1
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Pensabene E, Augstenová B, Kratochvíl L, Rovatsos M. Differentiated sex chromosomes, karyotype evolution, and spontaneous triploidy in carphodactylid geckos. J Hered 2024; 115:262-276. [PMID: 38366660 DOI: 10.1093/jhered/esae010] [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: 11/02/2023] [Accepted: 02/13/2024] [Indexed: 02/18/2024] Open
Abstract
Geckos exhibit derived karyotypes without a clear distinction between macrochromosomes and microchromosomes and intriguing diversity in sex determination mechanisms. We conducted cytogenetic analyses in six species from the genera Nephrurus, Phyllurus, and Saltuarius of the gecko family Carphodactylidae. We confirmed the presence of a female heterogametic system with markedly differentiated and heteromorphic sex chromosomes in all examined species, typically with the W chromosome notably larger than the Z chromosome. One species, Nephrurus cinctus, possesses unusual multiple Z1Z1Z2Z2/Z1Z2W sex chromosomes. The morphology of the sex chromosomes, along with repetitive DNA content, suggests that the differentiation or emergence of sex chromosomes occurred independently in the genus Phyllurus. Furthermore, our study unveils a case of spontaneous triploidy in a fully grown individual of Saltuarius cornutus (3n = 57) and explores its implications for reproduction in carphodactylid geckos. We revealed that most carphodactylids retain the putative ancestral gekkotan karyotype of 2n = 38, characterized by predominantly acrocentric chromosomes that gradually decrease in size. If present, biarmed chromosomes emerge through pericentric inversions, maintaining the chromosome (and centromere) numbers. However, Phyllurus platurus is a notable exception, with a karyotype of 2n = 22 chromosomes. Its eight pairs of biarmed chromosomes were probably formed by Robertsonian fusions of acrocentric chromosomes. The family underscores a remarkable instance of evolutionary stability in chromosome numbers, followed by a profound transformation through parallel interchromosomal rearrangements. Our study highlights the need to continue generating cytogenetic data in order to test long-standing ideas about reproductive biology and the evolution of genome and sex determination.
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Affiliation(s)
- Eleonora Pensabene
- Department of Ecology, Faculty of Science, Charles University, Prague, Czech Republic
| | - Barbora Augstenová
- Department of Ecology, Faculty of Science, Charles University, Prague, 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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2
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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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3
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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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4
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Keating SE, Greenbaum E, Johnson JD, Gamble T. Identification of a cis-sex chromosome transition in banded geckos (Coleonyx, Eublepharidae, Gekkota). J Evol Biol 2022; 35:1675-1682. [PMID: 35665979 DOI: 10.1111/jeb.14022] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2022] [Revised: 04/13/2022] [Accepted: 04/28/2022] [Indexed: 12/24/2022]
Abstract
Sex-determination systems are highly variable amongst vertebrate groups, and the prevalence of genomic data has greatly expanded our knowledge of how diverse some groups truly are. Gecko lizards are known to possess a variety of sex-determination systems, and each new study increases our knowledge of this diversity. Here, we used RADseq to identify male-specific markers in the banded gecko Coleonyx brevis, indicating this species has a XX/XY sex-determination system. Furthermore, we show that these sex-linked regions are not homologous to the XX/XY sex chromosomes of two related Coleonyx species, C. elegans and C. mitratus, suggesting that a cis-sex chromosome turnover-a change in sex chromosomes without a concomitant change in heterogamety-has occurred within the genus. These findings demonstrate the utility of genome-scale data to uncover novel sex chromosomes and further highlight the diversity of gecko sex chromosomes.
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Affiliation(s)
- Shannon E Keating
- Department of Biological Sciences, Marquette University, Milwaukee, Wisconsin, USA
| | - Eli Greenbaum
- Department of Biological Sciences, University of Texas at El Paso, El Paso, Texas, USA
| | - Jerry D Johnson
- Department of Biological Sciences, University of Texas at El Paso, El Paso, Texas, USA
| | - Tony Gamble
- Department of Biological Sciences, Marquette University, Milwaukee, Wisconsin, USA.,Milwaukee Public Museum, Milwaukee, Wisconsin, USA.,Bell Museum of Natural History, University of Minnesota, St. Paul, Minnesota, USA
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5
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Poignet M, Johnson Pokorná M, Altmanová M, Majtánová Z, Dedukh D, Albrecht T, Reif J, Osiejuk TS, Reifová R. Comparison of Karyotypes in Two Hybridizing Passerine Species: Conserved Chromosomal Structure but Divergence in Centromeric Repeats. Front Genet 2021; 12:768987. [PMID: 34938317 PMCID: PMC8687609 DOI: 10.3389/fgene.2021.768987] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2021] [Accepted: 11/10/2021] [Indexed: 11/23/2022] Open
Abstract
Changes in chromosomal structure involving chromosomal rearrangements or copy number variation of specific sequences can play an important role in speciation. Here, we explored the chromosomal structure of two hybridizing passerine species; the common nightingale (Luscinia megarhynchos) and the thrush nightingale (Luscinia luscinia), using conventional cytogenetic approaches, immunostaining of meiotic chromosomes, fluorescence in situ hybridization as well as comparative genomic hybridization (CGH). We found that the two nightingale species show conserved karyotypes with the same diploid chromosome number of 2n = 84. In addition to standard chromosomes, both species possessed a small germline restricted chromosome of similar size as a microchromosome. Just a few subtle changes in chromosome morphology were observed between the species, suggesting that only a limited number of chromosomal rearrangements occurred after the species divergence. The interspecific CGH experiment suggested that the two nightingale species might have diverged in centromeric repetitive sequences in most macro- and microchromosomes. In addition, some chromosomes showed changes in copy number of centromeric repeats between the species. The observation of very similar karyotypes in the two nightingale species is consistent with a generally slow rate of karyotype evolution in birds. The divergence of centromeric sequences between the two species could theoretically cause meiotic drive or reduced fertility in interspecific hybrids. Nevertheless, further studies are needed to evaluate the potential role of chromosomal structural variations in nightingale speciation.
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Affiliation(s)
- Manon Poignet
- Department of Zoology, Faculty of Science, Charles University, Prague, Czech Republic
| | - Martina Johnson Pokorná
- Department of Zoology, Faculty of Science, Charles University, Prague, Czech Republic
- Department of Ecology, Faculty of Science, Charles University, Prague, Czech Republic
- Institute of Animal Physiology and Genetics, Czech Academy of Sciences, Liběchov, Czech Republic
| | - Marie Altmanová
- Department of Ecology, Faculty of Science, Charles University, Prague, Czech Republic
- Institute of Animal Physiology and Genetics, Czech Academy of Sciences, Liběchov, Czech Republic
| | - Zuzana Majtánová
- Institute of Animal Physiology and Genetics, Czech Academy of Sciences, Liběchov, Czech Republic
| | - Dmitry Dedukh
- Institute of Animal Physiology and Genetics, Czech Academy of Sciences, Liběchov, Czech Republic
| | - Tomáš Albrecht
- Department of Zoology, Faculty of Science, Charles University, Prague, Czech Republic
- Institute of Vertebrate Biology, Czech Academy of Sciences, Brno, Czech Republic
| | - Jiří Reif
- Institute for Environmental Studies, Faculty of Science, Charles University, Prague, Czech Republic
- Department of Zoology and Laboratory of Ornithology, Faculty of Science, Palacký University, Olomouc, Czech Republic
| | - Tomasz S. Osiejuk
- Department of Behavioural Ecology, Institute of Environmental Biology, Faculty of Biology, Adam Mickiewicz University, Poznań, Poland
| | - Radka Reifová
- Department of Zoology, Faculty of Science, Charles University, Prague, Czech Republic
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6
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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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7
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Kratochvíl L, Gamble T, Rovatsos M. Sex chromosome evolution among amniotes: is the origin of sex chromosomes non-random? Philos Trans R Soc Lond B Biol Sci 2021; 376:20200108. [PMID: 34304592 PMCID: PMC8310715 DOI: 10.1098/rstb.2020.0108] [Citation(s) in RCA: 24] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 01/14/2021] [Indexed: 12/29/2022] Open
Abstract
Sex chromosomes are a great example of a convergent evolution at the genomic level, having evolved dozens of times just within amniotes. An intriguing question is whether this repeated evolution was random, or whether some ancestral syntenic blocks have significantly higher chance to be co-opted for the role of sex chromosomes owing to their gene content related to gonad development. Here, we summarize current knowledge on the evolutionary history of sex determination and sex chromosomes in amniotes and evaluate the hypothesis of non-random emergence of sex chromosomes. The current data on the origin of sex chromosomes in amniotes suggest that their evolution is indeed non-random. However, this non-random pattern is not very strong, and many syntenic blocks representing putatively independently evolved sex chromosomes are unique. Still, repeatedly co-opted chromosomes are an excellent model system, as independent co-option of the same genomic region for the role of sex chromosome offers a great opportunity for testing evolutionary scenarios on the sex chromosome evolution under the explicit control for the genomic background and gene identity. Future studies should use these systems more to explore the convergent/divergent evolution of sex chromosomes. This article is part of the theme issue 'Challenging the paradigm in sex chromosome evolution: empirical and theoretical insights with a focus on vertebrates (Part II)'.
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Affiliation(s)
- Lukáš Kratochvíl
- Department of Ecology, Faculty of Science, Charles University, Viničná 7, Prague, Czech Republic
| | - Tony Gamble
- Department of Biological Sciences, Marquette University, Milwaukee, WI, USA
- Bell Museum of Natural History, University of Minnesota, Saint Paul, MN, USA
- Milwaukee Public Museum, Milwaukee, WI, USA
| | - Michail Rovatsos
- Department of Ecology, Faculty of Science, Charles University, Viničná 7, Prague, Czech Republic
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8
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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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9
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Ehl J, Altmanová M, Kratochvíl L. With or Without W? Molecular and Cytogenetic Markers are Not Sufficient for Identification of Environmentally-Induced Sex Reversal in the Bearded Dragon. Sex Dev 2021; 15:272-281. [PMID: 33756476 DOI: 10.1159/000514195] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2020] [Accepted: 12/22/2020] [Indexed: 12/24/2022] Open
Abstract
Transitions from environmental sex determination (ESD) to genotypic sex determination (GSD) require an intermediate step of sex reversal, i.e., the production of individuals with a mismatch between the ancestral genotypic and the phenotypic sex. Among amniotes, the sole well-documented transition in this direction was shown in the laboratory in the central bearded dragon, Pogona vitticeps, where very high incubation temperatures led to the production of females with the male-typical (ZZ) genotype. These sex-reversed females then produced offspring whose sex depended on the incubation temperature. Sex-reversed animals identified by molecular and cytogenetic markers were also reported in the field, and their increasing incidence was speculated as a climate warming-driven transition in sex determination. We show that the molecular and cytogenetic markers normally sex-linked in P. vitticeps are also sex-linked in P. henrylawsoni and P. minor, which points to quite ancient sex chromosomes in this lineage. Nevertheless, we demonstrate, based on a crossing experiment with a male bearded dragon who possesses a mismatch between phenotypic sex and genotype, that the used cytogenetic and molecular markers might not be reliable for the identification of sex reversal. Sex reversal should not be considered as the only mechanism causing a mismatch between genetic sex-linked markers and phenotypic sex, which can emerge also by other processes, here most likely by a rare recombination between regions of sex chromosomes which are normally sex-linked. We warn that sex-linked, even apparently for a long evolutionary time, and sex-specific molecular and cytogenetic markers are not a reliable tool for the identification of sex-reversed individuals in a population and that sex reversal has to be verified by other approaches, particularly by observation of the sex ratio of the progeny.
