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de Sousa E Souza JF, Guimarães EMC, Figliuolo VSP, Soares SC, de Bello Cioffi M, de Menezes Cavalcante Sassi F, Feldberg E. Chromosomal mapping of repetitive DNA and retroelement sequences and its implications for the chromosomal evolution process in Ctenoluciidae (Characiformes). BMC Ecol Evol 2024; 24:72. [PMID: 38816840 PMCID: PMC11138015 DOI: 10.1186/s12862-024-02262-x] [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: 10/03/2023] [Accepted: 05/22/2024] [Indexed: 06/01/2024] Open
Abstract
Ctenoluciidae is a Neotropical freshwater fish family composed of two genera, Ctenolucius (C. beani and C. hujeta) and Boulengerella (B. cuvieri, B. lateristriga, B. lucius, B. maculata, and B. xyrekes), which present diploid number conservation of 36 chromosomes and a strong association of telomeric sequences with ribosomal DNAs. In the present study, we performed chromosomal mapping of microsatellites and transposable elements (TEs) in Boulengerella species and Ctenolucius hujeta. We aim to understand how those sequences are distributed in these organisms' genomes and their influence on the chromosomal evolution of the group. Our results indicate that repetitive sequences may had an active role in the karyotypic diversification of this family, especially in the formation of chromosomal hotspots that are traceable in the diversification processes of Ctenoluciidae karyotypes. We demonstrate that (GATA)n sequences also accumulate in the secondary constriction formed by the 18 S rDNA site, which shows consistent size heteromorphism between males and females in all Boulengerella species, suggesting an initial process of sex chromosome differentiation.
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Grants
- 573976/2008-2 Center for Studies of Adaptation to Environmental Changes in the Amazon (INCT ADAPTA II, FAPEAM/CNPq
- 573976/2008-2 Center for Studies of Adaptation to Environmental Changes in the Amazon (INCT ADAPTA II, FAPEAM/CNPq
- 573976/2008-2 Center for Studies of Adaptation to Environmental Changes in the Amazon (INCT ADAPTA II, FAPEAM/CNPq
- 573976/2008-2 Center for Studies of Adaptation to Environmental Changes in the Amazon (INCT ADAPTA II, FAPEAM/CNPq
- 301886/2019-9 Conselho Nacional de Desenvolvimento Científico e Tecnológico , Brasil
- 301886/2019-9 Conselho Nacional de Desenvolvimento Científico e Tecnológico , Brasil
- 301886/2019-9 Conselho Nacional de Desenvolvimento Científico e Tecnológico , Brasil
- 301886/2019-9 Conselho Nacional de Desenvolvimento Científico e Tecnológico , Brasil
- 301886/2019-9 Conselho Nacional de Desenvolvimento Científico e Tecnológico , Brasil
- 301886/2019-9 Conselho Nacional de Desenvolvimento Científico e Tecnológico , Brasil
- National Institute of Amazonian Research, Brazil/PPG Genetics, Conservation and Evolutionary Biology (INPA/GCBEv)
- Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)
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Affiliation(s)
- José Francisco de Sousa E Souza
- Conservation and Evolutionary Biology, INPA, National Amazon Research Institute, Av. André Araújo, 2936, Petrópolis, CEP: 69067-375, Caixa Postal 2223, Manaus, 69060-001, Amazonas, Brazil.
| | - Erika Milena Corrêa Guimarães
- Conservation and Evolutionary Biology, INPA, National Amazon Research Institute, Av. André Araújo, 2936, Petrópolis, CEP: 69067-375, Caixa Postal 2223, Manaus, 69060-001, Amazonas, Brazil
| | - Vanessa Susan Pinheiro Figliuolo
- Conservation and Evolutionary Biology, INPA, National Amazon Research Institute, Av. André Araújo, 2936, Petrópolis, CEP: 69067-375, Caixa Postal 2223, Manaus, 69060-001, Amazonas, Brazil
| | - Simone Cardoso Soares
- Conservation and Evolutionary Biology, INPA, National Amazon Research Institute, Av. André Araújo, 2936, Petrópolis, CEP: 69067-375, Caixa Postal 2223, Manaus, 69060-001, Amazonas, Brazil
| | - Marcelo de Bello Cioffi
- Department of Genetics and Evolution, Federal University of São Carlos, São Carlos, SP, Brazil
| | | | - Eliana Feldberg
- Conservation and Evolutionary Biology, INPA, National Amazon Research Institute, Av. André Araújo, 2936, Petrópolis, CEP: 69067-375, Caixa Postal 2223, Manaus, 69060-001, Amazonas, Brazil
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Haerter CAG, Blanco DR, Traldi JB, Feldberg E, Margarido VP, Lui RL. Are scattered microsatellites weak chromosomal markers? Guided mapping reveals new insights into Trachelyopterus (Siluriformes: Auchenipteridae) diversity. PLoS One 2023; 18:e0285388. [PMID: 37310952 DOI: 10.1371/journal.pone.0285388] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2022] [Accepted: 04/22/2023] [Indexed: 06/15/2023] Open
Abstract
The scattered distribution pattern of microsatellites is a challenging problem in fish cytogenetics. This type of array hinders the identification of useful patterns and the comparison between species, often resulting in over-limited interpretations that only label it as "scattered" or "widely distributed". However, several studies have shown that the distribution pattern of microsatellites is non-random. Thus, here we tested whether a scattered microsatellite could have distinct distribution patterns on homeologous chromosomes of closely related species. The clustered sites of 18S and 5S rDNA, U2 snRNA and H3/H4 histone genes were used as a guide to compare the (GATA)n microsatellite distribution pattern on the homeologous chromosomes of six Trachelyopterus species: T. coriaceus and Trachelyopterus aff. galeatus from the Araguaia River basin; T. striatulus, T. galeatus and T. porosus from the Amazonas River basin; and Trachelyopterus aff. coriaceus from the Paraguay River basin. Most species had similar patterns of the (GATA)n microsatellite in the histone genes and 5S rDNA carriers. However, we have found a chromosomal polymorphism of the (GATA)n sequence in the 18S rDNA carriers of Trachelyopterus galeatus, which is in Hard-Weinberg equilibrium and possibly originated through amplification events; and a chromosome polymorphism in Trachelyopterus aff. galeatus, which combined with an inversion polymorphism of the U2 snRNA in the same chromosome pair resulted in six possible cytotypes, which are in Hardy-Weinberg disequilibrium. Therefore, comparing the distribution pattern on homeologous chromosomes across the species, using gene clusters as a guide to identify it, seems to be an effective way to further the analysis of scattered microsatellites in fish cytogenetics.
