chikusa-ku, Nagoya, Aichi 464-8601, Japan
| | - Gert Jan C Veenstra
- Radboud University, Faculty of Science, Department of Molecular Developmental Biology, 259 RIMLS, M850/2.97, Geert Grooteplein 28, Nijmegen 6525 GA, the Netherlands
| | - Asao Fujiyama
- Center for Information Biology, and Advanced Genomics Center, National Institute of Genetics, 1111 Yata, Mishima, Shizuoka 411-8540, Japan.,Principles of Informatics, National Institute of Informatics, 2-1-2 Hitotsubashi, Chiyoda-ku, Tokyo 101-8430, Japan.,Department of Genetics, SOKENDAI (The Graduate University for Advanced Studies), 1111 Yata, Mishima, Shizoka 411-8540, Japan
| | - Richard M Harland
- University of California, Berkeley, Department of Molecular and Cell Biology and Center for Integrative Genomics, Life Sciences Addition #3200, Berkeley, California 94720-3200, USA
| | - Masanori Taira
- Department of Biological Sciences, Graduate School of Science, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan
| | - Daniel S Rokhsar
- University of California, Berkeley, Department of Molecular and Cell Biology and Center for Integrative Genomics, Life Sciences Addition #3200, Berkeley, California 94720-3200, USA.,US Department of Energy Joint Genome Institute, Walnut Creek, California 94598, USA.,Molecular Genetics Unit, Okinawa Institute of Science and Technology Graduate University, Onna, Okinawa 904-0495, Japan
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11
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Pophaly SD, Tellier A. Population Level Purifying Selection and Gene Expression Shape Subgenome Evolution in Maize. Mol Biol Evol 2015; 32:3226-35. [PMID: 26374232 DOI: 10.1093/molbev/msv191] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
The maize ancestor experienced a recent whole-genome duplication (WGD) followed by gene erosion which generated two subgenomes, the dominant subgenome (maize1) experiencing fewer deletions than maize2. We take advantage of available extensive polymorphism and gene expression data in maize to study purifying selection and gene expression divergence between WGD retained paralog pairs. We first report a strong correlation in nucleotide diversity between duplicate pairs, except for upstream regions. We then show that maize1 genes are under stronger purifying selection than maize2. WGD retained genes have higher gene dosage and biased Gene Ontologies consistent with previous studies. The relative gene expression of paralogs across tissues demonstrates that 98% of duplicate pairs have either subfunctionalized in a tissuewise manner or have diverged consistently in their expression thereby preventing functional complementation. Tissuewise subfunctionalization seems to be a hallmark of transcription factors, whereas consistent repression occurs for macromolecular complexes. We show that dominant gene expression is a strong determinant of the strength of purifying selection, explaining the inferred stronger negative selection on maize1 genes. We propose a novel expression-based classification of duplicates which is more robust to explain observed polymorphism patterns than the subgenome location. Finally, upstream regions of repressed genes exhibit an enrichment in transposable elements which indicates a possible mechanism for expression divergence.
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Affiliation(s)
- Saurabh D Pophaly
- Section of Population Genetics, School of Life Sciences Weihenstephan, Technische Universität München, Freising, Germany
| | - Aurélien Tellier
- Section of Population Genetics, School of Life Sciences Weihenstephan, Technische Universität München, Freising, Germany
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12
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Mable BK, Kilbride E, Viney ME, Tinsley RC. Copy number variation and genetic diversity of MHC Class IIb alleles in an alien population of Xenopus laevis. Immunogenetics 2015; 67:591-603. [PMID: 26329765 PMCID: PMC4572066 DOI: 10.1007/s00251-015-0860-3] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2015] [Accepted: 07/10/2015] [Indexed: 12/23/2022]
Abstract
Xenopus laevis (the African clawed frog), which originated through hybridisation and whole genome duplication, has been used as a model for genetics and development for many years, but surprisingly little is known about immune gene variation in natural populations. The purpose of this study was to use an isolated population of X. laevis that was introduced to Wales, UK in the past 50 years to investigate how variation at the MHC compares to that at other loci, following a severe population bottleneck. Among 18 individuals, we found nine alleles based on exon 2 sequences of the Class IIb region (which includes the peptide binding region). Individuals carried from one to three of the loci identified from previous laboratory studies. Genetic variation was an order of magnitude higher at the MHC compared with three single-copy nuclear genes, but all loci showed high levels of heterozygosity and nucleotide diversity and there was not an excess of homozygosity or decrease in diversity over time that would suggest extensive inbreeding in the introduced population. Tajima’s D was positive for all loci, which is consistent with a bottleneck. Moreover, comparison with published sequences identified the source of the introduced population as the Western Cape region of South Africa, where most commercial suppliers have obtained their stocks. These factors suggest that despite founding by potentially already inbred individuals, the alien population in Wales has maintained substantial genetic variation at both adaptively important and neutral genes.