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Affiliation(s)
- Jan Ehl
- Department of Ecology, Faculty of Science, Charles University, Prague, Czechia
| | - Marie Altmanová
- Department of Ecology, Faculty of Science, Charles University, Prague, Czechia.,Institute of Animal Physiology and Genetics, The Czech Academy of Sciences, Liběchov, Czechia
| | - Lukáš Kratochvíl
- Department of Ecology, Faculty of Science, Charles University, Prague, Czechia,
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10
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Kostmann A, Kratochvíl L, Rovatsos M. Poorly differentiated XX/XY sex chromosomes are widely shared across skink radiation. Proc Biol Sci 2021; 288:20202139. [PMID: 33468012 PMCID: PMC7893288 DOI: 10.1098/rspb.2020.2139] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2020] [Accepted: 12/23/2020] [Indexed: 11/12/2022] Open
Abstract
Differentiated sex chromosomes are believed to be evolutionarily stable, while poorly differentiated sex chromosomes are considered to be prone to turnovers. With around 1700 currently known species forming ca 15% of reptile species diversity, skinks (family Scincidae) are a very diverse group of squamates known for their large ecological and morphological variability. Skinks generally have poorly differentiated and cytogenetically indistinguishable sex chromosomes, and their sex determination was suggested to be highly variable. Here, we determined X-linked genes in the common sandfish (Scincus scincus) and demonstrate that skinks have shared the same homologous XX/XY sex chromosomes across their wide phylogenetic spectrum for at least 85 million years, approaching the age of the highly differentiated ZZ/ZW sex chromosomes of birds and advanced snakes. Skinks thus demonstrate that even poorly differentiated sex chromosomes can be evolutionarily stable. The conservation of sex chromosomes across skinks allows us to introduce the first molecular sexing method widely applicable in this group.
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Affiliation(s)
| | | | - Michail Rovatsos
- Department of Ecology, Faculty of Science, Charles University, Prague, Czech Republic
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11
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Pensabene E, Kratochvíl L, Rovatsos M. Independent Evolution of Sex Chromosomes in Eublepharid Geckos, A Lineage with Environmental and Genotypic Sex Determination. Life (Basel) 2020; 10:E342. [PMID: 33322017 PMCID: PMC7763811 DOI: 10.3390/life10120342] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2020] [Revised: 12/04/2020] [Accepted: 12/07/2020] [Indexed: 12/28/2022] Open
Abstract
Geckos demonstrate a remarkable variability in sex determination systems, but our limited knowledge prohibits accurate conclusions on the evolution of sex determination in this group. Eyelid geckos (Eublepharidae) are of particular interest, as they encompass species with both environmental and genotypic sex determination. We identified for the first time the X-specific gene content in the Yucatán banded gecko, Coleonyx elegans, possessing X1X1X2X2/X1X2Y multiple sex chromosomes by comparative genome coverage analysis between sexes. The X-specific gene content of Coleonyx elegans was revealed to be partially homologous to genomic regions linked to the chicken autosomes 1, 6 and 11. A qPCR-based test was applied to validate a subset of X-specific genes by comparing the difference in gene copy numbers between sexes, and to explore the homology of sex chromosomes across eleven eublepharid, two phyllodactylid and one sphaerodactylid species. Homologous sex chromosomes are shared between Coleonyx elegans and Coleonyx mitratus, two species diverged approximately 34 million years ago, but not with other tested species. As far as we know, the X-specific gene content of Coleonyx elegans / Coleonyx mitratus was never involved in the sex chromosomes of other gecko lineages, indicating that the sex chromosomes in this clade of eublepharid geckos evolved independently.
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Affiliation(s)
| | | | - Michail Rovatsos
- Department of Ecology, Faculty of Science, Charles University, 12844 Prague, Czech Republic; (E.P.); (L.K.)
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12
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Cubides-Cubillos SD, Patané JSL, Pereira da Silva KM, Almeida-Santos SM, Polydoro DS, Galassi GG, Travaglia Cardoso SR, Silva MJDJ. Evidence of facultative parthenogenesis in three Neotropical pitviper species of the Bothrops atrox group. PeerJ 2020; 8:e10097. [PMID: 33240594 PMCID: PMC7680053 DOI: 10.7717/peerj.10097] [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: 10/15/2019] [Accepted: 09/14/2020] [Indexed: 11/20/2022] Open
Abstract
We examined four suspected cases of facultative parthenogenesis in three species of a neotropical lineage of pitvipers of the Bothrops atrox group. Reproduction without mating was observed in captive females of B. atrox, B. moojeni and B. leucurus housed alone for seven years (the two former species) and nine years (the latter one). In addition to the observation of captivity data, we investigated molecularly this phenomenon using heterologous microsatellites. DNA was extracted from the mothers’ scales or liver, from embryo and newborn fragments, and yolked ova. Four of the microsatellites showed good amplification using Polymerase Chain Reaction and informative band segregation patterns among each mother and respective offspring. Captivity information, litter characteristics (comparison of the number of newborns, embryos and yolked ova) and molecular data altogether agreed with facultative parthenogenesis predictions in at least three out of the four mothers studied: B. atrox (ID#933) was heterozygous for three out of the four markers, and the sons S1 and S2 were homozygous; B. moojeni (BUT86) was heterozygous for two out of four markers, offspring S1, S3, E2, and E4, and O1 to O6 were homozygous; and B. leucurus (MJJS503) was heterozygous for three out of four markers, and son E1 and O1 were homozygous. B. moojeni (BUT44) was homozygous for all loci analyzed in the mother and offspring, which although not informative is also consistent with parthenogenesis. This study represents the first molecular confirmation of different pitviper species undergoing facultative parthenogenesis among Neotropical endemic snakes.
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Affiliation(s)
| | - José S L Patané
- Laboratório de Ecologia e Evolução, Instituto Butantan, São Paulo, Brazil.,Laboratório Especial de Ciclo Celular, Instituto Butantan, São Paulo, Brazil
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13
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Kratochvíl L, Vukić J, Červenka J, Kubička L, Johnson Pokorná M, Kukačková D, Rovatsos M, Piálek L. Mixed-sex offspring produced via cryptic parthenogenesis in a lizard. Mol Ecol 2020; 29:4118-4127. [PMID: 32881125 DOI: 10.1111/mec.15617] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2019] [Revised: 07/30/2020] [Accepted: 08/17/2020] [Indexed: 11/30/2022]
Abstract
Facultative parthenogenesis in vertebrates is believed to be exceptional, and wherever documented, it always led to single-sex progeny with genome-wide homozygosity. We report the first challenge to this paradigm: frequent facultative parthenogenesis in the previously assumed sexually reproducing tropical night lizard Lepidophyma smithii results in offspring of both sexes and preserves heterozygosity in many loci polymorphic in their mothers. Moreover, we documented a mixture of sexually and parthenogenetically produced progeny in a single clutch, which documents how cryptic a facultative parthenogenesis can be. Next, we show that in the studied species, 1) parthenogenetically produced females can further reproduce parthenogenetically, 2) a sexually produced female can reproduce parthenogenetically, 3) a parthenogenetically produced female can reproduce sexually, and 4) a parthenogenetically produced male is fully fertile. We suggest that facultative parthenogenesis should be considered even in vertebrates with frequent males and genetically variable, heterozygous offspring.
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Affiliation(s)
- Lukáš Kratochvíl
- Department of Ecology, Faculty of Science, Charles University, Prague, Czech Republic
| | - Jasna Vukić
- Department of Ecology, Faculty of Science, Charles University, Prague, Czech Republic
| | - Jan Červenka
- Department of Ecology, Faculty of Science, Charles University, Prague, Czech Republic
| | - Lukáš Kubička
- Department of Ecology, Faculty of Science, Charles University, Prague, Czech Republic
| | - Martina Johnson Pokorná
- Department of Ecology, Faculty of Science, Charles University, Prague, Czech Republic.,Institute of Animal Physiology and Genetics, The Czech Academy of Sciences, Liběchov, Czech Republic
| | - Dominika Kukačková
- Department of Ecology, Faculty of Science, Charles University, Prague, Czech Republic
| | - Michail Rovatsos
- Department of Ecology, Faculty of Science, Charles University, Prague, Czech Republic
| | - Lubomír Piálek
- Department of Ecology, Faculty of Science, Charles University, Prague, Czech Republic.,Department of Zoology, Faculty of Science, University of South Bohemia, České Budějovice, Czech Republic
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14
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Sember A, Pappová M, Forman M, Nguyen P, Marec F, Dalíková M, Divišová K, Doležálková-Kaštánková M, Zrzavá M, Sadílek D, Hrubá B, Král J. Patterns of Sex Chromosome Differentiation in Spiders: Insights from Comparative Genomic Hybridisation. Genes (Basel) 2020; 11:E849. [PMID: 32722348 PMCID: PMC7466014 DOI: 10.3390/genes11080849] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2020] [Revised: 07/21/2020] [Accepted: 07/21/2020] [Indexed: 01/21/2023] Open
Abstract
Spiders are an intriguing model to analyse sex chromosome evolution because of their peculiar multiple X chromosome systems. Y chromosomes were considered rare in this group, arising after neo-sex chromosome formation by X chromosome-autosome rearrangements. However, recent findings suggest that Y chromosomes are more common in spiders than previously thought. Besides neo-sex chromosomes, they are also involved in the ancient X1X2Y system of haplogyne spiders, whose origin is unknown. Furthermore, spiders seem to exhibit obligatorily one or two pairs of cryptic homomorphic XY chromosomes (further cryptic sex chromosome pairs, CSCPs), which could represent the ancestral spider sex chromosomes. Here, we analyse the molecular differentiation of particular types of spider Y chromosomes in a representative set of ten species by comparative genomic hybridisation (CGH). We found a high Y chromosome differentiation in haplogyne species with X1X2Y system except for Loxosceles spp. CSCP chromosomes exhibited generally low differentiation. Possible mechanisms and factors behind the observed patterns are discussed. The presence of autosomal regions marked predominantly or exclusively with the male or female probe was also recorded. We attribute this pattern to intraspecific variability in the copy number and distribution of certain repetitive DNAs in spider genomes, pointing thus to the limits of CGH in this arachnid group. In addition, we confirmed nonrandom association of chromosomes belonging to particular CSCPs at spermatogonial mitosis and spermatocyte meiosis and their association with multiple Xs throughout meiosis. Taken together, our data suggest diverse evolutionary pathways of molecular differentiation in different types of spider Y chromosomes.
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Affiliation(s)
- Alexandr Sember
- Laboratory of Fish Genetics, Institute of Animal Physiology and Genetics, Czech Academy of Sciences, Rumburská 89, 277 21 Liběchov, Czech Republic;
- Laboratory of Arachnid Cytogenetics, Department of Genetics and Microbiology, Faculty of Science, Charles University, Viničná 5, 128 44 Prague, Czech Republic; (M.P.); (M.F.); (K.D.); (D.S.); (B.H.); (J.K.)
| | - Michaela Pappová
- Laboratory of Arachnid Cytogenetics, Department of Genetics and Microbiology, Faculty of Science, Charles University, Viničná 5, 128 44 Prague, Czech Republic; (M.P.); (M.F.); (K.D.); (D.S.); (B.H.); (J.K.)
| | - Martin Forman
- Laboratory of Arachnid Cytogenetics, Department of Genetics and Microbiology, Faculty of Science, Charles University, Viničná 5, 128 44 Prague, Czech Republic; (M.P.); (M.F.); (K.D.); (D.S.); (B.H.); (J.K.)
| | - Petr Nguyen
- Department of Molecular Biology and Genetics, Faculty of Science, University of South Bohemia, Branišovská 1760, 370 05 České Budějovice, Czech Republic; (P.N.); (M.D.); (M.Z.)
- Biology Centre of the Czech Academy of Sciences, Institute of Entomology, Branišovská 31, 370 05 České Budějovice, Czech Republic;
| | - František Marec
- Biology Centre of the Czech Academy of Sciences, Institute of Entomology, Branišovská 31, 370 05 České Budějovice, Czech Republic;
| | - Martina Dalíková
- Department of Molecular Biology and Genetics, Faculty of Science, University of South Bohemia, Branišovská 1760, 370 05 České Budějovice, Czech Republic; (P.N.); (M.D.); (M.Z.)
- Biology Centre of the Czech Academy of Sciences, Institute of Entomology, Branišovská 31, 370 05 České Budějovice, Czech Republic;
| | - Klára Divišová
- Laboratory of Arachnid Cytogenetics, Department of Genetics and Microbiology, Faculty of Science, Charles University, Viničná 5, 128 44 Prague, Czech Republic; (M.P.); (M.F.); (K.D.); (D.S.); (B.H.); (J.K.)
| | - Marie Doležálková-Kaštánková
- Laboratory of Fish Genetics, Institute of Animal Physiology and Genetics, Czech Academy of Sciences, Rumburská 89, 277 21 Liběchov, Czech Republic;
- Laboratory of Arachnid Cytogenetics, Department of Genetics and Microbiology, Faculty of Science, Charles University, Viničná 5, 128 44 Prague, Czech Republic; (M.P.); (M.F.); (K.D.); (D.S.); (B.H.); (J.K.)
| | - Magda Zrzavá
- Department of Molecular Biology and Genetics, Faculty of Science, University of South Bohemia, Branišovská 1760, 370 05 České Budějovice, Czech Republic; (P.N.); (M.D.); (M.Z.)