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Affiliation(s)
| | | | - Josiane Baccarin Traldi
- Departamento de Genética, Instituto de Ciências Biológicas, Universidade Federal do Amazonas, Manaus, Brasil
| | | | - Vladimir Pavan Margarido
- Universidade Estadual do Oeste do Paraná, Centro de Ciências Biológicas e da Saúde, Cascavel, Paraná, Brasil
| | - Roberto Laridondo Lui
- Universidade Estadual do Oeste do Paraná, Centro de Ciências Biológicas e da Saúde, Cascavel, Paraná, Brasil
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3
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Cytogenetic Analysis of Seven Species of Gekkonid and Phyllodactylid Geckos. Genes (Basel) 2023; 14:genes14010178. [PMID: 36672918 PMCID: PMC9859368 DOI: 10.3390/genes14010178] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2022] [Revised: 12/24/2022] [Accepted: 01/04/2023] [Indexed: 01/11/2023] Open
Abstract
Geckos (Gekkota), the species-rich clade of reptiles with more than 2200 currently recognized species, demonstrate a remarkable variability in diploid chromosome numbers (2n = 16-48) and mode of sex determination. However, only a small fraction of gekkotan species have been studied with cytogenetic methods. Here, we applied both conventional (karyotype reconstruction and C-banding) and molecular (fluorescence in situ hybridization with probes for rDNA loci and telomeric repeats) cytogenetic analyses in seven species of geckos, namely Blaesodactylus boivini, Chondrodactylus laevigatus, Gekko badenii, Gekko cf. lionotum, Hemidactylus sahgali, Homopholis wahlbergii (Gekkonidae) and Ptyodactylus togoensis (Phyllodactylidae), in order to provide further insights into the evolution of karyotypes in geckos. Our analysis revealed the presence of interstitial telomeric repeats in four species, but we were not able to conclude if they are remnants of previous chromosome rearrangements or were formed by an accumulation of telomeric-like satellite motifs. Even though sex chromosomes were previously identified in several species from the genera Hemidactylus and Gekko by cytogenetic and/or genomic methods, they were not detected by us in any examined species. Our examined species either have poorly differentiated sex chromosomes or, possibly, environmental sex determination. Future studies should explore the effect of temperature and conduct genome-wide analyses in order to identify the mode of sex determination in these species.
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Kostmann A, Kratochvíl L, Rovatsos M. ZZ/ZW Sex Chromosomes in the Madagascar Girdled Lizard, Zonosaurus madagascariensis (Squamata: Gerrhosauridae). Genes (Basel) 2022; 14:genes14010099. [PMID: 36672840 PMCID: PMC9859402 DOI: 10.3390/genes14010099] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2022] [Revised: 12/23/2022] [Accepted: 12/26/2022] [Indexed: 12/31/2022] Open
Abstract
Scincoidea, the reptilian clade that includes girdled lizards, night lizards, plated lizards and skinks, are considered as a lineage with diversity in sex-determining systems. Recently, the hypothesis on the variability in sex determination in skinks and even more the absence of sex chromosomes in some of them has been rivalling. Homologous, evolutionary stable XX/XY sex chromosomes were documented to be widespread across skinks. However, sex determination in the other scincoidean families is highly understudied. ZZ/ZW sex chromosomes have been identified only in night lizards and a single species of plated lizards. It seems that although there are different sex chromosome systems among scincoidean lineages, they share one common trait: they are mostly poorly differentiated and often undetectable by cytogenetic methods. Here, we report one of the exceptions, demonstrating for the first time ZZ/ZW sex chromosomes in the plated lizard Zonosaurus madagascariensis. Its sex chromosomes are morphologically similar, but the W is clearly detectable by comparative genomic hybridization (CGH), suggesting that the Z and W chromosomes highly differ in sequence content. Our findings confirm the presence of female heterogamety in plated lizards and provides novel insights to expand our understanding of sex chromosome evolution in scincoidean lizards.
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Streeting LM, Bower DS, Dillon ML, Spark P, Gough M, Skidmore A, McDonald PG, Delaney H, Burns A, Watson S, Dissanayake DSB, Georges A, McKnight DT. Optimising the hatching success of artificially incubated eggs for use in a conservation program for the western saw-shelled turtle (. AUST J ZOOL 2022. [DOI: 10.1071/zo22014] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Artificial incubation of eggs and the release of hatchlings into the wild is a common conservation intervention designed to augment threatened turtle populations. We investigate a range of incubation temperatures to establish an optimal temperature for maximum hatching success of western saw-shelled turtle (Myuchelys bellii) eggs. We report on the influence of incubation temperature on incubation duration and hatching success and describe two experimental incubation methods which, for the same incubation temperature (27°C), resulted in 77% and 97% hatching success, respectively. Eggs were incubated at constant temperatures (27°C, 28°C and 29°C) to determine the influence of temperature on incubation period, hatchling morphology and external residual yolk. Incubation duration was negatively correlated with incubation temperature. We report on the morphology of eggs and hatchlings and show that their dimensions are positively correlated with maternal adult size and mass. A constant incubation temperature of 27°C produced the highest hatching success and smallest external residual yolk on hatching and is therefore recommended for incubation of eggs for population reinforcement programs. Our study is the first to optimise artificial incubation procedures for M. bellii and will be a valuable resource for M. bellii and other threatened freshwater turtle conservation initiatives.
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6
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Cytogenetic Analysis of the Members of the Snake Genera Cylindrophis, Eryx, Python, and Tropidophis. Genes (Basel) 2022; 13:genes13071185. [PMID: 35885968 PMCID: PMC9318745 DOI: 10.3390/genes13071185] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2022] [Revised: 06/25/2022] [Accepted: 06/28/2022] [Indexed: 02/06/2023] Open
Abstract
The recent discovery of two independently evolved XX/XY sex determination systems in the snake genera Python and Boa sparked a new drive to study the evolution of sex chromosomes in poorly studied lineages of snakes, where female heterogamety was previously assumed. Therefore, we examined seven species from the genera Eryx, Cylindrophis, Python, and Tropidophis by conventional and molecular cytogenetic methods. Despite the fact that these species have similar karyotypes in terms of chromosome number and morphology, we detected variability in the distribution of heterochromatin, telomeric repeats, and rDNA loci. Heterochromatic blocks were mainly detected in the centromeric regions in all species, although accumulations were detected in pericentromeric and telomeric regions in a few macrochromosomes in several of the studied species. All species show the expected topology of telomeric repeats at the edge of all chromosomes, with the exception of Eryx muelleri, where additional accumulations were detected in the centromeres of three pairs of macrochromosomes. The rDNA loci accumulate in one pair of microchromosomes in all Eryx species and in Cylindrophis ruffus, in one macrochromosome pair in Tropidophis melanurus and in two pairs of microchromosomes in Python regius. Sex-specific differences were not detected, suggesting that these species likely have homomorphic, poorly differentiated sex chromosomes.