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Affiliation(s)
- Barbara K Mable
- Institute of Biodiversity, Animal Health & Comparative Medicine, College of Medical, Veterinary & Life Sciences, University of Glasgow, Glasgow, G12 8QQ, UK.
| | - Elizabeth Kilbride
- Institute of Biodiversity, Animal Health & Comparative Medicine, College of Medical, Veterinary & Life Sciences, University of Glasgow, Glasgow, G12 8QQ, UK
| | - Mark E Viney
- School of Biological Sciences, University of Bristol, Bristol, BS8 1TQ, UK.
| | - Richard C Tinsley
- School of Biological Sciences, University of Bristol, Bristol, BS8 1TQ, UK
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13
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Evans BJ, Schmid M. Preface. Cytogenet Genome Res 2015. [PMID: 26202694 DOI: 10.1159/000437176] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
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14
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Schüler A, Schmitz G, Reft A, Özbek S, Thurm U, Bornberg-Bauer E. The Rise and Fall of TRP-N, an Ancient Family of Mechanogated Ion Channels, in Metazoa. Genome Biol Evol 2015; 7:1713-27. [PMID: 26100409 PMCID: PMC4494053 DOI: 10.1093/gbe/evv091] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Mechanoreception, the sensing of mechanical forces, is an ancient means of orientation and communication and tightly linked to the evolution of motile animals. In flies, the transient-receptor-potential N protein (TRP-N) was found to be a cilia-associated mechanoreceptor. TRP-N belongs to a large and diverse family of ion channels. Its unusually long N-terminal repeat of 28 ankyrin domains presumably acts as the gating spring by which mechanical energy induces channel gating. We analyzed the evolutionary origins and possible diversification of TRP-N. Using a custom-made set of highly discriminative sequence profiles we scanned a representative set of metazoan genomes and subsequently corrected several gene models. We find that, contrary to other ion channel families, TRP-N is remarkably conserved in its domain arrangements and copy number (1) in all Bilateria except for amniotes, even in the wake of several whole-genome duplications. TRP-N is absent in Porifera but present in Ctenophora and Placozoa. Exceptional multiplications of TRP-N occurred in Cnidaria, independently along the Hydra and the Nematostella lineage. Molecular signals of subfunctionalization can be attributed to different mechanisms of activation of the gating spring. In Hydra this is further supported by in situ hybridization and immune staining, suggesting that at least three paralogs adapted to nematocyte discharge, which is key for predation and defense. We propose that these new candidate proteins help explain the sensory complexity of Cnidaria which has been previously observed but so far has lacked a molecular underpinning. Also, the ancient appearance of TRP-N supports a common origin of important components of the nervous systems in Ctenophores, Cnidaria, and Bilateria.