- Biology Centre of the Czech Academy of Sciences, Institute of Entomology, Branišovská 31, 370 05 České Budějovice, Czech Republic;
| | - David Sadílek
- Laboratory of Arachnid Cytogenetics, Department of Genetics and Microbiology, Faculty of Science, Charles University, Viničná 5, 128 44 Prague, Czech Republic; (M.P.); (M.F.); (K.D.); (D.S.); (B.H.); (J.K.)
- Department of Zoology, Faculty of Science, Charles University, Viničná 7, 128 44 Prague, Czech Republic
| | - Barbora Hrubá
- Laboratory of Arachnid Cytogenetics, Department of Genetics and Microbiology, Faculty of Science, Charles University, Viničná 5, 128 44 Prague, Czech Republic; (M.P.); (M.F.); (K.D.); (D.S.); (B.H.); (J.K.)
| | - Jiří Král
- Laboratory of Arachnid Cytogenetics, Department of Genetics and Microbiology, Faculty of Science, Charles University, Viničná 5, 128 44 Prague, Czech Republic; (M.P.); (M.F.); (K.D.); (D.S.); (B.H.); (J.K.)
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15
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Majtánová Z, Unmack PJ, Prasongmaneerut T, Shams F, Srikulnath K, Ráb P, Ezaz T. Evidence of Interspecific Chromosomal Diversification in Rainbowfishes (Melanotaeniidae, Teleostei). Genes (Basel) 2020; 11:E818. [PMID: 32708365 PMCID: PMC7397213 DOI: 10.3390/genes11070818] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2020] [Revised: 07/13/2020] [Accepted: 07/15/2020] [Indexed: 11/28/2022] Open
Abstract
Rainbowfishes (Melanotaeniidae) are the largest monophyletic group of freshwater fishes occurring in Australia and New Guinea, with 112 species currently recognised. Despite their high taxonomic diversity, rainbowfishes remain poorly studied from a cytogenetic perspective. Using conventional (Giemsa staining, C banding, chromomycin A3 staining) and molecular (fluorescence in situ hybridisation with ribosomal DNA (rDNA) and telomeric probes) cytogenetic protocols, karyotypes and associated chromosomal characteristics of five species were examined. We covered all major lineages of this group, namely, Running River rainbowfish Melanotaenia sp., red rainbowfish Glossolepisincisus, threadfin rainbowfish Iriatherina werneri, ornate rainbowfish Rhadinocentrus ornatus, and Cairns rainbowfish Cairnsichthys rhombosomoides. All species had conserved diploid chromosome numbers 2n = 48, but karyotypes differed among species; while Melanotaenia sp., G. incisus, and I. werneri possessed karyotypes composed of exclusively subtelo/acrocentric chromosomes, the karyotype of R. ornatus displayed six pairs of submetacentric and 18 pairs of subtelo/acrocentric chromosomes, while C. rhombosomoides possessed a karyotype composed of four pairs of submetacentric and 20 pairs of subtelo/acrocentric chromosomes. No heteromorphic sex chromosomes were detected using conventional cytogenetic techniques. Our data indicate a conserved 2n in Melanotaeniidae, but morphologically variable karyotypes, rDNA sites, and heterochromatin distributions. Differences were observed especially in taxonomically divergent species, suggesting interspecies chromosome rearrangements.
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Affiliation(s)
- Zuzana Majtánová
- Laboratory of Fish Genetics, Institute of Animal Physiology and Genetics, Czech Academy of Sciences, 27721 Liběchov, Czech Republic;
| | - Peter J. Unmack
- Centre for Applied Water Science, Institute for Applied Ecology, University of Canberra, Bruce, ACT 2617, Australia;
| | - Tulyawat Prasongmaneerut
- Laboratory of Animal Cytogenetics and Comparative Genomics (ACCG), Department of Genetics, Faculty of Science, Kasetsart University, Bangkok 10900, Thailand; (T.P.); (K.S.)
| | - Foyez Shams
- Centre for Conservation Ecology and Genetics, Institute for Applied Ecology, University of Canberra, Bruce, ACT 2617, Australia; (F.S.); (T.E.)
| | - Kornsorn Srikulnath
- Laboratory of Animal Cytogenetics and Comparative Genomics (ACCG), Department of Genetics, Faculty of Science, Kasetsart University, Bangkok 10900, Thailand; (T.P.); (K.S.)
| | - Petr Ráb
- Laboratory of Fish Genetics, Institute of Animal Physiology and Genetics, Czech Academy of Sciences, 27721 Liběchov, Czech Republic;
| | - Tariq Ezaz
- Centre for Conservation Ecology and Genetics, Institute for Applied Ecology, University of Canberra, Bruce, ACT 2617, Australia; (F.S.); (T.E.)
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16
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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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17
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Evolutionary Variability of W-Linked Repetitive Content in Lacertid Lizards. Genes (Basel) 2020; 11:genes11050531. [PMID: 32403257 PMCID: PMC7290949 DOI: 10.3390/genes11050531] [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: 04/02/2020] [Revised: 05/04/2020] [Accepted: 05/08/2020] [Indexed: 02/07/2023] Open
Abstract
Lacertid lizards are a widely radiated group of squamate reptiles with long-term stable ZZ/ZW sex chromosomes. Despite their family-wide homology of Z-specific gene content, previous cytogenetic studies revealed significant variability in the size, morphology, and heterochromatin distribution of their W chromosome. However, there is little evidence about the accumulation and distribution of repetitive content on lacertid chromosomes, especially on their W chromosome. In order to expand our knowledge of the evolution of sex chromosome repetitive content, we examined the topology of telomeric and microsatellite motifs that tend to often accumulate on the sex chromosomes of reptiles in the karyotypes of 15 species of lacertids by fluorescence in situ hybridization (FISH). The topology of the above-mentioned motifs was compared to the pattern of heterochromatin distribution, as revealed by C-banding. Our results show that the topologies of the examined motifs on the W chromosome do not seem to follow a strong phylogenetic signal, indicating independent and species-specific accumulations. In addition, the degeneration of the W chromosome can also affect the Z chromosome and potentially also other parts of the genome. Our study provides solid evidence that the repetitive content of the degenerated sex chromosomes is one of the most evolutionary dynamic parts of the genome.
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18
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da Silva MJ, de Araújo Vieira AP, Galvão Cipriano FM, Dos Santos Cândido MR, de Oliveira EHC, Gimenez Pinheiro T, da Silva EL. The Karyotype of Salvator merianae (Squamata, Teiidae): Analyses by Classical and Molecular Cytogenetic Techniques. Cytogenet Genome Res 2020; 160:94-99. [PMID: 32062647 DOI: 10.1159/000506140] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 01/17/2020] [Indexed: 12/28/2022] Open
Abstract
In this study, we analyzed the karyotype of Salvator merianae (Teiidae) from the Brazilian semiarid region using different cytogenetic markers. Chromosomes were examined by classical (Giemsa and AgNOR staining) and molecular (FISH with ribosomal, telomeric, and microsatellite probes) cytogenetic approaches. S. merianae showed a diploid chromosome number of 2n = 38 (10 biarmed macrochromosomes + 28 microchromosomes). No sex-linked chromosome heteromorphisms were observed. Clusters of 18S/28S rDNA were localized in the terminal region of the long arm of pair 2. In addition to the typical telomeric signals, (TTAGGG)n repeats were detected in the pericentromeric region of some macrochromosome pairs, which might indicate the occurrence of chromosomal rearrangements via chromosome fusions. Hybridization signals of the microsatellite probes (GA)n, (GAA)n, and (GAG)n were uniformly distributed across all chromosomes, while (CA)n, (CAA)n, and (CAC)n produced brighter signals in the telomeric and pericentromeric regions of specific chromosome pairs. The comparison with previous studies demonstrates that, despite the wide distribution of S. merianae, the macrostructure organization of the karyotype remained unchanged, showing stability in diploid number and chromosome morphology.
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19
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Cytogenetic Analysis Did Not Reveal Differentiated Sex Chromosomes in Ten Species of Boas and Pythons (Reptilia: Serpentes). Genes (Basel) 2019; 10:genes10110934. [PMID: 31731798 PMCID: PMC6896069 DOI: 10.3390/genes10110934] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2019] [Revised: 11/11/2019] [Accepted: 11/12/2019] [Indexed: 01/16/2023] Open
Abstract
Homologous and differentiated ZZ/ZW sex chromosomes (or derived multiple neo-sex chromosomes) were often described in caenophidian snakes, but sex chromosomes were unknown until recently in non-caenophidian snakes. Previous studies revealed that two species of boas (Boa imperator, B. constrictor) and one species of python (Python bivittatus) independently evolved XX/XY sex chromosomes. In addition, heteromorphic ZZ/ZW sex chromosomes were recently revealed in the Madagascar boa (Acrantophis sp. cf. dumerili) and putatively also in the blind snake Myriopholis macrorhyncha. Since the evolution of sex chromosomes in non-caenophidian snakes seems to be more complex than previously thought, we examined ten species of pythons and boas representing the families Boidae, Calabariidae, Candoiidae, Charinidae, Pythonidae, and Sanziniidae by conventional and molecular cytogenetic methods, aiming to reveal their sex chromosomes. Our results show that all examined species do not possess sex-specific differences in their genomes detectable by the applied cytogenetic methods, indicating the presence of poorly differentiated sex chromosomes or even the absence of sex chromosomes. Interestingly, fluorescence in situ hybridization with telomeric repeats revealed extensive distribution of interstitial telomeric repeats in eight species, which are likely a consequence of intra-chromosomal rearrangements.
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20
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Majtánová Z, Indermaur A, Nyom ARB, Ráb P, Musilova Z. Adaptive Radiation from a Chromosomal Perspective: Evidence of Chromosome Set Stability in Cichlid Fishes (Cichlidae: Teleostei) from the Barombi Mbo Lake, Cameroon. Int J Mol Sci 2019; 20:ijms20204994. [PMID: 31601021 PMCID: PMC6834198 DOI: 10.3390/ijms20204994] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2019] [Revised: 10/04/2019] [Accepted: 10/07/2019] [Indexed: 12/11/2022] Open
Abstract
Cichlid fishes are the subject of scientific interest because of their rapid adaptive radiation, resulting in extensive ecological and taxonomic diversity. In this study, we examined 11 morphologically distinct cichlid species endemic to Barombi Mbo, the largest crater lake in western Cameroon, namely Konia eisentrauti, Konia dikume, Myaka myaka, Pungu maclareni, Sarotherodon steinbachi, Sarotherodon lohbergeri, Sarotherodon linnellii, Sarotherodon caroli, Stomatepia mariae, Stomatepia pindu, and Stomatepia mongo. These species supposedly evolved via sympatric ecological speciation from a common ancestor, which colonized the lake no earlier than one million years ago. Here we present the first comparative cytogenetic analysis of cichlid species from Barombi Mbo Lake using both conventional (Giemsa staining, C-banding, and CMA3/DAPI staining) and molecular (fluorescence in situ hybridization with telomeric, 5S, and 28S rDNA probes) methods. We observed stability on both macro and micro-chromosomal levels. The diploid chromosome number was 2n = 44, and the karyotype was invariably composed of three pairs of meta/submetacentric and 19 pairs of subtelo/acrocentric chromosomes in all analysed species, with the same numbers of rDNA clusters and distribution of heterochromatin. The results suggest the evolutionary stability of chromosomal set; therefore, the large-scale chromosomal rearrangements seem to be unlikely associated with the sympatric speciation in Barombi Mbo.
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Affiliation(s)
- Zuzana Majtánová
- Laboratory of Fish Genetics, Institute of Animal Physiology and Genetics, Czech Academy of Sciences, 27721 Liběchov, Czech Republic.
| | - Adrian Indermaur
- Zoological Institute, University of Basel, 4051 Basel, Switzerland.
| | - Arnold Roger Bitja Nyom
- Department of Biological Sciences, University of Ngaoundéré, Ngaoundéré P.O Box 454, Cameroon.
