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Mezzasalma M. First Cytogenetic Analysis of Hemidactylus mercatorius Gray, 1842 Provides Insights on Interspecific Chromosomal Diversification in the Genus Hemidactylus (Squamata: Gekkonidae). Life (Basel) 2024; 14:181. [PMID: 38398689 PMCID: PMC10890220 DOI: 10.3390/life14020181] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2023] [Revised: 01/18/2024] [Accepted: 01/23/2024] [Indexed: 02/25/2024] Open
Abstract
This contribution provides the first karyotype description of Hemidactylus mercatorius and discusses the interspecific chromosome diversification in the genus. Chromosomal analysis was performed on samples from different Malagasy populations using standard karyotyping, Ag-NOR staining, and banding methods (sequential C-banding + Giemsa, + Chromomycin A3, +4',6-diamidino-2-phenylindole). Irrespective of sex or sampling locality, H. mercatorius shows a karyotype of 2n = 42 with metacentric (1, 18-21), submetacentric (4), subtelocentric (5, 11), and acrocentric pairs (all the remaining pairs). There was no heteromorphic chromosome pair and no clear distinction between macro- and microchromosomes. NORs were localised close to the centromeres of a medium acrocentric pair (14). Heterochromatic blocks were identified on the telomeric and centromeric regions of most chromosome pairs. A comparison with the karyotype of H. mabouia highlights that the different morphology of several chromosome pairs clearly distinguishes the two species, contrasting the previously proposed synonymy. The differences between the karyotypes of H. mercatorius and H. mabouia concern the number of biarmed and acrocentric elements, suggesting the occurrence of several chromosome inversions. Considering all the available karyotype data on Hemidactylus and its sister genus Cyrtodactylus, it is possible to advance an evolutionary hypothesis on their chromosomal evolution, starting from a common ancestor with 2n = 48 and all acrocentric elements. From this ancestral condition, the karyotype diversification in the two genera has been prevalently characterised by a progressive accumulation of fusions and inversions which have reduced the total chromosome count and increased the number of biarmed chromosomes.
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Affiliation(s)
- Marcello Mezzasalma
- Department of Biology, Ecology and Earth Sciences, University of Calabria, Via P. Bucci 4/B, 87036 Rende, Italy
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Mezzasalma M, Brunelli E, Odierna G, Guarino FM. Chromosome Diversity and Evolution of the Endemic Malagasy Velvet Geckos of the Genus Blaesodactylus (Reptilia, Gekkonidae). Animals (Basel) 2023; 13:2068. [PMID: 37443866 DOI: 10.3390/ani13132068] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2023] [Revised: 06/15/2023] [Accepted: 06/20/2023] [Indexed: 07/15/2023] Open
Abstract
We performed a molecular and phylogenetic analysis and a comparative cytogenetic study with standard karyotyping, silver staining (Ag-NOR) and sequential C-banding + Giemsa, + fluorochromes on several Blaesodactylus samples. The phylogenetic inference retrieved two main clades, the first comprises B. victori, B. microtuberculatus and B. boivini, while the second includes B. sakalava, B. antongilensis and B. ambonihazo. The available samples of B. sakalava form two different clades (here named B. sakalava clade A and clade B), which probably deserve a taxonomic re-evaluation. We found a karyological variability in Blaesodactylus in terms of chromosome number (2n = 40-42), morphology, location of NORs, and heterochromatin distribution pattern. Blaesodactylus antongilensis and B. sakalava clade A and B showed a karyotype of 2n = 40 mostly telocentric chromosomes. Pairs 1 and 6 were metacentric in B. sakalava clade A and B, while pair 1 was composed of subtelocentric/submetacentric elements in B. antongilensis. In contrast, B. boivini displayed a karyotype with 2n = 42 only telocentric chromosomes. NORs were on the first chromosome pair in B. boivini, and on the second pair in B. antongilensis. Adding our data to those available from the literature on evolutionarily related species, we highlight that the chromosome diversification in the genus probably proceeded towards a progressive reduction in the chromosome number and the formation of metacentric elements.