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Affiliation(s)
- Andreas Schüler
- Institute for Evolution and Biodiversity, University of Muenster, Germany
| | - Gregor Schmitz
- Institute for Evolution and Biodiversity, University of Muenster, Germany
| | - Abigail Reft
- Centre for Organismal Studies, University of Heidelberg, Germany
| | - Suat Özbek
- Centre for Organismal Studies, University of Heidelberg, Germany HEIKA-Heidelberg Karlsruhe Research Partnership, Heidelberg University, Karlsruhe Institute of Technology (KIT), Heidelberg and Karlsruhe, Germany
| | - Ulrich Thurm
- Institute for Neurobiology and Behavioural Biology, University of Muenster, Germany
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15
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Kwon T. Benchmarking Transcriptome Quantification Methods for Duplicated Genes in Xenopus laevis. Cytogenet Genome Res 2015; 145:253-64. [DOI: 10.1159/000431386] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
Xenopus is an important model organism for the study of genome duplication in vertebrates. With the full genome sequence of diploid Xenopus tropicalis available, and that of allotetraploid X. laevis close to being finished, we will be able to expand our understanding of how duplicated genes have evolved. One of the key features in the study of the functional consequence of gene duplication is how their expression patterns vary across different conditions, and RNA-seq seems to have enough resolution to discriminate the expression of highly similar duplicated genes. However, most of the current RNA-seq analysis methods were not designed to study samples with duplicate genes such as in X. laevis. Here, various computational methods to quantify gene expression in RNA-seq data were evaluated, using 2 independent X. laevis egg RNA-seq datasets and 2 reference databases for duplicated genes. The fact that RNA-seq can measure expression levels of similar duplicated genes was confirmed, but long paired-end reads are more informative than short single-end reads to discriminate duplicated genes. Also, it was found that bowtie, one of the most popular mappers in RNA-seq analysis, reports significantly smaller numbers of unique hits according to a mapping quality score compared to other mappers tested (BWA, GSNAP, STAR). Calculated from unique hits based on a mapping quality score, both expression levels and the expression ratio of duplicated genes can be estimated consistently among biological replicates, demonstrating that this method can successfully discriminate the expression of each copy of a duplicated gene pair. This comprehensive evaluation will be a useful guideline for studying gene expression of organisms with genome duplication using RNA-seq in the future.
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16
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Evans BJ, Kwon T. Molecular Polymorphism and Divergence of Duplicated Genes in Tetraploid African Clawed Frogs (Xenopus). Cytogenet Genome Res 2015; 145:243-52. [PMID: 26066830 DOI: 10.1159/000431108] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
Genome duplication creates redundancy in proteins and their interaction networks, and subsequent smaller-scale gene duplication can further amplify genetic redundancy. Mutations then lead to the loss, maintenance or functional divergence of duplicated genes. Genome duplication occurred many times in African clawed frogs (genus Xenopus), and almost all extant species in this group evolved from a polyploid ancestor. To better understand the nature of selective constraints in a polyploid genome, we examined molecular polymorphism and divergence of duplicates and single-copy genes in 2 tetraploid African clawed frog species, Xenopus laevis and X. victorianus. We found that molecular polymorphism in the coding regions of putative duplicated genes was higher than in singletons, but not significantly so. Our findings also suggest that transcriptome evolution in polyploids is influenced by variation in the genome-wide mutation rate, and do not reject the hypothesis that gene dosage balance is also important.
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Affiliation(s)
- Ben J Evans
- Department of Biology, McMaster University, Hamilton, Ont., Canada
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17
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Lambert MJ, Cochran WO, Wilde BM, Olsen KG, Cooper CD. Evidence for widespread subfunctionalization of splice forms in vertebrate genomes. Genome Res 2015; 25:624-32. [PMID: 25792610 PMCID: PMC4417111 DOI: 10.1101/gr.184473.114] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2014] [Accepted: 03/16/2015] [Indexed: 11/24/2022]
Abstract
Gene duplication and alternative splicing are important sources of proteomic diversity. Despite research indicating that gene duplication and alternative splicing are negatively correlated, the evolutionary relationship between the two remains unclear. One manner in which alternative splicing and gene duplication may be related is through the process of subfunctionalization, in which an alternatively spliced gene upon duplication divides distinct splice isoforms among the newly generated daughter genes, in this way reducing the number of alternatively spliced transcripts duplicate genes produce. Previously, it has been shown that splice form subfunctionalization will result in duplicate pairs with divergent exon structure when distinct isoforms become fixed in each paralog. However, the effects of exon structure divergence between paralogs have never before been studied on a genome-wide scale. Here, using genomic data from human, mouse, and zebrafish, we demonstrate that gene duplication followed by exon structure divergence between paralogs results in a significant reduction in levels of alternative splicing. In addition, by comparing the exon structure of zebrafish duplicates to the co-orthologous human gene, we have demonstrated that a considerable fraction of exon divergent duplicates maintain the structural signature of splice form subfunctionalization. Furthermore, we find that paralogs with divergent exon structure demonstrate reduced breadth of expression in a variety of tissues when compared to paralogs with identical exon structures and singletons. Taken together, our results are consistent with subfunctionalization partitioning alternatively spliced isoforms among duplicate genes and as such highlight the relationship between gene duplication and alternative splicing.