- Department of Management of Fisheries and Aquatic Ecosystems, University of Douala, Douala P.O Box 2701, Cameroon.
| | - Petr Ráb
- Laboratory of Fish Genetics, Institute of Animal Physiology and Genetics, Czech Academy of Sciences, 27721 Liběchov, Czech Republic.
| | - Zuzana Musilova
- Department of Zoology, Faculty of Science, Charles University in Prague, 12844 Prague, Czech Republic.
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21
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Iannucci A, Altmanová M, Ciofi C, Ferguson-Smith M, Milan M, Pereira JC, Pether J, Rehák I, Rovatsos M, Stanyon R, Velenský P, Ráb P, Kratochvíl L, Johnson Pokorná M. Conserved sex chromosomes and karyotype evolution in monitor lizards (Varanidae). Heredity (Edinb) 2019; 123:215-227. [PMID: 30670841 PMCID: PMC6781170 DOI: 10.1038/s41437-018-0179-6] [Citation(s) in RCA: 38] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2018] [Revised: 12/10/2018] [Accepted: 12/14/2018] [Indexed: 11/08/2022] Open
Abstract
Despite their long history with the basal split dating back to the Eocene, all species of monitor lizards (family Varanidae) studied so far share the same chromosome number of 2n = 40. However, there are differences in the morphology of the macrochromosome pairs 5-8. Further, sex determination, which revealed ZZ/ZW sex microchromosomes, was studied only in a few varanid species and only with techniques that did not test their homology. The aim of this study was to (i) test if cryptic interchromosomal rearrangements of larger chromosomal blocks occurred during the karyotype evolution of this group, (ii) contribute to the reconstruction of the varanid ancestral karyotype, and (iii) test homology of sex chromosomes among varanids. We investigated these issues by hybridizing flow sorted chromosome paints from Varanus komodoensis to metaphases of nine species of monitor lizards. The results show that differences in the morphology of the chromosome pairs 5-8 can be attributed to intrachromosomal rearrangements, which led to transitions between acrocentric and metacentric chromosomes in both directions. We also documented the first case of spontaneous triploidy among varanids in Varanus albigularis. The triploid individual was fully grown, which demonstrates that polyploidization is compatible with life in this lineage. We found that the W chromosome differs between species in size and heterochromatin content. The varanid Z chromosome is clearly conserved in all the analyzed species. Varanids, in addition to iguanas, caenophidian snakes, and lacertid lizards, are another squamate group with highly conserved sex chromosomes over a long evolutionary time.
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Affiliation(s)
- Alessio Iannucci
- Department of Biology, University of Florence, Via Madonna del Piano 6, 50019, Sesto Fiorentino, FI, Italy
| | - Marie Altmanová
- Department of Ecology, Charles University, Viničná 7, 128 00, Prague, Czech Republic
- Institute of Animal Physiology and Genetics, The Czech Academy of Sciences, Rumburská 89, 277 21, Liběchov, Czech Republic
| | - Claudio Ciofi
- Department of Biology, University of Florence, Via Madonna del Piano 6, 50019, Sesto Fiorentino, FI, Italy
| | - Malcolm Ferguson-Smith
- Cambridge Resource Centre for Comparative Genomics, Department of Veterinary Medicine, University of Cambridge, Madingley Road, Cambridge, CB3 0ES, United Kingdom
| | - Massimo Milan
- Department of Comparative Biomedicine and Food Science, University of Padova, Viale dell'Università 16, 35020, Legnaro, PD, Italy
| | - Jorge Claudio Pereira
- Cambridge Resource Centre for Comparative Genomics, Department of Veterinary Medicine, University of Cambridge, Madingley Road, Cambridge, CB3 0ES, United Kingdom
| | - James Pether
- Reptilandia Park, Galdar, 35460, Gran Canaria, Spain
| | - Ivan Rehák
- Prague Zoological Garden, U Trojského zámku 120/3, 171 00, Prague, Czech Republic
| | - Michail Rovatsos
- Department of Ecology, Charles University, Viničná 7, 128 00, Prague, Czech Republic
- Institute of Animal Physiology and Genetics, The Czech Academy of Sciences, Rumburská 89, 277 21, Liběchov, Czech Republic
| | - Roscoe Stanyon
- Department of Biology, University of Florence, Via Madonna del Piano 6, 50019, Sesto Fiorentino, FI, Italy
| | - Petr Velenský
- Prague Zoological Garden, U Trojského zámku 120/3, 171 00, Prague, Czech Republic
| | - Petr Ráb
- Institute of Animal Physiology and Genetics, The Czech Academy of Sciences, Rumburská 89, 277 21, Liběchov, Czech Republic
| | - Lukáš Kratochvíl
- Department of Ecology, Charles University, Viničná 7, 128 00, Prague, Czech Republic.
| | - Martina Johnson Pokorná
- Department of Ecology, Charles University, Viničná 7, 128 00, Prague, Czech Republic
- Institute of Animal Physiology and Genetics, The Czech Academy of Sciences, Rumburská 89, 277 21, Liběchov, Czech Republic
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22
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Majtánová Z, Moy KG, Unmack PJ, Ráb P, Ezaz T. Characterization of the karyotype and accumulation of repetitive sequences in Australian Darling hardyhead Craterocephalus amniculus (Atheriniformes, Teleostei). PeerJ 2019; 7:e7347. [PMID: 31392095 PMCID: PMC6677120 DOI: 10.7717/peerj.7347] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2019] [Accepted: 06/25/2019] [Indexed: 11/20/2022] Open
Abstract
Belonging to the order Atheriniformes, Craterocephalus is one of the most widespread genera of freshwater fishes in Australia, spanning along the northern coast from central Western Australia to central New South Wales and across the Murray-Darling and Lake Eyre basins. In this study, both conventional cytogenetic techniques (Giemsa, C-banding, CMA3/DAPI staining), and fluorescence in situ hybridization (FISH) with telomeric DNA and rDNA probes were used to examine the karyotypes and other chromosomal characteristics of Darling hardyhead (Craterocephalus amniculus) from New South Wales, Australia. We identified a diploid chromosome number 2n = 48 (NF = 58) in all studied individuals. FISH with rDNA probes showed a nonsyntenic pattern, with signals on one pair of subtelocentric chromosomes for 5S rDNA and one pair of submetacentric chromosomes for 28S rDNA. C-banding displayed the accumulation of constitutive heterochromatin in the centromeric regions of approximately 40 chromosomes. CMA3/DAPI fluorescence staining revealed extremely GC-rich signals in the pericentromeric region of one submetacentric chromosomal pair with size polymorphism. We detected telomeric signals at the end of all chromosomes and no interstitial signals.
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Affiliation(s)
- Zuzana Majtánová
- Laboratory of Fish Genetics, Institute of Animal Physiology and Genetics, Czech Academy of Sciences, Libechov, Czech Republic
| | - Karl G Moy
- Institute for Applied Ecology, University of Canberra, Canberra, Australian Capital Territory, Australia
| | - Peter J Unmack
- Institute for Applied Ecology, University of Canberra, Canberra, Australian Capital Territory, Australia
| | - Petr Ráb
- Laboratory of Fish Genetics, Institute of Animal Physiology and Genetics, Czech Academy of Sciences, Libechov, Czech Republic
| | - Tariq Ezaz
- Institute for Applied Ecology, University of Canberra, Canberra, Australian Capital Territory, Australia
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Xu D, Sember A, Zhu Q, Oliveira EAD, Liehr T, Al-Rikabi ABH, Xiao Z, Song H, Cioffi MDB. Deciphering the Origin and Evolution of the X 1X 2Y System in Two Closely-Related Oplegnathus Species (Oplegnathidae and Centrarchiformes). Int J Mol Sci 2019; 20:E3571. [PMID: 31336568 PMCID: PMC6678977 DOI: 10.3390/ijms20143571] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2019] [Revised: 07/05/2019] [Accepted: 07/13/2019] [Indexed: 01/18/2023] Open
Abstract
Oplegnathus fasciatus and O. punctatus (Teleostei: Centrarchiformes: Oplegnathidae), are commercially important rocky reef fishes, endemic to East Asia. Both species present an X1X2Y sex chromosome system. Here, we investigated the evolutionary forces behind the origin and differentiation of these sex chromosomes, with the aim to elucidate whether they had a single or convergent origin. To achieve this, conventional and molecular cytogenetic protocols, involving the mapping of repetitive DNA markers, comparative genomic hybridization (CGH), and whole chromosome painting (WCP) were applied. Both species presented similar 2n, karyotype structure and hybridization patterns of repetitive DNA classes. 5S rDNA loci, besides being placed on the autosomal pair 22, resided in the terminal region of the long arms of both X1 chromosomes in females, and on the X1 and Y chromosomes in males. Furthermore, WCP experiments with a probe derived from the Y chromosome of O. fasciatus (OFAS-Y) entirely painted the X1 and X2 chromosomes in females and the X1, X2, and Y chromosomes in males of both species. CGH failed to reveal any sign of sequence differentiation on the Y chromosome in both species, thereby suggesting the shared early stage of neo-Y chromosome differentiation. Altogether, the present findings confirmed the origin of the X1X2Y sex chromosomes via Y-autosome centric fusion and strongly suggested their common origin.
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Affiliation(s)
- Dongdong Xu
- Key Lab of Mariculture and Enhancement of Zhejiang Province, Marine Fishery Institute of Zhejiang Province, Zhoushan 316100, China
- College of Fisheries, Zhejiang Ocean University, Zhoushan 316100, China
| | - Alexandr Sember
- Laboratory of Fish Genetics, Institute of Animal Physiology and Genetics, Czech Academy of Sciences, Rumburská 89, 277 21 Liběchov, Czech Republic
| | - Qihui Zhu
- Key Lab of Mariculture and Enhancement of Zhejiang Province, Marine Fishery Institute of Zhejiang Province, Zhoushan 316100, China
| | - Ezequiel Aguiar de Oliveira
- Departamento de Genética e Evolução, Universidade Federal de São Carlos (UFSCar), Rodovia Washington Luiz Km. 235, C.P. 676, São Carlos SP 13565-905, Brazil
- Secretaria de Estado de Educação de Mato Grosso-SEDUC-MT, Cuiabá MT 78049-909, Brazil
| | - Thomas Liehr
- University Clinic Jena, Institute of Human Genetics, 07747 Jena, Germany
| | | | - Zhizhong Xiao
- Laboratory for Marine Biology and Biotechnology, Institute of Oceanology, Chinese Academy of Sciences, 7 Nanhai Road, Qingdao 266071, China
| | - Hongbin Song
- Key Lab of Mariculture and Enhancement of Zhejiang Province, Marine Fishery Institute of Zhejiang Province, Zhoushan 316100, China
- College of Fisheries, Zhejiang Ocean University, Zhoushan 316100, China
| | - Marcelo de Bello Cioffi
- Departamento de Genética e Evolução, Universidade Federal de São Carlos (UFSCar), Rodovia Washington Luiz Km. 235, C.P. 676, São Carlos SP 13565-905, Brazil.
- University Clinic Jena, Institute of Human Genetics, 07747 Jena, Germany.
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Pennell MW, Mank JE, Peichel CL. Transitions in sex determination and sex chromosomes across vertebrate species. Mol Ecol 2018; 27:3950-3963. [PMID: 29451715 PMCID: PMC6095824 DOI: 10.1111/mec.14540] [Citation(s) in RCA: 95] [Impact Index Per Article: 15.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2017] [Revised: 01/30/2018] [Accepted: 02/06/2018] [Indexed: 12/14/2022]
Abstract
Despite the prevalence of sexual reproduction across eukaryotes, there is a remarkable diversity of sex-determination mechanisms. The underlying causes of this diversity remain unclear, and it is unknown whether there are convergent trends in the directionality of turnover in sex-determination mechanisms. We used the recently assembled Tree of Sex database to assess patterns in the evolution of sex-determination systems in the remarkably diverse vertebrate clades of teleost fish, squamate reptiles and amphibians. Contrary to theoretical predictions, we find no evidence that the evolution of separate sexes is irreversible, as transitions from separate sexes to hermaphroditism occur at higher rates than the reverse in fish. We also find that transitions from environmental sex determination to genetic sex determination occur at higher rates than the reverse in both squamates and fish, suggesting that genetic sex determination is more stable. However, our data are not consistent with the hypothesis that heteromorphic sex chromosomes are an "evolutionary trap." Rather, we find similar transition rates between homomorphic and heteromorphic sex chromosomes in both fish and amphibians, and to environmental sex determination from heteromorphic vs. homomorphic sex chromosome systems in fish. Finally, we find that transitions between male and female heterogamety occur at similar rates in amphibians and squamates, while transitions to male heterogamety occur at higher rates in fish. Together, these results provide the most comprehensive view to date of the evolution of vertebrate sex determination in a phylogenetic context, providing new insight into long-standing questions about the evolution of sexual reproduction.