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7
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Viana PF, Feldberg E, Takagui FH, Menezes S, Vogt RC, Ezaz T. Matamatas Chelus spp. (Testudines, Chelidae) have a remarkable evolutionary history of sex chromosomes with a long-term stable XY microchromosome system. Sci Rep 2022; 12:6676. [PMID: 35461353 PMCID: PMC9035145 DOI: 10.1038/s41598-022-10782-z] [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: 02/15/2022] [Accepted: 04/11/2022] [Indexed: 11/26/2022] Open
Abstract
The genus Chelus, commonly known as Matamata is one of the most emblematic and remarkable species among the Neotropical chelids. It is an Amazonian species with an extensive distribution throughout Negro/Orinoco and Amazonas River basins. Currently, two species are formally recognized: Chelus orinocensis and Chelus fimbriata and although it is still classified as "Least Concern" in the IUCN, the Matamatas are very appreciated and illegally sold in the international pet trade. Regardless, little is known regarding many aspects of its natural history. Chromosomal features for Chelus, for instance, are meagre and practically restricted to the description of the diploid number (2n = 50) for Chelus fimbriata, and its sex determining strategies are yet to be fully investigated. Here, we examined the karyotype of Chelus fimbriata and the newly described Chelus orinocensis, applying an extensive conventional and molecular cytogenetic approach. This allowed us to identify a genetic sex determining mechanism with a micro XY sex chromosome system in both species, a system that was likely present in their most common recent ancestor Chelus colombiana. Furthermore, the XY system found in Chelus orinocensis and Chelus fimbriata, as seen in other chelid species, recruited several repeat motifs, possibly prior to the split of South America and Australasian lineages, indicating that such system indeed dates back to the earliest lineages of Chelid species.
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Affiliation(s)
- Patrik F Viana
- Coordenação de Biodiversidade, Laboratory of Animal Genetics, Instituto Nacional de Pesquisas da Amazônia, Av. André Araújo 2936, Petrópolis, Manaus, AM, CEP: 69067-375, Brazil.
| | - Eliana Feldberg
- Coordenação de Biodiversidade, Laboratory of Animal Genetics, Instituto Nacional de Pesquisas da Amazônia, Av. André Araújo 2936, Petrópolis, Manaus, AM, CEP: 69067-375, Brazil
| | - Fábio Hiroshi Takagui
- Animal Cytogenetics Laboratory, Department of General Biology, CCB, Londrina State University, Londrina, Brazil
| | - Sabrina Menezes
- Coordenação de Biodiversidade, Centro de Estudos de Quelônios da Amazônia, Instituto Nacional de Pesquisas da Amazônia, Av. André Araújo 2936, Petrópolis, Manaus, AM, CEP: 69067-375, Brazil
| | - Richard C Vogt
- Coordenação de Biodiversidade, Centro de Estudos de Quelônios da Amazônia, Instituto Nacional de Pesquisas da Amazônia, Av. André Araújo 2936, Petrópolis, Manaus, AM, CEP: 69067-375, Brazil
| | - Tariq Ezaz
- Institute for Applied Ecology, Faculty of Science and Technology, University of Canberra, Canberra, ACT, 12 2616, Australia
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Sex Chromosomes and Master Sex-Determining Genes in Turtles and Other Reptiles. Genes (Basel) 2021; 12:genes12111822. [PMID: 34828428 PMCID: PMC8622242 DOI: 10.3390/genes12111822] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2021] [Revised: 11/12/2021] [Accepted: 11/16/2021] [Indexed: 11/24/2022] Open
Abstract
Among tetrapods, the well differentiated heteromorphic sex chromosomes of birds and mammals have been highly investigated and their master sex-determining (MSD) gene, Dmrt1 and SRY, respectively, have been identified. The homomorphic sex chromosomes of reptiles have been the least studied, but the gap with birds and mammals has begun to fill. This review describes our current knowledge of reptilian sex chromosomes at the cytogenetic and molecular level. Most of it arose recently from various studies comparing male to female gene content. This includes restriction site-associated DNA sequencing (RAD-Seq) experiments in several male and female samples, RNA sequencing and identification of Z- or X-linked genes by male/female comparative transcriptome coverage, and male/female transcriptomic or transcriptome/genome substraction approaches allowing the identification of Y- or W-linked transcripts. A few putative master sex-determining (MSD) genes have been proposed, but none has been demonstrated yet. Lastly, future directions in the field of reptilian sex chromosomes and their MSD gene studies are considered.
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Stöck M, Kratochvíl L, Kuhl H, Rovatsos M, Evans BJ, Suh A, Valenzuela N, Veyrunes F, Zhou Q, Gamble T, Capel B, Schartl M, Guiguen Y. A brief review of vertebrate sex evolution with a pledge for integrative research: towards ' sexomics'. Philos Trans R Soc Lond B Biol Sci 2021; 376:20200426. [PMID: 34247497 PMCID: PMC8293304 DOI: 10.1098/rstb.2020.0426] [Citation(s) in RCA: 25] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 03/08/2021] [Indexed: 02/07/2023] Open
Abstract
Triggers and biological processes controlling male or female gonadal differentiation vary in vertebrates, with sex determination (SD) governed by environmental factors or simple to complex genetic mechanisms that evolved repeatedly and independently in various groups. Here, we review sex evolution across major clades of vertebrates with information on SD, sexual development and reproductive modes. We offer an up-to-date review of divergence times, species diversity, genomic resources, genome size, occurrence and nature of polyploids, SD systems, sex chromosomes, SD genes, dosage compensation and sex-biased gene expression. Advances in sequencing technologies now enable us to study the evolution of SD at broader evolutionary scales, and we now hope to pursue a sexomics integrative research initiative across vertebrates. The vertebrate sexome comprises interdisciplinary and integrated information on sexual differentiation, development and reproduction at all biological levels, from genomes, transcriptomes and proteomes, to the organs involved in sexual and sex-specific processes, including gonads, secondary sex organs and those with transcriptional sex-bias. The sexome also includes ontogenetic and behavioural aspects of sexual differentiation, including malfunction and impairment of SD, sexual differentiation and fertility. Starting from data generated by high-throughput approaches, we encourage others to contribute expertise to building understanding of the sexomes of many key vertebrate species. This article is part of the theme issue 'Challenging the paradigm in sex chromosome evolution: empirical and theoretical insights with a focus on vertebrates (Part I)'.
