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Bouffet-Halle A, Yang W, Gardner MG, Whiting MJ, Wapstra E, Uller T, While GM. Characterisation and cross-amplification of sex-specific genetic markers in Australasian Egerniinae lizards and their implications for understanding the evolution of sex determination and social complexity. AUST J ZOOL 2022. [DOI: 10.1071/zo21023] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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Kostmann A, Augstenová B, Frynta D, Kratochvíl L, Rovatsos M. Cytogenetically Elusive Sex Chromosomes in Scincoidean Lizards. Int J Mol Sci 2021; 22:ijms22168670. [PMID: 34445371 PMCID: PMC8395508 DOI: 10.3390/ijms22168670] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2021] [Revised: 08/08/2021] [Accepted: 08/09/2021] [Indexed: 01/11/2023] Open
Abstract
The lizards of the species-rich clade Scincoidea including cordylids, gerrhosaurids, skinks, and xantusiids, show an almost cosmopolitan geographical distribution and a remarkable ecological and morphological divergence. However, previous studies revealed limited variability in cytogenetic traits. The sex determination mode was revealed only in a handful of gerrhosaurid, skink, and xantusiid species, which demonstrated either ZZ/ZW or XX/XY sex chromosomes. In this study, we explored the karyotypes of six species of skinks, two species of cordylids, and one gerrhosaurid. We applied conventional and molecular cytogenetic methods, including C-banding, fluorescence in situ hybridization with probes specific for telomeric motifs and rDNA loci, and comparative genomic hybridization. The diploid chromosome numbers are rather conserved among these species, but the chromosome morphology, the presence of interstitial telomeric sequences, and the topology of rDNA loci vary significantly. Notably, XX/XY sex chromosomes were identified only in Tiliqua scincoides, where, in contrast to the X chromosome, the Y chromosome lacks accumulations of rDNA loci. We confirm that within the lizards of the scincoidean clade, sex chromosomes remained in a generally poor stage of differentiation.
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Affiliation(s)
- Alexander Kostmann
- Department of Ecology, Faculty of Science, Charles University, 12844 Prague, Czech Republic; (A.K.); (B.A.); (L.K.)
| | - Barbora Augstenová
- Department of Ecology, Faculty of Science, Charles University, 12844 Prague, Czech Republic; (A.K.); (B.A.); (L.K.)
| | - Daniel Frynta
- Department of Zoology, Faculty of Science, Charles University, 12844 Prague, Czech Republic;
| | - Lukáš Kratochvíl
- Department of Ecology, Faculty of Science, Charles University, 12844 Prague, Czech Republic; (A.K.); (B.A.); (L.K.)
| | - Michail Rovatsos
- Department of Ecology, Faculty of Science, Charles University, 12844 Prague, Czech Republic; (A.K.); (B.A.); (L.K.)
- Correspondence:
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Hill P, Shams F, Burridge CP, Wapstra E, Ezaz T. Differences in Homomorphic Sex Chromosomes Are Associated with Population Divergence in Sex Determination in Carinascincus ocellatus (Scincidae: Lygosominae). Cells 2021; 10:291. [PMID: 33535518 PMCID: PMC7912723 DOI: 10.3390/cells10020291] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2020] [Revised: 01/28/2021] [Accepted: 01/28/2021] [Indexed: 01/09/2023] Open
Abstract
Sex determination directs development as male or female in sexually reproducing organisms. Evolutionary transitions in sex determination have occurred frequently, suggesting simple mechanisms behind the transitions, yet their detail remains elusive. Here we explore the links between mechanisms of transitions in sex determination and sex chromosome evolution at both recent and deeper temporal scales (<1 Myr; ~79 Myr). We studied a rare example of a species with intraspecific variation in sex determination, Carinascincus ocellatus, and a relative, Liopholis whitii, using c-banding and mapping of repeat motifs and a custom Y chromosome probe set to identify the sex chromosomes. We identified both unique and conserved regions of the Y chromosome among C. ocellatus populations differing in sex determination. There was no evidence for homology of sex chromosomes between C. ocellatus and L. whitii, suggesting independent evolutionary origins. We discuss sex chromosome homology between members of the subfamily Lygosominae and propose links between sex chromosome evolution, sex determination transitions, and karyotype evolution.
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Affiliation(s)
- Peta Hill
- Discipline of Biological Sciences, University of Tasmania, Private Bag 5, Sandy Bay, TAS 7000, Australia; (C.P.B.); (E.W.)
| | - Foyez Shams
- Institute for Applied Ecology, University of Canberra, Bruce, ACT 2601, Australia; (F.S.); (T.E.)
| | - Christopher P. Burridge
- Discipline of Biological Sciences, University of Tasmania, Private Bag 5, Sandy Bay, TAS 7000, Australia; (C.P.B.); (E.W.)
| | - Erik Wapstra
- Discipline of Biological Sciences, University of Tasmania, Private Bag 5, Sandy Bay, TAS 7000, Australia; (C.P.B.); (E.W.)
| | - Tariq Ezaz
- Institute for Applied Ecology, University of Canberra, Bruce, ACT 2601, Australia; (F.S.); (T.E.)