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Affiliation(s)
- Matthew W. Pennell
- Department of Zoology and Biodiversity Research Centre, University of British Columbia, Vancouver, BC, Canada
| | - Judith E. Mank
- Department of Genetics, Evolution and Environment, University College London, London, UK
- Department of Organismal Biology, Uppsala University, Sweden
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Augstenová B, Johnson Pokorná M, Altmanová M, Frynta D, Rovatsos M, Kratochvíl L. ZW, XY, and yet ZW: Sex chromosome evolution in snakes even more complicated. Evolution 2018; 72:1701-1707. [PMID: 29972583 DOI: 10.1111/evo.13543] [Citation(s) in RCA: 30] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2018] [Accepted: 06/26/2018] [Indexed: 01/07/2023]
Abstract
Snakes are historically important in the formulation of several central concepts on the evolution of sex chromosomes. For over 50 years, it was believed that all snakes shared the same ZZ/ZW sex chromosomes, which are homomorphic and poorly differentiated in "basal" snakes such as pythons and boas, while heteromorphic and well differentiated in "advanced" (caenophidian) snakes. Recent molecular studies revealed that differentiated sex chromosomes are indeed shared among all families of caenophidian snakes, but that boas and pythons evolved likely independently male heterogamety (XX/XY sex chromosomes). The historical report of heteromorphic ZZ/ZW sex chromosomes in a boid snake was previously regarded as ambiguous. In the current study, we document heteromorphic ZZ/ZW sex chromosomes in a boid snake. A comparative approach suggests that these heteromorphic sex chromosomes evolved very recently and that they are poorly differentiated at the sequence level. Interestingly, two snake lineages with confirmed male heterogamety possess homomorphic sex chromosomes, but heteromorphic sex chromosomes are present in both snake lineages with female heterogamety. We point out that this phenomenon is more common across squamates. The presence of female heterogamety in non-caenophidian snakes indicates that the evolution of sex chromosomes in this lineage is much more complex than previously thought, making snakes an even better model system for the evolution of sex chromosomes.
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Affiliation(s)
- Barbora Augstenová
- Department of Ecology, Faculty of Science, Charles University, Prague, 128 44, Czech Republic
| | - Martina Johnson Pokorná
- Department of Ecology, Faculty of Science, Charles University, Prague, 128 44, Czech Republic
- Institute of Animal Physiology and Genetics, The Czech Academy of Sciences, Liběchov, 277 21, Czech Republic
| | - Marie Altmanová
- Department of Ecology, Faculty of Science, Charles University, Prague, 128 44, Czech Republic
- Institute of Animal Physiology and Genetics, The Czech Academy of Sciences, Liběchov, 277 21, Czech Republic
| | - Daniel Frynta
- Department of Zoology, Faculty of Science, Charles University, Prague, 128 44, Czech Republic
| | - Michail Rovatsos
- Department of Ecology, Faculty of Science, Charles University, Prague, 128 44, Czech Republic
| | - Lukáš Kratochvíl
- Department of Ecology, Faculty of Science, Charles University, Prague, 128 44, Czech Republic
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Giovannotti M, Nisi Cerioni P, Rojo V, Olmo E, Slimani T, Splendiani A, Caputo Barucchi V. Characterization of a satellite DNA in the genera Lacerta andTimon(Reptilia, Lacertidae) and its role in the differentiation of the W chromosome. JOURNAL OF EXPERIMENTAL ZOOLOGY PART B-MOLECULAR AND DEVELOPMENTAL EVOLUTION 2018; 330:83-95. [DOI: 10.1002/jez.b.22790] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/12/2017] [Revised: 12/04/2017] [Accepted: 01/09/2018] [Indexed: 12/24/2022]
Affiliation(s)
- Massimo Giovannotti
- Dipartimento di Scienze della Vita e dell'Ambiente; Università Politecnica delle Marche; via Brecce Bianche Ancona Italy
| | - Paola Nisi Cerioni
- Dipartimento di Scienze della Vita e dell'Ambiente; Università Politecnica delle Marche; via Brecce Bianche Ancona Italy
| | - Verónica Rojo
- AllGenetics & Biology SL; Edificio CICA; Campus de Elviña s/n, A Coruña Spain
- Department of Molecular and Cell Biology; Evolutionary Biology Group (GIBE); Universidade da Coruña; A Fraga 10, A Coruña Spain
| | - Ettore Olmo
- Dipartimento di Scienze della Vita e dell'Ambiente; Università Politecnica delle Marche; via Brecce Bianche Ancona Italy
| | - Tahar Slimani
- Cadi Ayyad University; Faculty of Sciences Semlalia; Laboratory Biodiversity and Ecosystem Dynamics; Marrakech Morocco
| | - Andrea Splendiani
- Dipartimento di Scienze della Vita e dell'Ambiente; Università Politecnica delle Marche; via Brecce Bianche Ancona Italy
| | - Vincenzo Caputo Barucchi
- Dipartimento di Scienze della Vita e dell'Ambiente; Università Politecnica delle Marche; via Brecce Bianche Ancona Italy
- Consiglio Nazionale delle Ricerche; Istituto di Scienze Marine Sezione Pesca Marittima; Largo Fiera della Pesca; Ancona Italy
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Evolutionary Dynamics of the W Chromosome in Caenophidian Snakes. Genes (Basel) 2017; 9:genes9010005. [PMID: 29283388 PMCID: PMC5793158 DOI: 10.3390/genes9010005] [Citation(s) in RCA: 30] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2017] [Revised: 12/15/2017] [Accepted: 12/20/2017] [Indexed: 11/18/2022] Open
Abstract
The caenophidian (assigned also as “advanced”) snakes are traditionally viewed as a group of reptiles with a limited karyotypic variation and stable ZZ/ZW sex chromosomes. The W chromosomes of the caenophidian snakes are heterochromatic, and pioneering studies demonstrated that they are rich in repetitive elements. However, a comparative study of the evolutionary dynamics of the repetitive content of the W chromosome across the whole lineage is missing. Using molecular-cytogenetic techniques, we explored the distribution of four repetitive motifs (microsatellites GATA, GACA, AG and telomeric-like sequences), which are frequently accumulated in differentiated sex chromosomes in vertebrates, in the genomes of 13 species of the caenophidian snakes covering a wide phylogenetic spectrum of the lineage. The results demonstrate a striking variability in the morphology and the repetitive content of the W chromosomes even between closely-related species, which is in contrast to the homology and long-term stability of the gene content of the caenophidian Z chromosome. We uncovered that the tested microsatellite motifs are accumulated on the degenerated, heterochromatic W chromosomes in all tested species of the caenophidian snakes with the exception of the Javan file snake representing a basal clade. On the other hand, the presence of the accumulation of the telomeric-like sequences on the caenophidian W chromosome is evolutionary much less stable. Moreover, we demonstrated that large accumulations of telomeric-like motifs on the W chromosome contribute to sexual differences in the number of copies of the telomeric and telomeric-like repeats estimated by quantitative PCR, which might be confusing and incorrectly interpreted as sexual differences in telomere length.
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Evolution of Karyotypes in Chameleons. Genes (Basel) 2017; 8:genes8120382. [PMID: 29231849 PMCID: PMC5748700 DOI: 10.3390/genes8120382] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2017] [Revised: 11/29/2017] [Accepted: 11/30/2017] [Indexed: 01/04/2023] Open
Abstract
The reconstruction of the evolutionary dynamics of karyotypes and sex determining systems in squamate reptiles is precluded by the lack of data in many groups including most chameleons (Squamata: Acrodonta: Chamaeleonidae). We performed cytogenetic analysis in 16 species of chameleons from 8 genera covering the phylogenetic diversity of the family and also phylogenetic reconstruction of karyotype evolution in this group. In comparison to other squamates, chameleons demonstrate rather variable karyotypes, differing in chromosome number, morphology and presence of interstitial telomeric signal (ITS). On the other hand, the location of rDNA is quite conserved among chameleon species. Phylogenetic analysis combining our new results and previously published data tentatively suggests that the ancestral chromosome number for chameleons is 2n = 36, which is the same as assumed for other lineages of the clade Iguania, i.e., agamids and iguanas. In general, we observed a tendency for the reduction of chromosome number during the evolution of chameleons, however, in Rieppeleon brevicaudatus, we uncovered a chromosome number of 2n = 62, very unusual among squamates, originating from a number of chromosome splits. Despite the presence of the highly differentiated ZZ/ZW sex chromosomes in the genus Furcifer, we did not detect any unequivocal sexual differences in the karyotypes of any other studied species of chameleons tested using differential staining and comparative genomic hybridization, suggesting that sex chromosomes in most chameleons are only poorly differentiated.
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29
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Hormonal and thermal induction of sex reversal in the bearded dragon (Pogona vitticeps, Agamidae). ZOOL ANZ 2017. [DOI: 10.1016/j.jcz.2017.11.002] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
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30
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Rovatsos M, Altmanová M, Johnson Pokorná M, Augstenová B, Kratochvíl L. Cytogenetics of the Javan file snake (Acrochordus javanicus
) and the evolution of snake sex chromosomes. J ZOOL SYST EVOL RES 2017. [DOI: 10.1111/jzs.12180] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Affiliation(s)
- Michail Rovatsos
- Department of Ecology; Faculty of Science; Charles University; Prague Czech Republic
| | - Marie Altmanová
- Department of Ecology; Faculty of Science; Charles University; Prague Czech Republic
- Institute of Animal Physiology and Genetics; The Czech Academy of Sciences; Liběchov Czech Republic
| | - Martina Johnson Pokorná
- Department of Ecology; Faculty of Science; Charles University; Prague Czech Republic
- Institute of Animal Physiology and Genetics; The Czech Academy of Sciences; Liběchov Czech Republic
| | - Barbora Augstenová
- Department of Ecology; Faculty of Science; Charles University; Prague Czech Republic
| | - Lukáš Kratochvíl
- Department of Ecology; Faculty of Science; Charles University; Prague Czech Republic
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31
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Rovatsos M, Praschag P, Fritz U, Kratochvšl L. Stable Cretaceous sex chromosomes enable molecular sexing in softshell turtles (Testudines: Trionychidae). Sci Rep 2017; 7:42150. [PMID: 28186115 PMCID: PMC5301483 DOI: 10.1038/srep42150] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2016] [Accepted: 01/05/2017] [Indexed: 01/18/2023] Open
Abstract
Turtles demonstrate variability in sex determination ranging from environmental sex determination (ESD) to highly differentiated sex chromosomes. However, the evolutionary dynamics of sex determining systems in this group is not well known. Differentiated ZZ/ZW sex chromosomes were identified in two species of the softshell turtles (Trionychidae) from the subfamily Trionychinae and Z-specific genes were identified in a single species. We tested Z-specificity of a subset of these genes by quantitative PCR comparing copy gene numbers in male and female genomes in 10 species covering the phylogenetic diversity of trionychids. We demonstrated that differentiated ZZ/ZW sex chromosomes are conserved across the whole family and that they were already present in the common ancestor of the extant trionychids. As the sister lineage, Carettochelys insculpta, possess ESD, we can date the origin of the sex chromosomes in trionychids between 200 Mya (split of Trionychidae and Carettochelyidae) and 120 Mya (basal splitting of the recent trionychids). The results support the evolutionary stability of differentiated sex chromosomes in some lineages of ectothermic vertebrates. Moreover, our approach determining sex-linkage of protein coding genes can be used as a reliable technique of molecular sexing across trionychids useful for effective breeding strategy in conservation projects of endangered species.