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Affiliation(s)
- Matthias Stöck
- Leibniz-Institute of Freshwater Ecology and Inland Fisheries—IGB (Forschungsverbund Berlin), Müggelseedamm 301, 12587 Berlin, Germany
- Amphibian Research Center, Hiroshima University, Higashi-Hiroshima 739-8526, Japan
| | - Lukáš Kratochvíl
- Department of Ecology, Faculty of Science, Charles University, Viničná 7, 12844 Prague, Czech Republic
| | - Heiner Kuhl
- Leibniz-Institute of Freshwater Ecology and Inland Fisheries—IGB (Forschungsverbund Berlin), Müggelseedamm 301, 12587 Berlin, Germany
| | - Michail Rovatsos
- Amphibian Research Center, Hiroshima University, Higashi-Hiroshima 739-8526, Japan
| | - Ben J. Evans
- Department of Biology, McMaster University, Life Sciences Building Room 328, 1280 Main Street West, Hamilton, Ontario, Canada L8S 4K1
| | - Alexander Suh
- School of Biological Sciences, University of East Anglia, Norwich Research Park, Norwich NR4 7TU, UK
- Department of Organismal Biology—Systematic Biology, Evolutionary Biology Centre, Science for Life Laboratory, Uppsala University, Norbyvägen 18D, 75236 Uppsala, Sweden
| | - Nicole Valenzuela
- Department of Ecology, Evolution, and Organismal Biology, Iowa State University, Ames, IA 50011, USA
| | - Frédéric Veyrunes
- Institut des Sciences de l'Evolution de Montpellier, ISEM UMR 5554 (CNRS/Université de Montpellier/IRD/EPHE), Montpellier, France
| | - Qi Zhou
- MOE Laboratory of Biosystems Homeostasis and Protection and Zhejiang Provincial Key Laboratory for Cancer Molecular Cell Biology, Life Sciences Institute, Zhejiang University, Hangzhou, Zhejiang 310058, People's Republic of China
- Department of Neuroscience and Developmental Biology, University of Vienna, A-1090 Vienna, Austria
| | - Tony Gamble
- Department of Biological Sciences, Marquette University, Milwaukee, WI 53201, USA
| | - Blanche Capel
- Department of Cell Biology, Duke University Medical Center, Durham, NC 27710, USA
| | - Manfred Schartl
- Developmental Biochemistry, Biocenter, University of Würzburg, 97074 Würzburg, Germany
- The Xiphophorus Genetic Stock Center, Department of Chemistry and Biochemistry, Texas State University, San Marcos, TX 78666, USA
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Kostmann A, Augstenová B, Frynta D, Kratochvíl L, Rovatsos M. Cytogenetically Elusive Sex Chromosomes in Scincoidean Lizards. Int J Mol Sci 2021; 22:ijms22168670. [PMID: 34445371 PMCID: PMC8395508 DOI: 10.3390/ijms22168670] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2021] [Revised: 08/08/2021] [Accepted: 08/09/2021] [Indexed: 01/11/2023] Open
Abstract
The lizards of the species-rich clade Scincoidea including cordylids, gerrhosaurids, skinks, and xantusiids, show an almost cosmopolitan geographical distribution and a remarkable ecological and morphological divergence. However, previous studies revealed limited variability in cytogenetic traits. The sex determination mode was revealed only in a handful of gerrhosaurid, skink, and xantusiid species, which demonstrated either ZZ/ZW or XX/XY sex chromosomes. In this study, we explored the karyotypes of six species of skinks, two species of cordylids, and one gerrhosaurid. We applied conventional and molecular cytogenetic methods, including C-banding, fluorescence in situ hybridization with probes specific for telomeric motifs and rDNA loci, and comparative genomic hybridization. The diploid chromosome numbers are rather conserved among these species, but the chromosome morphology, the presence of interstitial telomeric sequences, and the topology of rDNA loci vary significantly. Notably, XX/XY sex chromosomes were identified only in Tiliqua scincoides, where, in contrast to the X chromosome, the Y chromosome lacks accumulations of rDNA loci. We confirm that within the lizards of the scincoidean clade, sex chromosomes remained in a generally poor stage of differentiation.
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Affiliation(s)
- Alexander Kostmann
- Department of Ecology, Faculty of Science, Charles University, 12844 Prague, Czech Republic; (A.K.); (B.A.); (L.K.)
| | - Barbora Augstenová
- Department of Ecology, Faculty of Science, Charles University, 12844 Prague, Czech Republic; (A.K.); (B.A.); (L.K.)
| | - Daniel Frynta
- Department of Zoology, Faculty of Science, Charles University, 12844 Prague, Czech Republic;
| | - Lukáš Kratochvíl
- Department of Ecology, Faculty of Science, Charles University, 12844 Prague, Czech Republic; (A.K.); (B.A.); (L.K.)
| | - Michail Rovatsos
- Department of Ecology, Faculty of Science, Charles University, 12844 Prague, Czech Republic; (A.K.); (B.A.); (L.K.)
- Correspondence:
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Augstenová B, Pensabene E, Veselý M, Kratochvíl L, Rovatsos M. Are Geckos Special in Sex Determination? Independently Evolved Differentiated ZZ/ZW Sex Chromosomes in Carphodactylid Geckos. Genome Biol Evol 2021; 13:evab119. [PMID: 34051083 PMCID: PMC8290109 DOI: 10.1093/gbe/evab119] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/28/2021] [Indexed: 12/20/2022] Open
Abstract
Amniotes possess astonishing variability in sex determination ranging from environmental sex determination (ESD) to genotypic sex determination (GSD) with highly differentiated sex chromosomes. Geckos are one of the few amniote groups with substantial variability in sex determination. What makes them special in this respect? We hypothesized that the extraordinary variability of sex determination in geckos can be explained by two alternatives: 1) unusual lability of sex determination, predicting that the current GSD systems were recently formed and are prone to turnovers; and 2) independent transitions from the ancestral ESD to later stable GSD, which assumes that geckos possessed ancestrally ESD, but once sex chromosomes emerged, they remain stable in the long term. Here, based on genomic data, we document that the differentiated ZZ/ZW sex chromosomes evolved within carphodactylid geckos independently from other gekkotan lineages and remained stable in the genera Nephrurus, Underwoodisaurus, and Saltuarius for at least 15 Myr and potentially up to 45 Myr. These results together with evidence for the stability of sex chromosomes in other gekkotan lineages support more our second hypothesis suggesting that geckos do not dramatically differ from the evolutionary transitions in sex determination observed in the majority of the amniote lineages.