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Affiliation(s)
- Matthew J Lambert
- School of Biological Sciences, Washington State University, Pullman, Washington 99164, USA
| | - Wayne O Cochran
- School of Engineering and Computer Science, Washington State University Vancouver, Vancouver, Washington 98686, USA
| | - Brandon M Wilde
- College of Arts and Sciences, Washington State University Vancouver, Vancouver, Washington 98686, USA
| | - Kyle G Olsen
- College of Arts and Sciences, Washington State University Vancouver, Vancouver, Washington 98686, USA
| | - Cynthia D Cooper
- School of Biological Sciences, Washington State University, Pullman, Washington 99164, USA; School of Molecular Biosciences, Washington State University, Pullman, Washington 99164, USA
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18
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Furman BLS, Bewick AJ, Harrison TL, Greenbaum E, Gvoždík V, Kusamba C, Evans BJ. Pan-African phylogeography of a model organism, the African clawed frog 'Xenopus laevis'. Mol Ecol 2015; 24:909-25. [PMID: 25583226 DOI: 10.1111/mec.13076] [Citation(s) in RCA: 43] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2014] [Revised: 01/06/2015] [Accepted: 01/08/2015] [Indexed: 11/30/2022]
Abstract
The African clawed frog Xenopus laevis has a large native distribution over much of sub-Saharan Africa and is a model organism for research, a proposed disease vector, and an invasive species. Despite its prominent role in research and abundance in nature, surprisingly little is known about the phylogeography and evolutionary history of this group. Here, we report an analysis of molecular variation of this clade based on 17 loci (one mitochondrial, 16 nuclear) in up to 159 individuals sampled throughout its native distribution. Phylogenetic relationships among mitochondrial DNA haplotypes were incongruent with those among alleles of the putatively female-specific sex-determining gene DM-W, in contrast to the expectation of strict matrilineal inheritance of both loci. Population structure and evolutionarily diverged lineages were evidenced by analyses of molecular variation in these data. These results further contextualize the chronology, and evolutionary relationships within this group, support the recognition of X. laevis sensu stricto, X. petersii, X. victorianus and herein revalidated X. poweri as separate species. We also propose that portions of the currently recognized distributions of X. laevis (north of the Congo Basin) and X. petersii (south of the Congo Basin) be reassigned to X. poweri.