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Affiliation(s)
- Michail Rovatsos
- Faculty of Science, Charles University, Department of Ecology, Viničná 7, 12844 Praha 2, Czech Republic
| | - Peter Praschag
- Turtle Island, Turtle Conservation Center, Am Katzelbach 98, 8054 Graz, Austria
| | - Uwe Fritz
- Museum of Zoology, Senckenberg Dresden, A. B. Meyer Building, 01109 Dresden, Germany
| | - Lukáš Kratochvšl
- Faculty of Science, Charles University, Department of Ecology, Viničná 7, 12844 Praha 2, Czech Republic
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32
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Rovatsos M, Kratochvíl L. Molecular sexing applicable in 4000 species of lizards and snakes? From dream to real possibility. Methods Ecol Evol 2017. [DOI: 10.1111/2041-210x.12714] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Affiliation(s)
- Michail Rovatsos
- Department of Ecology Faculty of Science Charles University in Prague Viničná 7 12844 Prague Czech Republic
| | - Lukáš Kratochvíl
- Department of Ecology Faculty of Science Charles University in Prague Viničná 7 12844 Prague Czech Republic
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33
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Majtánová Z, Symonová R, Arias-Rodriguez L, Sallan L, Ráb P. "Holostei versus Halecostomi" Problem: Insight from Cytogenetics of Ancient Nonteleost Actinopterygian Fish, Bowfin Amia calva. JOURNAL OF EXPERIMENTAL ZOOLOGY PART B-MOLECULAR AND DEVELOPMENTAL EVOLUTION 2017; 328:620-628. [PMID: 28074622 DOI: 10.1002/jez.b.22720] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/27/2016] [Revised: 09/12/2016] [Accepted: 11/22/2016] [Indexed: 12/17/2022]
Abstract
Bowfin belongs to an ancient lineage of nonteleost ray-finned fishes (actinopterygians) and is the only extant survivor of a once diverged group, the Halecomorphi or Amiiformes. Owing to the scarcity of extant nonteleost ray-finned lineages, also referred as "living fossils," their phylogenetic interrelationships have been the target of multiple hypotheses concerning their sister group relationships. Molecular and morphological data sets have produced controversial results; bowfin is considered as either the sister group to genome-duplicated teleosts (together forming the group of Halecostomi) or to gars (Lepisosteiformes; together forming the group of Holostei). However, any detailed cytogenetic analysis of bowfin chromosomes has never been performed to address this issue. Here we examined bowfin chromosomes by conventional (Giemsa-staining, C-banding, base-specific fluorescence and silver staining) and molecular (FISH with rDNA probes) cytogenetic protocols. We identified diploid chromosome number 2n = 46 with a middle-sized submetacentric chromosome pair as the major ribosomal DNA-bearing (45S rDNA), GC-positive and silver-positive element. The minor rDNA (5S rDNA) sites were localized in the pericentromeric region of one middle-sized acrocentric chromosome pair. Comparison with available cytogenetic data of other nonteleost actinopterygians (bichirs, sturgeons, gars) and teleost species including representative of basally branching lineages showed bowfin chromosomal characteristics more similar to the teleost type than to any other nonteleosts. Particularly striking differences were identified between bowfin and gars, the latter of which were found to mimic mammalian AT/GC genomic organisation. Such conclusion however contradicts the most recent phylogenomic results and raises the question what states are ancestral and what are derived.
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Affiliation(s)
- Zuzana Majtánová
- Laboratory of Fish Genetics, Institute of Animal Physiology and Genetics, Academy of Sciences of the Czech Republic, Liběchov, Czech Republic.,Department of Zoology, Faculty of Science, Charles University in Prague, Prague 2, Czech Republic
| | - Radka Symonová
- Laboratory of Fish Genetics, Institute of Animal Physiology and Genetics, Academy of Sciences of the Czech Republic, Liběchov, Czech Republic.,Research Institute for Limnology, University of Innsbruck, Mondsee, Austria
| | - Lenin Arias-Rodriguez
- División Académica de Ciencias Biológicas, Universidad Juárez Autónoma de Tabasco (UJAT), Villahermosa, Tabasco, México
| | - Lauren Sallan
- Department of Earth and Environmental Science, University of Pennsylvania, Philadelphia, Pennsylvania
| | - Petr Ráb
- Laboratory of Fish Genetics, Institute of Animal Physiology and Genetics, Academy of Sciences of the Czech Republic, Liběchov, Czech Republic
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Symonová R, Majtánová Z, Arias-Rodriguez L, Mořkovský L, Kořínková T, Cavin L, Pokorná MJ, Doležálková M, Flajšhans M, Normandeau E, Ráb P, Meyer A, Bernatchez L. Genome Compositional Organization in Gars Shows More Similarities to Mammals than to Other Ray-Finned Fish. JOURNAL OF EXPERIMENTAL ZOOLOGY PART B-MOLECULAR AND DEVELOPMENTAL EVOLUTION 2016; 328:607-619. [DOI: 10.1002/jez.b.22719] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/17/2016] [Revised: 11/13/2016] [Accepted: 11/22/2016] [Indexed: 12/12/2022]
Affiliation(s)
- Radka Symonová
- Laboratory of Fish Genetics; Institute of Animal Physiology and Genetics; The Czech Academy of Sciences; Liběchov Czech Republic
- Department of Zoology; Faculty of Science; Charles University; Prague 2 Czech Republic
- Research Institute for Limnology; University of Innsbruck; Mondsee Austria
| | - Zuzana Majtánová
- Laboratory of Fish Genetics; Institute of Animal Physiology and Genetics; The Czech Academy of Sciences; Liběchov Czech Republic
- Department of Zoology; Faculty of Science; Charles University; Prague 2 Czech Republic
| | - Lenin Arias-Rodriguez
- División Académica de Ciencias Biológicas; Universidad Juárez Autónoma de Tabasco (UJAT); Villahermosa Tabasco México
| | - Libor Mořkovský
- Department of Zoology; Faculty of Science; Charles University; Prague 2 Czech Republic
| | - Tereza Kořínková
- Laboratory of Fish Genetics; Institute of Animal Physiology and Genetics; The Czech Academy of Sciences; Liběchov Czech Republic
| | - Lionel Cavin
- Muséum d'Histoire Naturelle; Geneva 6 Switzerland
| | - Martina Johnson Pokorná
- Laboratory of Fish Genetics; Institute of Animal Physiology and Genetics; The Czech Academy of Sciences; Liběchov Czech Republic
- Department of Ecology; Faculty of Science; Charles University; Prague 2 Czech Republic
| | - Marie Doležálková
- Laboratory of Fish Genetics; Institute of Animal Physiology and Genetics; The Czech Academy of Sciences; Liběchov Czech Republic
- Department of Zoology; Faculty of Science; Charles University; Prague 2 Czech Republic
| | - Martin Flajšhans
- Faculty of Fisheries and Protection of Waters; South Bohemian Research Centre of Aquaculture and Biodiversity of Hydrocenoses; University of South Bohemia in České Budějovice; Vodňany Czech Republic
| | - Eric Normandeau
- IBIS, Department of Biology, University Laval, Pavillon Charles-Eugène-Marchand; Avenue de la Médecine Quebec City; Canada
| | - Petr Ráb
- Laboratory of Fish Genetics; Institute of Animal Physiology and Genetics; The Czech Academy of Sciences; Liběchov Czech Republic
| | - Axel Meyer
- Chair in Zoology and Evolutionary Biology; Department of Biology; University of Konstanz; Konstanz Germany
| | - Louis Bernatchez
- IBIS, Department of Biology, University Laval, Pavillon Charles-Eugène-Marchand; Avenue de la Médecine Quebec City; Canada
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Rovatsos M, Johnson Pokorná M, Altmanová M, Kratochvíl L. Mixed-Up Sex Chromosomes: Identification of Sex Chromosomes in the X1X1X2X2/X1X2Y System of the Legless Lizards of the Genus Lialis (Squamata: Gekkota: Pygopodidae). Cytogenet Genome Res 2016; 149:282-289. [DOI: 10.1159/000450734] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/05/2016] [Indexed: 11/19/2022] Open
Abstract
Geckos in general show extensive variability in sex determining systems, but only male heterogamety has been demonstrated in the members of their legless family Pygopodidae. In the pioneering study published more than 45 years ago, multiple sex chromosomes of the type X1X1X2X2/X1X2Y were described in Burton's legless lizard (Lialisburtonis) based on conventional cytogenetic techniques. We conducted cytogenetic analyses including comparative genomic hybridization and fluorescence in situ hybridization (FISH) with selected cytogenetic markers in this species and the previously cytogenetically unstudied Papua snake lizard (Lialis jicari) to better understand the nature of these sex chromosomes and their differentiation. Both species possess male heterogamety with an X1X1X2X2/X1X2Y sex chromosome system; however, the Y and one of the X chromosomes are not small chromosomes as previously reported in L. burtonis, but the largest macrochromosomal pair in the karyotype. The Y chromosomes in both species have large heterochromatic blocks with extensive accumulations of GATA and AC microsatellite motifs. FISH with telomeric probe revealed an exclusively terminal position of telomeric sequences in L. jicari (2n = 42 chromosomes in females), but extensive interstitial signals, potentially remnants of chromosomal fusions, in L.burtonis (2n = 34 in females). Our study shows that even largely differentiated and heteromorphic sex chromosomes might be misidentified by conventional cytogenetic analyses and that the application of more sensitive cytogenetic techniques for the identification of sex chromosomes is beneficial even in the classical examples of multiple sex chromosomes.
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Johnson Pokorná M, Altmanová M, Rovatsos M, Velenský P, Vodička R, Rehák I, Kratochvíl L. First Description of the Karyotype and Sex Chromosomes in the Komodo Dragon (Varanus komodoensis). Cytogenet Genome Res 2016; 148:284-91. [DOI: 10.1159/000447340] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 03/14/2016] [Indexed: 11/19/2022] Open
Abstract
The Komodo dragon (Varanus komodoensis) is the largest lizard in the world. Surprisingly, it has not yet been cytogenetically examined. Here, we present the very first description of its karyotype and sex chromosomes. The karyotype consists of 2n = 40 chromosomes, 16 macrochromosomes and 24 microchromosomes. Although the chromosome number is constant for all species of monitor lizards (family Varanidae) with the currently reported karyotype, variability in the morphology of the macrochromosomes has been previously documented within the group. We uncovered highly differentiated ZZ/ZW sex microchromosomes with a heterochromatic W chromosome in the Komodo dragon. Sex chromosomes have so far only been described in a few species of varanids including V. varius, the sister species to Komodo dragon, whose W chromosome is notably larger than that of the Komodo dragon. Accumulations of several microsatellite sequences in the W chromosome have recently been detected in 3 species of monitor lizards; however, these accumulations are absent from the W chromosome of the Komodo dragon. In conclusion, although varanids are rather conservative in karyotypes, their W chromosomes exhibit substantial variability at the sequence level, adding further evidence that degenerated sex chromosomes may represent the most dynamic genome part.
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Altmanová M, Rovatsos M, Kratochvíl L, Johnson Pokorná M. Minute Y chromosomes and karyotype evolution in Madagascan iguanas (Squamata: Iguania: Opluridae). Biol J Linn Soc Lond 2016. [DOI: 10.1111/bij.12751 10.1080/11250000409356641] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Affiliation(s)
- Marie Altmanová
- Faculty of Science; Department of Ecology; Charles University in Prague; Viničná 7 Praha 2 Czech Republic
| | - Michail Rovatsos
- Faculty of Science; Department of Ecology; Charles University in Prague; Viničná 7 Praha 2 Czech Republic
| | - Lukáš Kratochvíl
- Faculty of Science; Department of Ecology; Charles University in Prague; Viničná 7 Praha 2 Czech Republic
| | - Martina Johnson Pokorná
- Faculty of Science; Department of Ecology; Charles University in Prague; Viničná 7 Praha 2 Czech Republic
- Institute of Animal Physiology and Genetics; The Czech Academy of Sciences; Rumburská 89 Liběchov Czech Republic
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Sabath N, Itescu Y, Feldman A, Meiri S, Mayrose I, Valenzuela N. Sex determination, longevity, and the birth and death of reptilian species. Ecol Evol 2016; 6:5207-20. [PMID: 27551377 PMCID: PMC4984498 DOI: 10.1002/ece3.2277] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2016] [Revised: 06/01/2016] [Accepted: 06/03/2016] [Indexed: 11/08/2022] Open
Abstract
Vertebrate sex-determining mechanisms (SDMs) are triggered by the genotype (GSD), by temperature (TSD), or occasionally, by both. The causes and consequences of SDM diversity remain enigmatic. Theory predicts SDM effects on species diversification, and life-span effects on SDM evolutionary turnover. Yet, evidence is conflicting in clades with labile SDMs, such as reptiles. Here, we investigate whether SDM is associated with diversification in turtles and lizards, and whether alterative factors, such as lifespan's effect on transition rates, could explain the relative prevalence of SDMs in turtles and lizards (including and excluding snakes). We assembled a comprehensive dataset of SDM states for squamates and turtles and leveraged large phylogenies for these two groups. We found no evidence that SDMs affect turtle, squamate, or lizard diversification. However, SDM transition rates differ between groups. In lizards TSD-to-GSD surpass GSD-to-TSD transitions, explaining the predominance of GSD lizards in nature. SDM transitions are fewer in turtles and the rates are similar to each other (TSD-to-GSD equals GSD-to-TSD), which, coupled with TSD ancestry, could explain TSD's predominance in turtles. These contrasting patterns can be explained by differences in life history. Namely, our data support the notion that in general, shorter lizard lifespan renders TSD detrimental favoring GSD evolution in squamates, whereas turtle longevity permits TSD retention. Thus, based on the macro-evolutionary evidence we uncovered, we hypothesize that turtles and lizards followed different evolutionary trajectories with respect to SDM, likely mediated by differences in lifespan. Combined, our findings revealed a complex evolutionary interplay between SDMs and life histories that warrants further research that should make use of expanded datasets on unexamined taxa to enable more conclusive analyses.