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Affiliation(s)
- Barbora Augstenová
- Department of Ecology, Faculty of Science, Charles University, Prague, Czech Republic
| | - Eleonora Pensabene
- Department of Ecology, Faculty of Science, Charles University, Prague, Czech Republic
| | - Milan Veselý
- Department of Zoology, Faculty of Science, Palacký University, Olomouc, Czech Republic
| | - Lukáš Kratochvíl
- Department of Ecology, Faculty of Science, Charles University, Prague, Czech Republic
| | - Michail Rovatsos
- Department of Ecology, Faculty of Science, Charles University, Prague, Czech Republic
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12
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Augstenová B, Pensabene E, Kratochvíl L, Rovatsos M. Cytogenetic Evidence for Sex Chromosomes and Karyotype Evolution in Anguimorphan Lizards. Cells 2021; 10:cells10071612. [PMID: 34203198 PMCID: PMC8304200 DOI: 10.3390/cells10071612] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2021] [Revised: 06/21/2021] [Accepted: 06/22/2021] [Indexed: 12/27/2022] Open
Abstract
Anguimorphan lizards are a morphologically variable group of squamate reptiles with a wide geographical distribution. In spite of their importance, they have been cytogenetically understudied. Here, we present the results of the cytogenetic examination of 23 species from five anguimorphan families (Anguidae, Helodermatidae, Shinisauridae, Varanidae and Xenosauridae). We applied both conventional (Giemsa staining and C-banding) and molecular cytogenetic methods (fluorescence in situ hybridization with probes for the telomeric motifs and rDNA loci, comparative genome hybridization), intending to describe the karyotypes of previously unstudied species, to uncover the sex determination mode, and to reveal the distribution of variability in cytogenetic characteristics among anguimorphan lizards. We documented that karyotypes are generally quite variable across anguimorphan lineages, with anguids being the most varying. However, the derived chromosome number of 2n = 40 exhibits a notable long-term evolutionary stasis in monitors. Differentiated ZZ/ZW sex chromosomes were documented in monitors and helodermatids, as well as in the anguids Abronia lythrochila, and preliminary also in Celestus warreni and Gerrhonotus liocephalus. Several other anguimorphan species have likely poorly differentiated sex chromosomes, which cannot be detected by the applied cytogenetic methods, although the presence of environmental sex determination cannot be excluded. In addition, we uncovered a rare case of spontaneous triploidy in a fully grown Varanus primordius.
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13
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Oliveira VCS, Altmanová M, Viana PF, Ezaz T, Bertollo LAC, Ráb P, Liehr T, Al-Rikabi A, Feldberg E, Hatanaka T, Scholz S, Meurer A, de Bello Cioffi M. Revisiting the Karyotypes of Alligators and Caimans (Crocodylia, Alligatoridae) after a Half-Century Delay: Bridging the Gap in the Chromosomal Evolution of Reptiles. Cells 2021; 10:cells10061397. [PMID: 34198806 PMCID: PMC8228166 DOI: 10.3390/cells10061397] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2021] [Revised: 06/01/2021] [Accepted: 06/02/2021] [Indexed: 12/16/2022] Open
Abstract
Although crocodilians have attracted enormous attention in other research fields, from the cytogenetic point of view, this group remains understudied. Here, we analyzed the karyotypes of eight species formally described from the Alligatoridae family using differential staining, fluorescence in situ hybridization with rDNA and repetitive motifs as a probe, whole chromosome painting (WCP), and comparative genome hybridization. All Caimaninae species have a diploid chromosome number (2n) 42 and karyotypes dominated by acrocentric chromosomes, in contrast to both species of Alligatorinae, which have 2n = 32 and karyotypes that are predominantly metacentric, suggesting fusion/fission rearrangements. Our WCP results supported this scenario by revealing the homeology of the largest metacentric pair present in both Alligator spp. with two smaller pairs of acrocentrics in Caimaninae species. The clusters of 18S rDNA were found on one chromosome pair in all species, except for Paleosuchus spp., which possessed three chromosome pairs bearing these sites. Similarly, comparative genomic hybridization demonstrated an advanced stage of sequence divergence among the caiman genomes, with Paleosuchus standing out as the most divergent. Thus, although Alligatoridae exhibited rather low species diversity and some level of karyotype stasis, their genomic content indicates that they are not as conserved as previously thought. These new data deepen the discussion of cytotaxonomy in this family.
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Affiliation(s)
- Vanessa C. S. Oliveira
- Laboratório de Citogenética de Peixes, Departamento de Genética e Evolução, Universidade Federal de São Carlos, São Carlos 13565-905, Brazil; (V.C.S.O.); (L.A.C.B.); (T.H.); (M.d.B.C.)
| | - Marie Altmanová
- Department of Ecology, Faculty of Science, Charles University, 12844 Prague, Czech Republic;
- Laboratory of Fish Genetics, Institute of Animal Physiology and Genetics, Czech Academy of Sciences, 27721 Liběchov, Czech Republic;
| | - Patrik F. Viana
- Laboratório de Genética Animal, Coordenação de Biodiversidade, Instituto Nacional de Pesquisas da Amazônia, Manaus 69083-000, Brazil; (P.F.V.); (E.F.)
| | - Tariq Ezaz
- Institute for Applied Ecology, Faculty of Science and Technology, University of Canberra, Bruce, ACT 2617, Australia;
| | - Luiz A. C. Bertollo
- Laboratório de Citogenética de Peixes, Departamento de Genética e Evolução, Universidade Federal de São Carlos, São Carlos 13565-905, Brazil; (V.C.S.O.); (L.A.C.B.); (T.H.); (M.d.B.C.)
| | - Petr Ráb
- Laboratory of Fish Genetics, Institute of Animal Physiology and Genetics, Czech Academy of Sciences, 27721 Liběchov, Czech Republic;
| | - Thomas Liehr
- Institute of Human Genetics, Jena University Hospital, Am Klinikum 1, 07747 Jena, Germany;
- Correspondence: ; Tel.: +49-36-41-939-68-50; Fax: +49-3641-93-96-852
| | - Ahmed Al-Rikabi
- Institute of Human Genetics, Jena University Hospital, Am Klinikum 1, 07747 Jena, Germany;
| | - Eliana Feldberg
- Laboratório de Genética Animal, Coordenação de Biodiversidade, Instituto Nacional de Pesquisas da Amazônia, Manaus 69083-000, Brazil; (P.F.V.); (E.F.)
| | - Terumi Hatanaka
- Laboratório de Citogenética de Peixes, Departamento de Genética e Evolução, Universidade Federal de São Carlos, São Carlos 13565-905, Brazil; (V.C.S.O.); (L.A.C.B.); (T.H.); (M.d.B.C.)
| | | | | | - Marcelo de Bello Cioffi
- Laboratório de Citogenética de Peixes, Departamento de Genética e Evolução, Universidade Federal de São Carlos, São Carlos 13565-905, Brazil; (V.C.S.O.); (L.A.C.B.); (T.H.); (M.d.B.C.)