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Affiliation(s)
- Benjamin L S Furman
- Biology Department, McMaster University, Life Sciences Building, 1280 Main Street West, Hamilton, Ontario, Canada, L8S 4K1
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19
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Transcriptome-wide analysis of SAMe superfamily to novelty phosphoethanolamine N-methyltransferase copy in Lonicera japonica. Int J Mol Sci 2014; 16:521-34. [PMID: 25551601 PMCID: PMC4307260 DOI: 10.3390/ijms16010521] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2014] [Accepted: 11/24/2014] [Indexed: 01/01/2023] Open
Abstract
The S-adenosyl-L-methionine-dependent methyltransferase superfamily plays important roles in plant development. The buds of Lonicera japonica are used as Chinese medical material and foods; chinese people began domesticating L. japonica thousands of years ago. Compared to the wild species, L. japonica var. chinensis, L. japonica gives a higher yield of buds, a fact closely related to positive selection over the long cultivation period of the species. Genome duplications, which are always detected in the domestic species, are the source of the multifaceted roles of the functional gene. In this paper, we investigated the evolution of the SAMe genes in L. japonica and L. japonica var. chinensis and further analyzed the roles of the duplicated genes among special groups. The SAMe protein sequences were subdivided into three clusters and several subgroups. The difference in transcriptional levels of the duplicated genes showed that seven SAMe genes could be related to the differences between the wild and the domesticated varieties. The sequence diversity of seven SAMe genes was also analyzed, and the results showed that different gene expression levels between the varieties could not be related to amino acid variation. The transcriptional level of duplicated PEAMT could be regulated through the SAM-SAH cycle.
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20
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Glasauer SMK, Neuhauss SCF. Whole-genome duplication in teleost fishes and its evolutionary consequences. Mol Genet Genomics 2014; 289:1045-60. [PMID: 25092473 DOI: 10.1007/s00438-014-0889-2] [Citation(s) in RCA: 513] [Impact Index Per Article: 51.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2013] [Accepted: 07/15/2014] [Indexed: 12/18/2022]
Abstract
Whole-genome duplication (WGD) events have shaped the history of many evolutionary lineages. One such duplication has been implicated in the evolution of teleost fishes, by far the most species-rich vertebrate clade. After initial controversy, there is now solid evidence that such event took place in the common ancestor of all extant teleosts. It is termed teleost-specific (TS) WGD. After WGD, duplicate genes have different fates. The most likely outcome is non-functionalization of one duplicate gene due to the lack of selective constraint on preserving both. Mechanisms that act on preservation of duplicates are subfunctionalization (partitioning of ancestral gene functions on the duplicates), neofunctionalization (assigning a novel function to one of the duplicates) and dosage selection (preserving genes to maintain dosage balance between interconnected components). Since the frequency of these mechanisms is influenced by the genes' properties, there are over-retained classes of genes, such as highly expressed ones and genes involved in neural function. The consequences of the TS-WGD, especially its impact on the massive radiation of teleosts, have been matter of controversial debate. It is evident that gene duplications are crucial for generating complexity and that WGDs provide large amounts of raw material for evolutionary adaptation and innovation. However, it is less clear whether the TS-WGD is directly linked to the evolutionary success of teleosts and their radiation. Recent studies let us conclude that TS-WGD has been important in generating teleost complexity, but that more recent ecological adaptations only marginally related to TS-WGD might have even contributed more to diversification. It is likely, however, that TS-WGD provided teleosts with diversification potential that can become effective much later, such as during phases of environmental change.
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Affiliation(s)
- Stella M K Glasauer
- Institute of Molecular Life Sciences, University of Zurich, Winterthurerstrasse 190, 8057, Zurich, Switzerland
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21