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Affiliation(s)
- Niv Sabath
- Department of Molecular Biology and Ecology of Plants Tel Aviv University Tel Aviv 69978 Israel
| | - Yuval Itescu
- Department of Zoology Tel Aviv University Tel Aviv 69978 Israel
| | - Anat Feldman
- Department of Zoology Tel Aviv University Tel Aviv 69978 Israel
| | - Shai Meiri
- Department of Zoology Tel Aviv University Tel Aviv 69978 Israel
| | - Itay Mayrose
- Department of Molecular Biology and Ecology of Plants Tel Aviv University Tel Aviv 69978 Israel
| | - Nicole Valenzuela
- Department of Ecology, Evolution and Organismal Biology Iowa State University Ames Iowa 50011
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Rovatsos M, Vukić J, Altmanová M, Johnson Pokorná M, Moravec J, Kratochvíl L. Conservation of sex chromosomes in lacertid lizards. Mol Ecol 2016; 25:3120-6. [DOI: 10.1111/mec.13635] [Citation(s) in RCA: 46] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2015] [Revised: 03/07/2016] [Accepted: 03/22/2016] [Indexed: 01/26/2023]
Affiliation(s)
- Michail Rovatsos
- Department of Ecology; Faculty of Science; Charles University in Prague; Viničná 7 128 44 Prague Czech Republic
| | - Jasna Vukić
- Department of Ecology; Faculty of Science; Charles University in Prague; Viničná 7 128 44 Prague Czech Republic
| | - Marie Altmanová
- Department of Ecology; Faculty of Science; Charles University in Prague; Viničná 7 128 44 Prague Czech Republic
| | - Martina Johnson Pokorná
- Department of Ecology; Faculty of Science; Charles University in Prague; Viničná 7 128 44 Prague Czech Republic
- Institute of Animal Physiology and Genetics; The Czech Academy of Sciences; Liběchov Czech Republic
| | - Jiří Moravec
- Department of Zoology; National Museum; Václavské nám. 68 115 79 Prague Czech Republic
| | - Lukáš Kratochvíl
- Department of Ecology; Faculty of Science; Charles University in Prague; Viničná 7 128 44 Prague Czech Republic
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Discovery of the youngest sex chromosomes reveals first case of convergent co-option of ancestral autosomes in turtles. Chromosoma 2016; 126:105-113. [DOI: 10.1007/s00412-016-0576-7] [Citation(s) in RCA: 42] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2015] [Revised: 01/21/2016] [Accepted: 01/22/2016] [Indexed: 11/27/2022]
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Altmanová M, Rovatsos M, Kratochvíl L, Johnson Pokorná M. Minute Y chromosomes and karyotype evolution in Madagascan iguanas (Squamata: Iguania: Opluridae). Biol J Linn Soc Lond 2016. [DOI: 10.1111/bij.12751] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Affiliation(s)
- Marie Altmanová
- Faculty of Science; Department of Ecology; Charles University in Prague; Viničná 7 Praha 2 Czech Republic
| | - Michail Rovatsos
- Faculty of Science; Department of Ecology; Charles University in Prague; Viničná 7 Praha 2 Czech Republic
| | - Lukáš Kratochvíl
- Faculty of Science; Department of Ecology; Charles University in Prague; Viničná 7 Praha 2 Czech Republic
| | - Martina Johnson Pokorná
- Faculty of Science; Department of Ecology; Charles University in Prague; Viničná 7 Praha 2 Czech Republic
- Institute of Animal Physiology and Genetics; The Czech Academy of Sciences; Rumburská 89 Liběchov Czech Republic
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Majtánová Z, Choleva L, Symonová R, Ráb P, Kotusz J, Pekárik L, Janko K. Asexual Reproduction Does Not Apparently Increase the Rate of Chromosomal Evolution: Karyotype Stability in Diploid and Triploid Clonal Hybrid Fish (Cobitis, Cypriniformes, Teleostei). PLoS One 2016; 11:e0146872. [PMID: 26808475 PMCID: PMC4726494 DOI: 10.1371/journal.pone.0146872] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2014] [Accepted: 12/25/2015] [Indexed: 12/23/2022] Open
Abstract
Interspecific hybridization, polyploidization and transitions from sexuality to asexuality considerably affect organismal genomes. Especially the last mentioned process has been assumed to play a significant role in the initiation of chromosomal rearrangements, causing increased rates of karyotype evolution. We used cytogenetic analysis and molecular dating of cladogenetic events to compare the rate of changes of chromosome morphology and karyotype in asexually and sexually reproducing counterparts in European spined loach fish (Cobitis). We studied metaphases of three sexually reproducing species and their diploid and polyploid hybrid clones of different age of origin. The material includes artificial F1 hybrid strains, representatives of lineage originated in Holocene epoch, and also individuals of an oldest known age to date (roughly 0.37 MYA). Thereafter we applied GISH technique as a marker to differentiate parental chromosomal sets in hybrids. Although the sexual species accumulated remarkable chromosomal rearrangements after their speciation, we observed no differences in chromosome numbers and/or morphology among karyotypes of asexual hybrids. These hybrids possess chromosome sets originating from respective parental species with no cytogenetically detectable recombinations, suggesting their integrity even in a long term. The switch to asexual reproduction thus did not provoke any significant acceleration of the rate of chromosomal evolution in Cobitis. Asexual animals described in other case studies reproduce ameiotically, while Cobitis hybrids described here produce eggs likely through modified meiosis. Therefore, our findings indicate that the effect of asexuality on the rate of chromosomal change may be context-dependent rather than universal and related to particular type of asexual reproduction.
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Affiliation(s)
- Zuzana Majtánová
- Laboratory of Fish Genetics, Institute of Animal Physiology and Genetics, CAS, v.v.i, Liběchov, Czech Republic
- Department of Zoology, Faculty of Science, Charles University in Prague, Prague, Czech Republic
- * E-mail:
| | - Lukáš Choleva
- Laboratory of Fish Genetics, Institute of Animal Physiology and Genetics, CAS, v.v.i, Liběchov, Czech Republic
- Department of Biology and Ecology, Faculty of Science, University of Ostrava, Ostrava, Czech Republic
| | - Radka Symonová
- Laboratory of Fish Genetics, Institute of Animal Physiology and Genetics, CAS, v.v.i, Liběchov, Czech Republic
- Research Institute for Limnology, University of Innsbruck, Mondsee, Austria
| | - Petr Ráb
- Laboratory of Fish Genetics, Institute of Animal Physiology and Genetics, CAS, v.v.i, Liběchov, Czech Republic
| | - Jan Kotusz
- Museum of Natural History, University of Wrocław, Wrocław, Poland
| | - Ladislav Pekárik
- Institute of Botany, SAS, Bratislava, Slovakia
- Department of Biology, Faculty of Education, Trnava University, Trnava, Slovakia
| | - Karel Janko
- Laboratory of Fish Genetics, Institute of Animal Physiology and Genetics, CAS, v.v.i, Liběchov, Czech Republic
- Department of Biology and Ecology, Faculty of Science, University of Ostrava, Ostrava, Czech Republic
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Dynamics of vertebrate sex chromosome evolution: from equal size to giants and dwarfs. Chromosoma 2015; 125:553-71. [DOI: 10.1007/s00412-015-0569-y] [Citation(s) in RCA: 71] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2015] [Revised: 12/09/2015] [Accepted: 12/10/2015] [Indexed: 11/26/2022]
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Evans BJ, Carter TF, Greenbaum E, Gvoždík V, Kelley DB, McLaughlin PJ, Pauwels OSG, Portik DM, Stanley EL, Tinsley RC, Tobias ML, Blackburn DC. Genetics, Morphology, Advertisement Calls, and Historical Records Distinguish Six New Polyploid Species of African Clawed Frog (Xenopus, Pipidae) from West and Central Africa. PLoS One 2015; 10:e0142823. [PMID: 26672747 PMCID: PMC4682732 DOI: 10.1371/journal.pone.0142823] [Citation(s) in RCA: 63] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2015] [Accepted: 10/27/2015] [Indexed: 01/08/2023] Open
Abstract
African clawed frogs, genus Xenopus, are extraordinary among vertebrates in the diversity of their polyploid species and the high number of independent polyploidization events that occurred during their diversification. Here we update current understanding of the evolutionary history of this group and describe six new species from west and central sub-Saharan Africa, including four tetraploids and two dodecaploids. We provide information on molecular variation, morphology, karyotypes, vocalizations, and estimated geographic ranges, which support the distinctiveness of these new species. We resurrect Xenopus calcaratus from synonymy of Xenopus tropicalis and refer populations from Bioko Island and coastal Cameroon (near Mt. Cameroon) to this species. To facilitate comparisons to the new species, we also provide comments on the type specimens, morphology, and distributions of X. epitropicalis, X. tropicalis, and X. fraseri. This includes significantly restricted application of the names X. fraseri and X. epitropicalis, the first of which we argue is known definitively only from type specimens and possibly one other specimen. Inferring the evolutionary histories of these new species allows refinement of species groups within Xenopus and leads to our recognition of two subgenera (Xenopus and Silurana) and three species groups within the subgenus Xenopus (amieti, laevis, and muelleri species groups).
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Affiliation(s)
- Ben J. Evans
- Department of Biology, Life Sciences Building Room 328 McMaster University, Hamilton, Ontario, Canada
- * E-mail:
| | - Timothy F. Carter
- Biomedical Sciences, Ontario Veterinary College, University of Guelph, Guelph, Ontario, Canada
| | - Eli Greenbaum
- Department of Biological Sciences, University of Texas at El Paso, El Paso, Texas, United States of America
| | - Václav Gvoždík
- Institute of Vertebrate Biology, Czech Academy of Sciences, Kvetna 8, Brno, Czech Republic
- Department of Zoology, National Museum, Prague, Czech Republic
| | - Darcy B. Kelley
- Department of Biological Sciences, Columbia University, New York, New York, United States of America
| | - Patrick J. McLaughlin
- Department of Biology, Papadakis Integrated Sciences Building, Drexel University, Philadelphia, Pennsylvania, United States of America
| | - Olivier S. G. Pauwels
- Département des Vertébrés Récents, Instítut Royal des Sciences Naturelles de Belgique, Brussels, Belgium
| | - Daniel M. Portik
- Museum of Vertebrate Zoology, University of California, Berkeley, California, United States of America
| | - Edward L. Stanley
- California Academy of Sciences, San Francisco, California, United States of America
| | - Richard C. Tinsley
- School of Biological Sciences, University of Bristol, Bristol, United Kingdom
| | | | - David C. Blackburn
- California Academy of Sciences, San Francisco, California, United States of America
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Rovatsos M, Johnson Pokorná M, Kratochvíl L. Differentiation of Sex Chromosomes and Karyotype Characterisation in the Dragonsnake Xenodermus javanicus (Squamata: Xenodermatidae). Cytogenet Genome Res 2015; 147:48-54. [DOI: 10.1159/000441646] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2015] [Indexed: 11/19/2022] Open
Abstract
Highly differentiated heteromorphic ZZ/ZW sex chromosomes with a heterochromatic W are a basic principle among advanced snakes of the lineage Colubroidea, while other snake lineages generally lack these characteristics. For the first time, we cytogenetically examined the dragonsnake, Xenodermus javanicus, a member of the family Xenodermatidae, which is phylogenetically nested between snake lineages with and without differentiated sex chromosomes. Although most snakes have a karyotype with a stable chromosomal number of 2n = 36, the dragonsnake has an unusual, derived karyotype with 2n = 32 chromosomes. We found that heteromorphic ZZ/ZW sex chromosomes with a heterochromatic W are present in the dragonsnake, which suggests that the emergence of a highly differentiated W sex chromosome within snakes predates the split of Xenodermatidae and the clade including families Pareatidae, Viperidae, Homalopsidae, Lamprophiidae, Elapidae, and Colubridae. Although accumulations of interstitial telomeric sequences have not been previously reported in snakes, by using FISH with a telomeric probe we discovered them in 6 pairs of autosomes as well as in the W sex chromosome of the dragonsnake. Similarly to advanced snakes, the sex chromosomes of the dragonsnake have a significant accumulation of repeats containing a (GATA)n sequence. The results facilitate the dating of the differentiation of sex chromosomes within snakes back to the split between Xenodermatidae and other advanced snakes, i.e. around 40-75 mya.