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Valenzuela N. Podocnemis expansa Turtles Hint to a Unifying Explanation for the Evolution of Temperature-Dependent Sex Determination in Long-Lived and Short-Lived Vertebrates. Sex Dev 2021; 15:23-37. [PMID: 34004596 DOI: 10.1159/000515208] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2020] [Accepted: 01/07/2021] [Indexed: 11/19/2022] Open
Abstract
The adaptive significance of temperature-dependent sex determination (TSD) remains elusive for many long-lived reptiles. Various hypotheses proposed potential ecological drivers of TSD. The Charnov-Bull'77 model remains the most robust and explains the maintenance of TSD in short-lived vertebrates, where sex ratios correlate with seasonal temperatures within years that confer sex-specific fitness (colder springs produce females who grow larger and gain in fecundity, whereas warmer summers produce males who mature at smaller size). Yet, evidence of fitness differentials correlated with incubation temperature is scarce for long-lived taxa. Here, it is proposed that the Charnov-Bull'77 model applies similarly to long-lived taxa, but at a longer temporal scale, by revisiting ecological and genetic data from the long-lived turtle Podocnemis expansa. After ruling out multiple alternatives, it is hypothesized that warmer-drier years overproduce females and correlate with optimal resource availability in the flood plains, benefitting daughters more than sons, whereas resources are scarcer (due to reduced flowering/fruiting) during colder-rainier years that overproduce males, whose fitness is less impacted by slower growth rates. New technical advances and collaborative interdisciplinary efforts are delineated that should facilitate testing this hypothesis directly, illuminating the understanding of TSD evolution in P. expansa and other long-lived TSD reptiles.
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Affiliation(s)
- Nicole Valenzuela
- Department of Ecology, Evolution, and Organismal Biology, Iowa State University, Ames, Iowa, USA
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15
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Miura I, Shams F, Lin SM, de Bello Cioffi M, Liehr T, Al-Rikabi A, Kuwana C, Srikulnath K, Higaki Y, Ezaz T. Evolution of a Multiple Sex-Chromosome System by Three-Sequential Translocations among Potential Sex-Chromosomes in the Taiwanese Frog Odorrana swinhoana. Cells 2021; 10:cells10030661. [PMID: 33809726 PMCID: PMC8002213 DOI: 10.3390/cells10030661] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2021] [Revised: 03/13/2021] [Accepted: 03/15/2021] [Indexed: 02/07/2023] Open
Abstract
Translocation between sex-chromosomes and autosomes generates multiple sex-chromosome systems. It happens unexpectedly, and therefore, the evolutionary meaning is not clear. The current study shows a multiple sex chromosome system comprising three different chromosome pairs in a Taiwanese brown frog (Odorrana swinhoana). The male-specific three translocations created a system of six sex-chromosomes, ♂X1Y1X2Y2X3Y3-♀X1X1X2X2X3X3. It is unique in that the translocations occurred among three out of the six members of potential sex-determining chromosomes, which are known to be involved in sex-chromosome turnover in frogs, and the two out of three include orthologs of the sex-determining genes in mammals, birds and fishes. This rare case suggests sex-specific, nonrandom translocations and thus provides a new viewpoint for the evolutionary meaning of the multiple sex chromosome system.
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Affiliation(s)
- Ikuo Miura
- Amphibian Research Center, Hiroshima University, 1-3-1 Kagamiyama, Higashi-Hiroshima 739-8526, Japan; (S.-M.L.); (K.S.); (T.E.)
- Center for Conservation Ecology and Genomics, University of Canberra, Canberra, ACT 2601, Australia;
- Correspondence: ; Tel.: +81-(82)-424-7323
| | - Foyez Shams
- Center for Conservation Ecology and Genomics, University of Canberra, Canberra, ACT 2601, Australia;
| | - Si-Min Lin
- Amphibian Research Center, Hiroshima University, 1-3-1 Kagamiyama, Higashi-Hiroshima 739-8526, Japan; (S.-M.L.); (K.S.); (T.E.)
- School of Life Sciences, National Taiwan Normal University, No. 88, Sec. 4, Tingzhou Road, Tapei 116, Taiwan
| | - Marcelo de Bello Cioffi
- Departamento de Genética e Evolução, Universidade Federal de São Carlos, São Carlos 13565-090, SP, Brazil;
| | - Thomas Liehr
- Institute of Human Genetics, University Hospital Jena, Am Klinikum 1, 07747 Jena, Germany; (T.L.); (A.A.-R.)
| | - Ahmed Al-Rikabi
- Institute of Human Genetics, University Hospital Jena, Am Klinikum 1, 07747 Jena, Germany; (T.L.); (A.A.-R.)
| | - Chiao Kuwana
- Graduate School of Integrated Sciences for Life, Hiroshima University, 1-4-4 Kagamiyama, Higashi-Hiroshima 739-8528, Japan; (C.K.); (Y.H.)
| | - Kornsorn Srikulnath
- Amphibian Research Center, Hiroshima University, 1-3-1 Kagamiyama, Higashi-Hiroshima 739-8526, Japan; (S.-M.L.); (K.S.); (T.E.)
- Department of Genetics, Faculty of Science, Kasetsart University, 50 Ngam Wong Wan, Lat Yao, Chatuchak, Bangkok 10900, Thailand
| | - Yuya Higaki
- Graduate School of Integrated Sciences for Life, Hiroshima University, 1-4-4 Kagamiyama, Higashi-Hiroshima 739-8528, Japan; (C.K.); (Y.H.)
| | - Tariq Ezaz
- Amphibian Research Center, Hiroshima University, 1-3-1 Kagamiyama, Higashi-Hiroshima 739-8526, Japan; (S.-M.L.); (K.S.); (T.E.)
- Center for Conservation Ecology and Genomics, University of Canberra, Canberra, ACT 2601, Australia;
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Cytogenetic Analysis of the Asian Box Turtles of the Genus Cuora (Testudines, Geoemydidae). Genes (Basel) 2021; 12:genes12020156. [PMID: 33503936 PMCID: PMC7911423 DOI: 10.3390/genes12020156] [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: 12/27/2020] [Revised: 01/18/2021] [Accepted: 01/19/2021] [Indexed: 11/18/2022] Open
Abstract
The Asian box turtle genus Cuora currently comprises 13 species with a wide distribution in Southeast Asia, including China and the islands of Indonesia and Philippines. The populations of these species are rapidly declining due to human pressure, including pollution, habitat loss, and harvesting for food consumption. Notably, the IUCN Red List identifies almost all species of the genus Cuora as Endangered (EN) or Critically Endangered (CR). In this study, we explore the karyotypes of 10 Cuora species with conventional (Giemsa staining, C-banding, karyogram reconstruction) and molecular cytogenetic methods (in situ hybridization with probes for rDNA loci and telomeric repeats). Our study reveals a diploid chromosome number of 2n = 52 chromosomes in all studied species, with karyotypes of similar chromosomal morphology. In all examined species, rDNA loci are detected at a single medium-sized chromosome pair and the telomeric repeats are restricted to the expected terminal position across all chromosomes. In contrast to a previous report, sex chromosomes are neither detected in Cuoragalbinifrons nor in any other species. Therefore, we assume that these turtles have either environmental sex determination or genotypic sex determination with poorly differentiated sex chromosomes. The conservation of genome organization could explain the numerous observed cases of interspecific hybridization both within the genus Cuora and across geoemydid turtles.