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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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GARDNER MICHAELG, HUGALL ANDREWF, DONNELLAN STEPHENC, HUTCHINSON MARKN, FOSTER RALPH. Molecular systematics of social skinks: phylogeny and taxonomy of theEgerniagroup (Reptilia: Scincidae). Zool J Linn Soc 2008. [DOI: 10.1111/j.1096-3642.2008.00422.x] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
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CHAPPLE DAVIDG, KEOGH JSCOTT. Parallel adaptive radiations in arid and temperate Australia: molecular phylogeography and systematics of the Egernia whitii (Lacertilia: Scincidae) species group. Biol J Linn Soc Lond 2004. [DOI: 10.1111/j.1095-8312.2004.00378.x] [Citation(s) in RCA: 59] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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Honda M, Ota H, Köhler G, Ineich I, Chirio L, Chen SL, Hikida T. Phylogeny of the lizard subfamily Lygosominae (Reptilia: Scincidae), with special reference to the origin of the new world taxa. Genes Genet Syst 2003; 78:71-80. [PMID: 12655139 DOI: 10.1266/ggs.78.71] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Abstract
Phylogenetic relationships of the three lygosomine skink genera occurring both in the Old World and the New World (Mabuya, Scincella and Sphenomorphus) were inferred from mitochondrial DNA sequence of 12S and 16S rRNA genes. Results strongly suggested the non-monophyly for any of these three genera. Within the Mabuya group, Asian members appear to have diverged first, leaving the Neotropical and the Afro-Malagasy Mabuya as sister groups. These relationships, together with the absence of extant or fossil representatives of the Mabuya group from North America, strongly suggest the trans-Atlantic dispersals of Mabuya from Africa to Neotropics. Our results also indicated a closer affinity of the New World Scincella with the New World Sphenomorphus than with the Old World Scincella. Such relationships suggest the trans-Beringian dispersal of the common ancestor from Asia and its subsequent divergence into the North American Scincella and the Neotropical Sphenomorphus.
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Affiliation(s)
- Masanao Honda
- School of Allied Medical Sciences, Shinshu University, Asahi, Matsumoto, Nagano, Japan.
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Honda M, Ota H, Kobayashi M, Nabhitabhata J, Yong HS, Hikida T. Phylogenetic relationships, character evolution, and biogeography of the subfamily Lygosominae (Reptilia: Scincidae) inferred from mitochondrial DNA sequences. Mol Phylogenet Evol 2000; 15:452-61. [PMID: 10860653 DOI: 10.1006/mpev.1999.0767] [Citation(s) in RCA: 61] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Phylogenetic relationships among the lygosomine skinks were inferred from 1249 base positions of mitochondrial DNA sequences of 12S and 16S rRNA genes. The monophyly of this subfamily was confirmed and the presence of five distinct infrasubfamilial lineages detected. Of these, the Sphenomorphus group appears to have diverged first, followed by the Lygosoma and Egernia groups in order, leaving the Eugongylus and Mabuya groups as sister groups. Our results did not support monophyly of the Mabuya group sensu lato (i.e., an assemblage of the Lygosoma, Egernia, and Mabuya groups), for which a number of morphological and karyological studies demonstrated a considerable similarity. Our results also contradict the previous hypothesis, formulated on the basis of morphological and immunological data, which argued for the sister relationship between the Egernia and the Eugongylus groups. Morphological and karyological characters used to define the Mabuya group (sensu lato) may actually represent plesiomorphic states. The phylogenetic diversity of lygosomine skinks in the Australian region appears to have increased through multiple colonizations from Southeast Asia.
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Affiliation(s)
- M Honda
- Department of Zoology, Graduate School of Science, Kyoto University, Sakyo, Kyoto, 606-8502, Japan.
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Honda M, Ota H, Kobayashi M, Hikida T. Phylogenetic relationships of Australian skinks of the Mabuya group (Reptilia: Scincidae) inferred from mitochondrial DNA sequences. Genes Genet Syst 1999; 74:135-9. [PMID: 10650841 DOI: 10.1266/ggs.74.135] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Abstract
Portions of two mitochondrial genes (12S and 16S ribosomal RNAs) were sequenced to analyze the phylogenetic relationships of the Mabuya group from the Australian region (Corucia, Egernia and Tiliqua). Results indicated the monophyly of these genera and their divergence from Asian and African members of this group. This suggests that the diversity of the Mabuya group in the Australian region has increased through an endemic radiation, not through multiple colonizations from outside. Among the genera from this region, Corucia and Tiliqua were closest to each other. This result contradicts with those of the previous hypotheses on the basis of morphological and immunological data that, respectively, suggested closest affinities between Corucia and Egernia, and Egernia and Tiliqua. We suppose that the morphological characters exclusively joining Corucia and Egernia are actually in plesiomorphic state.
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Affiliation(s)
- M Honda
- Department of Zoology, Graduate School of Science, Kyoto University, Japan
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Chromosomal variation in the scincid genus Mabuya and its arboreal relatives (Reptilia: Squamata). Genetica 1996. [DOI: 10.1007/bf00120222] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
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