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Matsubara K, Uno Y, Srikulnath K, Matsuda Y, Miller E, Olsson M. No Interstitial Telomeres on Autosomes but Remarkable Amplification of Telomeric Repeats on the W Sex Chromosome in the Sand Lizard (Lacerta agilis). ACTA ACUST UNITED AC 2015; 106:753-7. [PMID: 26464091 DOI: 10.1093/jhered/esv083] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2015] [Accepted: 09/25/2015] [Indexed: 11/13/2022]
Abstract
Telomeres are repeat (TTAGGG) n sequences that form terminal ends of chromosomes and have several functions, such as protecting the coding DNA from erosion at mitosis. Due to chromosomal rearrangements through evolutionary history (e.g., inversions and fusions), telomeric sequences are also found between the centromere and the terminal ends (i.e., at interstitial telomeric sites, ITSs). ITS telomere sequences have been implicated in heritable disease caused by genomic instability of ITS polymorphic variants, both with respect to copy number and sequence. In the sand lizard (Lacerta agilis), we have shown that telomere length is predictive of lifetime fitness in females but not males. To assess whether this sex specific fitness effect could be traced to ITSs differences, we mapped (TTAGGG) n sequences using fluorescence in situ hybridization in fibroblast cells cultured from 4 specimens of known sex. No ITSs could be found on autosomes in either sex. However, females have heterogametic sex chromosomes in sand lizards (ZW, 2n = 38) and the female W chromosome showed degeneration and remarkable (TTAGGG) n amplification, which was absent in the Z chromosomes. This work warrants further research on sex chromosome content, in particular of the degenerate W chromosome, and links to female fitness in sand lizards.
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Affiliation(s)
- Kazumi Matsubara
- From the Laboratory of Animal Genetics, Department of Applied Molecular Biosciences, Graduate School of Bioagricultural Sciences, Nagoya University, Furo-cho, Chikusa-ku, Nagoya, Japan (Matsubara, Uno, Srikulnath, and Matsuda); Department of Information and Biological Sciences, Graduate School of Natural Sciences, Nagoya City University, Nagoya, Japan (Matsubara); Laboratory of Animal Cytogenetics & Comparative Genomics, Department of Genetics, Faculty of Science, Kasetsart University, Bangkok, Thailand (Srikulnath); Avian Bioscience Research Center, Graduate School of Bioagricultural Sciences, Nagoya University, Nagoya, Japan (Matsuda); Sydney Medical School QEII Research Institute for Mothers and Infants D02, The University of Sydney , NSW 2006, Australia (Miller); School of Biological Sciences, The University of Sydney, Heydon-Laurence Building A08, NSW 2006, Australia (Olsson); and Department of Biological and Environmental Sciences, University of Gothenburg, Gothenburg, Sweden (Olsson)
| | - Yoshinobu Uno
- From the Laboratory of Animal Genetics, Department of Applied Molecular Biosciences, Graduate School of Bioagricultural Sciences, Nagoya University, Furo-cho, Chikusa-ku, Nagoya, Japan (Matsubara, Uno, Srikulnath, and Matsuda); Department of Information and Biological Sciences, Graduate School of Natural Sciences, Nagoya City University, Nagoya, Japan (Matsubara); Laboratory of Animal Cytogenetics & Comparative Genomics, Department of Genetics, Faculty of Science, Kasetsart University, Bangkok, Thailand (Srikulnath); Avian Bioscience Research Center, Graduate School of Bioagricultural Sciences, Nagoya University, Nagoya, Japan (Matsuda); Sydney Medical School QEII Research Institute for Mothers and Infants D02, The University of Sydney , NSW 2006, Australia (Miller); School of Biological Sciences, The University of Sydney, Heydon-Laurence Building A08, NSW 2006, Australia (Olsson); and Department of Biological and Environmental Sciences, University of Gothenburg, Gothenburg, Sweden (Olsson)
| | - Kornsorn Srikulnath
- From the Laboratory of Animal Genetics, Department of Applied Molecular Biosciences, Graduate School of Bioagricultural Sciences, Nagoya University, Furo-cho, Chikusa-ku, Nagoya, Japan (Matsubara, Uno, Srikulnath, and Matsuda); Department of Information and Biological Sciences, Graduate School of Natural Sciences, Nagoya City University, Nagoya, Japan (Matsubara); Laboratory of Animal Cytogenetics & Comparative Genomics, Department of Genetics, Faculty of Science, Kasetsart University, Bangkok, Thailand (Srikulnath); Avian Bioscience Research Center, Graduate School of Bioagricultural Sciences, Nagoya University, Nagoya, Japan (Matsuda); Sydney Medical School QEII Research Institute for Mothers and Infants D02, The University of Sydney , NSW 2006, Australia (Miller); School of Biological Sciences, The University of Sydney, Heydon-Laurence Building A08, NSW 2006, Australia (Olsson); and Department of Biological and Environmental Sciences, University of Gothenburg, Gothenburg, Sweden (Olsson)
| | - Yoichi Matsuda
- From the Laboratory of Animal Genetics, Department of Applied Molecular Biosciences, Graduate School of Bioagricultural Sciences, Nagoya University, Furo-cho, Chikusa-ku, Nagoya, Japan (Matsubara, Uno, Srikulnath, and Matsuda); Department of Information and Biological Sciences, Graduate School of Natural Sciences, Nagoya City University, Nagoya, Japan (Matsubara); Laboratory of Animal Cytogenetics & Comparative Genomics, Department of Genetics, Faculty of Science, Kasetsart University, Bangkok, Thailand (Srikulnath); Avian Bioscience Research Center, Graduate School of Bioagricultural Sciences, Nagoya University, Nagoya, Japan (Matsuda); Sydney Medical School QEII Research Institute for Mothers and Infants D02, The University of Sydney , NSW 2006, Australia (Miller); School of Biological Sciences, The University of Sydney, Heydon-Laurence Building A08, NSW 2006, Australia (Olsson); and Department of Biological and Environmental Sciences, University of Gothenburg, Gothenburg, Sweden (Olsson)
| | - Emily Miller
- From the Laboratory of Animal Genetics, Department of Applied Molecular Biosciences, Graduate School of Bioagricultural Sciences, Nagoya University, Furo-cho, Chikusa-ku, Nagoya, Japan (Matsubara, Uno, Srikulnath, and Matsuda); Department of Information and Biological Sciences, Graduate School of Natural Sciences, Nagoya City University, Nagoya, Japan (Matsubara); Laboratory of Animal Cytogenetics & Comparative Genomics, Department of Genetics, Faculty of Science, Kasetsart University, Bangkok, Thailand (Srikulnath); Avian Bioscience Research Center, Graduate School of Bioagricultural Sciences, Nagoya University, Nagoya, Japan (Matsuda); Sydney Medical School QEII Research Institute for Mothers and Infants D02, The University of Sydney , NSW 2006, Australia (Miller); School of Biological Sciences, The University of Sydney, Heydon-Laurence Building A08, NSW 2006, Australia (Olsson); and Department of Biological and Environmental Sciences, University of Gothenburg, Gothenburg, Sweden (Olsson)
| | - Mats Olsson
- From the Laboratory of Animal Genetics, Department of Applied Molecular Biosciences, Graduate School of Bioagricultural Sciences, Nagoya University, Furo-cho, Chikusa-ku, Nagoya, Japan (Matsubara, Uno, Srikulnath, and Matsuda); Department of Information and Biological Sciences, Graduate School of Natural Sciences, Nagoya City University, Nagoya, Japan (Matsubara); Laboratory of Animal Cytogenetics & Comparative Genomics, Department of Genetics, Faculty of Science, Kasetsart University, Bangkok, Thailand (Srikulnath); Avian Bioscience Research Center, Graduate School of Bioagricultural Sciences, Nagoya University, Nagoya, Japan (Matsuda); Sydney Medical School QEII Research Institute for Mothers and Infants D02, The University of Sydney , NSW 2006, Australia (Miller); School of Biological Sciences, The University of Sydney, Heydon-Laurence Building A08, NSW 2006, Australia (Olsson); and Department of Biological and Environmental Sciences, University of Gothenburg, Gothenburg, Sweden (Olsson).
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Female heterogamety in Madagascar chameleons (Squamata: Chamaeleonidae: Furcifer): differentiation of sex and neo-sex chromosomes. Sci Rep 2015; 5:13196. [PMID: 26286647 PMCID: PMC4541320 DOI: 10.1038/srep13196] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2015] [Accepted: 07/14/2015] [Indexed: 12/26/2022] Open
Abstract
Amniotes possess variability in sex determining mechanisms, however, this diversity is still only partially known throughout the clade and sex determining systems still remain unknown even in such a popular and distinctive lineage as chameleons (Squamata: Acrodonta: Chamaeleonidae). Here, we present evidence for female heterogamety in this group. The Malagasy giant chameleon (Furcifer oustaleti) (chromosome number 2n = 22) possesses heteromorphic Z and W sex chromosomes with heterochromatic W. The panther chameleon (Furcifer pardalis) (2n = 22 in males, 21 in females), the second most popular chameleon species in the world pet trade, exhibits a rather rare Z1Z1Z2Z2/Z1Z2W system of multiple sex chromosomes, which most likely evolved from W-autosome fusion. Notably, its neo-W chromosome is partially heterochromatic and its female-specific genetic content has expanded into the previously autosomal region. Showing clear evidence for genotypic sex determination in the panther chameleon, we resolve the long-standing question of whether or not environmental sex determination exists in this species. Together with recent findings in other reptile lineages, our work demonstrates that female heterogamety is widespread among amniotes, adding another important piece to the mosaic of knowledge on sex determination in amniotes needed to understand the evolution of this important trait.
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Interstitial Telomeric Motifs in Squamate Reptiles: When the Exceptions Outnumber the Rule. PLoS One 2015; 10:e0134985. [PMID: 26252002 PMCID: PMC4529230 DOI: 10.1371/journal.pone.0134985] [Citation(s) in RCA: 48] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2015] [Accepted: 07/15/2015] [Indexed: 12/19/2022] Open
Abstract
Telomeres are nucleoprotein complexes protecting the physical ends of linear eukaryotic chromosomes and therefore helping to ensure their stability and integrity. Additionally, telomeric sequences can be localized in non-terminal regions of chromosomes, forming so-called interstitial telomeric sequences (ITSs). ITSs are traditionally considered to be relics of chromosomal rearrangements and thus very informative in the reconstruction of the evolutionary history of karyotype formation. We examined the distribution of the telomeric motifs (TTAGGG)n using fluorescence in situ hybridization (FISH) in 30 species, representing 17 families of squamate reptiles, and compared them with the collected data from another 38 species from literature. Out of the 68 squamate species analyzed, 35 possess ITSs in pericentromeric regions, centromeric regions and/or within chromosome arms. We conclude that the occurrence of ITSs is rather common in squamates, despite their generally conserved karyotypes, suggesting frequent and independent cryptic chromosomal rearrangements in this vertebrate group.
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50
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Chassovnikarova T, Rovatsos M, Atanasov N, Koshev Y. Sex chromosome variability of Spermophilus citellus (Linnaeus, 1766) in the Southeastern part of the Balkan Peninsula. Mamm Biol 2015. [DOI: 10.1016/j.mambio.2014.10.002] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
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