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17
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The Amazonian Red Side-Necked Turtle Rhinemys rufipes (Spix, 1824) (Testudines, Chelidae) Has a GSD Sex-Determining Mechanism with an Ancient XY Sex Microchromosome System. Cells 2020; 9:cells9092088. [PMID: 32932633 PMCID: PMC7563702 DOI: 10.3390/cells9092088] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2020] [Revised: 09/08/2020] [Accepted: 09/11/2020] [Indexed: 02/06/2023] Open
Abstract
The Amazonian red side-necked turtle Rhynemis rufipes is an endemic Amazonian Chelidae species that occurs in small streams throughout Colombia and Brazil river basins. Little is known about various biological aspects of this species, including its sex determination strategies. Among chelids, the greatest karyotype diversity is found in the Neotropical species, with several 2n configurations, including cases of triploidy. Here, we investigate the karyotype of Rhinemys rufipes by applying combined conventional and molecular cytogenetic procedures. This allowed us to discover a genetic sex-determining mechanism that shares an ancestral micro XY sex chromosome system. This ancient micro XY system recruited distinct repeat motifs before it diverged from several South America and Australasian species. We propose that such a system dates back to the earliest lineages of the chelid species before the split of South America and Australasian lineages.
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18
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Ahmad SF, Singchat W, Jehangir M, Panthum T, Srikulnath K. Consequence of Paradigm Shift with Repeat Landscapes in Reptiles: Powerful Facilitators of Chromosomal Rearrangements for Diversity and Evolution. Genes (Basel) 2020; 11:E827. [PMID: 32708239 PMCID: PMC7397244 DOI: 10.3390/genes11070827] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2020] [Revised: 07/16/2020] [Accepted: 07/17/2020] [Indexed: 12/24/2022] Open
Abstract
Reptiles are notable for the extensive genomic diversity and species richness among amniote classes, but there is nevertheless a need for detailed genome-scale studies. Although the monophyletic amniotes have recently been a focus of attention through an increasing number of genome sequencing projects, the abundant repetitive portion of the genome, termed the "repeatome", remains poorly understood across different lineages. Consisting predominantly of transposable elements or mobile and satellite sequences, these repeat elements are considered crucial in causing chromosomal rearrangements that lead to genomic diversity and evolution. Here, we propose major repeat landscapes in representative reptilian species, highlighting their evolutionary dynamics and role in mediating chromosomal rearrangements. Distinct karyotype variability, which is typically a conspicuous feature of reptile genomes, is discussed, with a particular focus on rearrangements correlated with evolutionary reorganization of micro- and macrochromosomes and sex chromosomes. The exceptional karyotype variation and extreme genomic diversity of reptiles are used to test several hypotheses concerning genomic structure, function, and evolution.
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Affiliation(s)
- Syed Farhan Ahmad
- Laboratory of Animal Cytogenetics and Comparative Genomics (ACCG), Department of Genetics, Faculty of Science, Kasetsart University, 50 Ngamwongwan, Chatuchak, Bangkok 10900, Thailand; (S.F.A.); (W.S.); (M.J.); (T.P.)
- Special Research Unit for Wildlife Genomics (SRUWG), Department of Forest Biology, Faculty of Forestry, Kasetsart University, 50 Ngamwongwan, Chatuchak, Bangkok 10900, Thailand
| | - Worapong Singchat
- Laboratory of Animal Cytogenetics and Comparative Genomics (ACCG), Department of Genetics, Faculty of Science, Kasetsart University, 50 Ngamwongwan, Chatuchak, Bangkok 10900, Thailand; (S.F.A.); (W.S.); (M.J.); (T.P.)
- Special Research Unit for Wildlife Genomics (SRUWG), Department of Forest Biology, Faculty of Forestry, Kasetsart University, 50 Ngamwongwan, Chatuchak, Bangkok 10900, Thailand
| | - Maryam Jehangir
- Laboratory of Animal Cytogenetics and Comparative Genomics (ACCG), Department of Genetics, Faculty of Science, Kasetsart University, 50 Ngamwongwan, Chatuchak, Bangkok 10900, Thailand; (S.F.A.); (W.S.); (M.J.); (T.P.)
- Integrative Genomics Lab-LGI, Department of Structural and Functional Biology, Institute of Bioscience at Botucatu, São Paulo State University (UNESP), Botucatu 18618-689, Brazil
| | - Thitipong Panthum
- Laboratory of Animal Cytogenetics and Comparative Genomics (ACCG), Department of Genetics, Faculty of Science, Kasetsart University, 50 Ngamwongwan, Chatuchak, Bangkok 10900, Thailand; (S.F.A.); (W.S.); (M.J.); (T.P.)
- Special Research Unit for Wildlife Genomics (SRUWG), Department of Forest Biology, Faculty of Forestry, Kasetsart University, 50 Ngamwongwan, Chatuchak, Bangkok 10900, Thailand
| | - Kornsorn Srikulnath
- Laboratory of Animal Cytogenetics and Comparative Genomics (ACCG), Department of Genetics, Faculty of Science, Kasetsart University, 50 Ngamwongwan, Chatuchak, Bangkok 10900, Thailand; (S.F.A.); (W.S.); (M.J.); (T.P.)