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Yampolsky LY, Bouzinier MA. Faster evolving Drosophila paralogs lose expression rate and ubiquity and accumulate more non-synonymous SNPs. Biol Direct 2014; 9:2. [PMID: 24438455 PMCID: PMC3906896 DOI: 10.1186/1745-6150-9-2] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2013] [Accepted: 01/07/2014] [Indexed: 12/31/2022] Open
Abstract
Background Duplicated genes can indefinately persist in genomes if either both copies retain the original function due to dosage benefit (gene conservation), or one of the copies assumes a novel function (neofunctionalization), or both copies become required to perform the function previously accomplished by a single copy (subfunctionalization), or through a combination of these mechanisms. Different models of duplication retention imply different predictions about substitution rates in the coding portion of paralogs and about asymmetry of these rates. Results We analyse sequence evolution asymmetry in paralogs present in 12 Drosophila genomes using the nearest non-duplicated orthologous outgroup as a reference. Those paralogs present in D. melanogaster are analysed in conjunction with the asymmetry of expression rate and ubiquity and of segregating non-synonymous polymorphisms in the same paralogs. Paralogs accumulate substitutions, on average, faster than their nearest singleton orthologs. The distribution of paralogs’ substitution rate asymmetry is overdispersed relative to that of orthologous clades, containing disproportionally more unusually symmetric and unusually asymmetric clades. We show that paralogs are more asymmetric in: a) clades orthologous to highly constrained singleton genes; b) genes with high expression level; c) genes with ubiquitous expression and d) non-tandem duplications. We further demonstrate that, in each asymmetrically evolving pair of paralogs, the faster evolving member of the pair tends to have lower average expression rate, lower expression uniformity and higher frequency of non-synonymous SNPs than its slower evolving counterpart. Conclusions Our findings are consistent with the hypothesis that many duplications in Drosophila are retained despite stabilising selection being more relaxed in one of the paralogs than in the other, suggesting a widespread unfinished pseudogenization. This phenomenon is likely to make detection of neo- and subfunctionalization signatures difficult, as these models of duplication retention also predict asymmetries in substitution rates and expression profiles. Reviewers This article has been reviewed by Dr. Jia Zeng (nominated by Dr. I. King Jordan), Dr. Fyodor Kondrashov and Dr. Yuri Wolf.
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Affiliation(s)
- Lev Y Yampolsky
- Department of Biological sciences, East Tennessee State University, Johnson City, TN 37614, USA.
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22
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Bewick AJ, Chain FJJ, Zimmerman LB, Sesay A, Gilchrist MJ, Owens NDL, Seifertova E, Krylov V, Macha J, Tlapakova T, Kubickova S, Cernohorska H, Zarsky V, Evans BJ. A large pseudoautosomal region on the sex chromosomes of the frog Silurana tropicalis. Genome Biol Evol 2013; 5:1087-98. [PMID: 23666865 PMCID: PMC3698919 DOI: 10.1093/gbe/evt073] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
Sex chromosome divergence has been documented across phylogenetically diverse species, with amphibians typically having cytologically nondiverged (“homomorphic”) sex chromosomes. With an aim of further characterizing sex chromosome divergence of an amphibian, we used “RAD-tags” and Sanger sequencing to examine sex specificity and heterozygosity in the Western clawed frog Silurana tropicalis (also known as Xenopus tropicalis). Our findings based on approximately 20 million genotype calls and approximately 200 polymerase chain reaction-amplified regions across multiple male and female genomes failed to identify a substantially sized genomic region with genotypic hallmarks of sex chromosome divergence, including in regions known to be tightly linked to the sex-determining region. We also found that expression and molecular evolution of genes linked to the sex-determining region did not differ substantially from genes in other parts of the genome. This suggests that the pseudoautosomal region, where recombination occurs, comprises a large portion of the sex chromosomes of S. tropicalis. These results may in part explain why African clawed frogs have such a high incidence of polyploidization, shed light on why amphibians have a high rate of sex chromosome turnover, and raise questions about why homomorphic sex chromosomes are so prevalent in amphibians.