- Special Research Unit for Wildlife Genomics (SRUWG), Department of Forest Biology, Faculty of Forestry, Kasetsart University, 50 Ngamwongwan, Chatuchak, Bangkok 10900, Thailand
- Center for Advanced Studies in Tropical Natural Resources, National Research University-Kasetsart University, Kasetsart University, Bangkok 10900, Thailand
- Center of Excellence on Agricultural Biotechnology (AG-BIO/PERDO-CHE), Bangkok 10900, Thailand
- Omics Center for Agriculture, Bioresources, Food and Health, Kasetsart University (OmiKU), Bangkok 10900, Thailand
- Amphibian Research Center, Hiroshima University, 1-3-1, Kagamiyama, Higashihiroshima 739-8526, Japan
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19
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Molecular Cytogenetic Characterization of the Sicilian Endemic Pond Turtle Emys trinacris and the Yellow-Bellied Slider Trachemys scripta scripta (Testudines, Emydidae). Genes (Basel) 2020; 11:genes11060702. [PMID: 32630506 PMCID: PMC7348936 DOI: 10.3390/genes11060702] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2020] [Revised: 06/23/2020] [Accepted: 06/23/2020] [Indexed: 01/15/2023] Open
Abstract
Turtles, a speciose group consisting of more than 300 species, demonstrate karyotypes with diploid chromosome numbers ranging from 2n = 26 to 2n = 68. However, cytogenetic analyses have been conducted only to 1/3rd of the turtle species, often limited to conventional staining methods. In order to expand our knowledge of the karyotype evolution in turtles, we examined the topology of the (TTAGGG)n telomeric repeats and the rDNA loci by fluorescence in situ hybridization (FISH) on the karyotypes of two emydids: the Sicilian pond turtle, Emys trinacris, and the yellow-bellied slider, Trachemys scripta scripta (family Emydidae). Furthermore, AT-rich and GC-rich chromosome regions were detected by DAPI and CMA3 stains, respectively. The cytogenetic analysis revealed that telomeric sequences are restricted to the terminal ends of all chromosomes and the rDNA loci are localized in one pair of microchromosomes in both species. The karyotype of the Sicilian endemic E. trinacris with diploid number 2n = 50, consisting of 13 pairs of macrochromosomes and 12 pairs of microchromosomes, is presented here for first time. Our comparative examination revealed similar cytogenetic features in Emys trinacris and the closely related E. orbicularis, as well as to other previously studied emydid species, demonstrating a low rate of karyotype evolution, as chromosomal rearrangements are rather infrequent in this group of turtles.
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20
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Clemente L, Mazzoleni S, Pensabene Bellavia E, Augstenová B, Auer M, Praschag P, Protiva T, Velenský P, Wagner P, Fritz U, Kratochvíl L, Rovatsos M. Interstitial Telomeric Repeats Are Rare in Turtles. Genes (Basel) 2020; 11:genes11060657. [PMID: 32560114 PMCID: PMC7348932 DOI: 10.3390/genes11060657] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2020] [Revised: 06/09/2020] [Accepted: 06/10/2020] [Indexed: 01/18/2023] Open
Abstract
Telomeres are nucleoprotein complexes protecting chromosome ends in most eukaryotic organisms. In addition to chromosome ends, telomeric-like motifs can be accumulated in centromeric, pericentromeric and intermediate (i.e., between centromeres and telomeres) positions as so-called interstitial telomeric repeats (ITRs). We mapped the distribution of (TTAGGG)n repeats in the karyotypes of 30 species from nine families of turtles using fluorescence in situ hybridization. All examined species showed the expected terminal topology of telomeric motifs at the edges of chromosomes. We detected ITRs in only five species from three families. Combining our and literature data, we inferred seven independent origins of ITRs among turtles. ITRs occurred in turtles in centromeric positions, often in several chromosomal pairs, in a given species. Their distribution does not correspond directly to interchromosomal rearrangements. Our findings support that centromeres and non-recombining parts of sex chromosomes are very dynamic genomic regions, even in turtles, a group generally thought to be slowly evolving. However, in contrast to squamate reptiles (lizards and snakes), where ITRs were found in more than half of the examined species, and birds, the presence of ITRs is generally rare in turtles, which agrees with the expected low rates of chromosomal rearrangements and rather slow karyotype evolution in this group.
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Affiliation(s)
- Lorenzo Clemente
- Department of Ecology, Faculty of Science, Charles University, 12844 Prague, Czech Republic; (L.C.); (S.M.); (E.P.B.); (B.A.); (L.K.)
| | - Sofia Mazzoleni
- Department of Ecology, Faculty of Science, Charles University, 12844 Prague, Czech Republic; (L.C.); (S.M.); (E.P.B.); (B.A.); (L.K.)
| | - Eleonora Pensabene Bellavia
- Department of Ecology, Faculty of Science, Charles University, 12844 Prague, Czech Republic; (L.C.); (S.M.); (E.P.B.); (B.A.); (L.K.)
| | - Barbora Augstenová
- Department of Ecology, Faculty of Science, Charles University, 12844 Prague, Czech Republic; (L.C.); (S.M.); (E.P.B.); (B.A.); (L.K.)
| | - Markus Auer
- Museum of Zoology, Senckenberg Dresden, 01109 Dresden, Germany; (M.A.); (U.F.)
| | | | | | - Petr Velenský
- Prague Zoological Garden, 17100 Prague, Czech Republic;
| | | | - Uwe Fritz
- Museum of Zoology, Senckenberg Dresden, 01109 Dresden, Germany; (M.A.); (U.F.)
| | - Lukáš Kratochvíl
- Department of Ecology, Faculty of Science, Charles University, 12844 Prague, Czech Republic; (L.C.); (S.M.); (E.P.B.); (B.A.); (L.K.)
| | - Michail Rovatsos
- Department of Ecology, Faculty of Science, Charles University, 12844 Prague, Czech Republic; (L.C.); (S.M.); (E.P.B.); (B.A.); (L.K.)
- Correspondence:
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21
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Turtle Insights into the Evolution of the Reptilian Karyotype and the Genomic Architecture of Sex Determination. Genes (Basel) 2020; 11:genes11040416. [PMID: 32290488 PMCID: PMC7231036 DOI: 10.3390/genes11040416] [Citation(s) in RCA: 33] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2020] [Revised: 04/06/2020] [Accepted: 04/08/2020] [Indexed: 01/01/2023] Open
Abstract
Sex chromosome evolution remains an evolutionary puzzle despite its importance in understanding sexual development and genome evolution. The seemingly random distribution of sex-determining systems in reptiles offers a unique opportunity to study sex chromosome evolution not afforded by mammals or birds. These reptilian systems derive from multiple transitions in sex determination, some independent, some convergent, that lead to the birth and death of sex chromosomes in various lineages. Here we focus on turtles, an emerging model group with growing genomic resources. We review karyotypic changes that accompanied the evolution of chromosomal systems of genotypic sex determination (GSD) in chelonians from systems under the control of environmental temperature (TSD). These transitions gave rise to 31 GSD species identified thus far (out of 101 turtles with known sex determination), 27 with a characterized sex chromosome system (13 of those karyotypically). These sex chromosomes are varied in terms of the ancestral autosome they co-opted and thus in their homology, as well as in their size (some are macro-, some are micro-chromosomes), heterogamety (some are XX/XY, some ZZ/ZW), dimorphism (some are virtually homomorphic, some heteromorphic with larger-X, larger W, or smaller-Y), age (the oldest system could be ~195 My old and the youngest < 25 My old). Combined, all data indicate that turtles follow some tenets of classic theoretical models of sex chromosome evolution while countering others. Finally, although the study of dosage compensation and molecular divergence of turtle sex chromosomes has lagged behind research on other aspects of their evolution, this gap is rapidly decreasing with the acceleration of ongoing research and growing genomic resources in this group.
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