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Affiliation(s)
- Adam J Bewick
- Department of Biology, McMaster University, Hamilton, Ontario, Canada
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23
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Zheng C, Chen E, Albert VA, Lyons E, Sankoff D. Ancient eudicot hexaploidy meets ancestral eurosid gene order. BMC Genomics 2013; 14 Suppl 7:S3. [PMID: 24564362 PMCID: PMC3817805 DOI: 10.1186/1471-2164-14-s7-s3] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND A hexaploidization event over 125 Mya underlies the evolutionary lineage of the majority of flowering plants, including very many species of agricultural importance. Half of these belong to the rosid subgrouping, containing severals whose genome sequences have been published. Although most duplicate and triplicate genes have been lost in all descendants, clear traces of the original chromosome triples can be discerned, their internal contiguity highly conserved in some genomes and very fragmented in others. To understand the particular evolutionary patterns of plant genomes, there is a need to systematically survey the fate of the subgenomes of polyploids, including the retention of a small proportion of the duplicate and triplicate genes and the reconstruction of putative ancestral intermediates between the original hexaploid and modern species, in this case the ancestor of the eurosid clade. RESULTS We quantitatively trace the fate of gene triples originating in the hexaploidy across seven core eudicot flowering plants, and fit this to a two-stage model, pre- and post-radiation. We also measure the simultaneous dynamics of duplicate orthologous gene loss in three rosids, as influenced by biological functional class. We propose a new protocol for reconstructing ancestral gene order using only gene adjacency data from pairwise genomic analyses, based on repeating MAXIMUM WEIGHT MATCHING at two levels of resolution, an approach designed to transcend limitations on reconstructed contig size, while still avoiding the ambiguities of a multiplicity of solutions. Applied to three high-quality rosid genomes without subsequent polyploidy events, our automated procedure reconstructs the ancestor of the eurosid clade. CONCLUSIONS The gene loss analysis and the ancestor reconstruction present complementary assessments of post-hexaploidization evolution, the first at the level of individual gene families within and across sister genomes and the second at the chromosome level. Despite the loss of more than 95% of gene duplicates and triplicates, and despite major structural rearrangement, our reconstructed eurosid ancestor clearly identifies the three regions corresponding to each of the seven original chromosomes of the earlier pre-hexaploid ancestor. Functional analysis confirmed trends reported for more recent plant polyploidy events: genes involved with regulation and responses were retained in multiple copies, while genes involved with metabolic processes were lost.
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Affiliation(s)
- Chunfang Zheng
- Department of Mathematics and Statistics, University of Ottawa, 585 King Edward Avenue, Ottawa, Canada K1N 6N5
| | - Eric Chen
- Department of Biology, University of Ottawa, 30 Marie-Curie, Ottawa, Canada K1N 6N5
| | - Victor A Albert
- Department of Biological Sciences, University at Buffalo, Buffalo, NY 14260, USA
| | - Eric Lyons
- School of Plant Sciences, University of Arizona, 1140 E. South Campus Drive, Tucson, AZ 85721, USA
| | - David Sankoff
- Department of Mathematics and Statistics, University of Ottawa, 585 King Edward Avenue, Ottawa, Canada K1N 6N5
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24
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Bogart JP, Bi K. Genetic and genomic interactions of animals with different ploidy levels. Cytogenet Genome Res 2013; 140:117-36. [PMID: 23751376 DOI: 10.1159/000351593] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
Polyploid animals have independently evolved from diploids in diverse taxa across the tree of life. We review a few polyploid animal species or biotypes where recently developed molecular and cytogenetic methods have significantly improved our understanding of their genetics, reproduction and evolution. Mitochondrial sequences that target the maternal ancestor of a polyploid show that polyploids may have single (e.g. unisexual salamanders in the genus Ambystoma) or multiple (e.g. parthenogenetic polyploid lizards in the genus Aspidoscelis) origins. Microsatellites are nuclear markers that can be used to analyze genetic recombinations, reproductive modes (e.g. Ambystoma) and recombination events (e.g. polyploid frogs such as Pelophylax esculentus). Hom(e)ologous chromosomes and rare intergenomic exchanges in allopolyploids have been distinguished by applying genome-specific fluorescent probes to chromosome spreads. Polyploids arise, and are maintained, through perturbations of the 'normal' meiotic program that would include pre-meiotic chromosome replication and genomic integrity of homologs. When possible, asexual, unisexual and bisexual polyploid species or biotypes interact with diploid relatives, and genes are passed from diploid to polyploid gene pools, which increase genetic diversity and ultimately evolutionary flexibility in the polyploid. When diploid relatives do not exist, polyploids can interact with another polyploid (e.g. species of African Clawed Frogs in the genus Xenopus). Some polyploid fish (e.g. salmonids) and frogs (Xenopus) represent independent lineages whose ancestors experienced whole genome duplication events. Some tetraploid frogs (P. esculentus) and fish (Squaliusalburnoides) may be in the process of becoming independent species, but diploid and triploid forms of these 'species' continue to genetically interact with the comparatively few tetraploid populations. Genetic and genomic interaction between polyploids and diploids is a complex and dynamic process that likely plays a crucial role for the evolution and persistence of polyploid animals. See also other articles in this themed issue.
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Affiliation(s)
- J P Bogart
- Department of Integrative Biology, University of Guelph, Guelph, Ont., Canada. jbogart @ uoguelph.ca
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25
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Shen JJ, Dushoff J, Bewick AJ, Chain FJ, Evans BJ. Genomic dynamics of transposable elements in the western clawed frog (Silurana tropicalis). Genome Biol Evol 2013; 5:998-1009. [PMID: 23645600 PMCID: PMC3673623 DOI: 10.1093/gbe/evt065] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 04/18/2013] [Indexed: 02/07/2023] Open
Abstract
Transposable elements (TEs) are repetitive DNA sequences that can make new copies of themselves that are inserted elsewhere in a host genome. The abundance and distributions of TEs vary considerably among phylogenetically diverse hosts. With the aim of exploring the basis of this variation, we evaluated correlations between several genomic variables and the presence of TEs and non-TE repeats in the complete genome sequence of the Western clawed frog (Silurana tropicalis). This analysis reveals patterns of TE insertion consistent with gene disruption but not with the insertional preference model. Analysis of non-TE repeats recovered unique features of their genome-wide distribution when compared with TE repeats, including no strong correlation with exons and a particularly strong negative correlation with GC content. We also collected polymorphism data from 25 TE insertion sites in 19 wild-caught S. tropicalis individuals. DNA transposon insertions were fixed at eight of nine sites and at a high frequency at one of nine, whereas insertions of long terminal repeat (LTR) and non-LTR retrotransposons were fixed at only 4 of 16 sites and at low frequency at 12 of 16. A maximum likelihood model failed to attribute these differences in insertion frequencies to variation in selection pressure on different classes of TE, opening the possibility that other phenomena such as variation in rates of replication or duration of residence in the genome could play a role. Taken together, these results identify factors that sculpt heterogeneity in TE distribution in S. tropicalis and illustrate that genomic dynamics differ markedly among TE classes and between TE and non-TE repeats.
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Affiliation(s)
- Jiangshan J. Shen
- Department of Biology, McMaster University, Hamilton, Ontario, Canada
- Present address: Department of Pathology, The University of Hong Kong, Hong Kong, China
| | - Jonathan Dushoff
- Department of Biology, McMaster University, Hamilton, Ontario, Canada
| | - Adam J. Bewick
- Department of Biology, McMaster University, Hamilton, Ontario, Canada
| | - Frédéric J.J. Chain
- Department of Evolutionary Ecology, Max Planck Institute for Evolutionary Biology, Plön, Germany
| | - Ben J. Evans
- Department of Biology, McMaster University, Hamilton, Ontario, Canada
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26
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Wertheim B, Beukeboom L, van de Zande L. Polyploidy in Animals: Effects of Gene Expression on Sex Determination, Evolution and Ecology. Cytogenet Genome Res 2013; 140:256-69. [DOI: 10.1159/000351998] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
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Affiliation(s)
- Adam J. Bewick
- Department of Biology, Life Sciences Building Room 328, McMaster University, 1280 Main Street West Hamilton, ON L8S 4K1, Canada
| | - Frédéric J. J. Chain
- Department of Biology, Life Sciences Building Room 328, McMaster University, 1280 Main Street West Hamilton, ON L8S 4K1, Canada
- Present address: Department of Evolutionary Ecology, Max Planck Institute for Evolutionary Biology, August-Thienemann-Str. 2, 24306 Plön, Germany
| | - Joseph Heled
- Department of Computer Science, University of Auckland, Auckland 1142, New Zealand
| | - Ben J. Evans
- Department of Biology, Life Sciences Building Room 328, McMaster University, 1280 Main Street West Hamilton, ON L8S 4K1, Canada
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