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Affiliation(s)
- Marcello Mezzasalma
- Department of Biology, Ecology and Earth Science, University of Calabria, Via P. Bucci 4/B, 87036 Rende, Italy
| | - Elvira Brunelli
- Department of Biology, Ecology and Earth Science, University of Calabria, Via P. Bucci 4/B, 87036 Rende, Italy
| | - Gaetano Odierna
- Department of Biology, University of Naples Federico II, Via Cinthia 26, 80126 Naples, Italy
| | - Fabio Maria Guarino
- Department of Biology, University of Naples Federico II, Via Cinthia 26, 80126 Naples, Italy
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Chrostek G, Domaradzka A, Yurchenko A, Kratochvíl L, Mazzoleni S, Rovatsos M. Cytogenetic Analysis of Seven Species of Gekkonid and Phyllodactylid Geckos. Genes (Basel) 2023; 14:178. [PMID: 36672918 PMCID: PMC9859368 DOI: 10.3390/genes14010178] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [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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Affiliation(s)
| | | | | | | | | | - Michail Rovatsos
- Department of Ecology, Faculty of Science, Charles University, 12844 Prague, Czech Republic
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Pensabene E, Yurchenko A, Kratochvíl L, Rovatsos M. Madagascar Leaf-Tail Geckos ( Uroplatus spp.) Share Independently Evolved Differentiated ZZ/ZW Sex Chromosomes. Cells 2023; 12:260. [PMID: 36672195 PMCID: PMC9856856 DOI: 10.3390/cells12020260] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2022] [Revised: 01/06/2023] [Accepted: 01/07/2023] [Indexed: 01/10/2023] Open
Abstract
Geckos are an excellent group to study the evolution of sex determination, as they possess a remarkable variability ranging from a complete absence of sex chromosomes to highly differentiated sex chromosomes. We explored sex determination in the Madagascar leaf-tail geckos of the genus Uroplatus. The cytogenetic analyses revealed highly heterochromatic W chromosomes in all three examined species (Uroplatus henkeli, U. alluaudi, U. sikorae). The comparative gene coverage analysis between sexes in U. henkeli uncovered an extensive Z-specific region, with a gene content shared with the chicken chromosomes 8, 20, 26 and 28. The genomic region homologous to chicken chromosome 28 has been independently co-opted for the role of sex chromosomes in several vertebrate lineages, including monitors, beaded lizards and monotremes, perhaps because it contains the amh gene, whose homologs were repeatedly recruited as a sex-determining locus. We demonstrate that all tested species of leaf-tail geckos share homologous sex chromosomes despite the differences in shape and size of their W chromosomes, which are not homologous to the sex chromosomes of other closely related genera. The rather old (at least 40 million years), highly differentiated sex chromosomes of Uroplatus geckos can serve as a great system to study the convergence of sex chromosomes evolved from the same genomic region.
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Affiliation(s)
| | | | | | - Michail Rovatsos
- Department of Ecology, Faculty of Science, Charles University, 128 00 Prague, Czech Republic
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Singchat W, Panthum T, Ahmad SF, Baicharoen S, Muangmai N, Duengkae P, Griffin DK, Srikulnath K. Remnant of Unrelated Amniote Sex Chromosomal Linkage Sharing on the Same Chromosome in House Gecko Lizards, Providing a Better Understanding of the Ancestral Super-Sex Chromosome. Cells 2021; 10:cells10112969. [PMID: 34831192 PMCID: PMC8616239 DOI: 10.3390/cells10112969] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2021] [Accepted: 10/28/2021] [Indexed: 12/18/2022] Open
Abstract
Comparative chromosome maps investigating sex chromosomal linkage groups in amniotes and microsatellite repeat motifs of a male house gecko lizard (Hemidactylus frenatus, HFR) and a flat-tailed house gecko lizard (H. platyurus, HPL) of unknown sex were examined using 75 bacterial artificial chromosomes (BACs) from chicken and zebra finch genomes. No massive accumulations of microsatellite repeat motifs were found in either of the gecko lizards, but 10 out of 13 BACs mapped on HPL chromosomes were associated with other amniote sex chromosomes. Hybridization of the same BACs onto multiple different chromosome pairs suggested transitions to sex chromosomes across amniotes. No BAC hybridization signals were found on HFR chromosomes. However, HFR diverged from HPL about 30 million years ago, possibly due to intrachromosomal rearrangements occurring in the HFR lineage. By contrast, heterochromatin likely reshuffled patterns between HPL and HFR, as observed from C-positive heterochromatin distribution. Six out of ten BACs showed partial homology with squamate reptile chromosome 2 (SR2) and snake Z and/or W sex chromosomes. The gecko lizard showed shared unrelated sex chromosomal linkages-the remnants of a super-sex chromosome. A large ancestral super-sex chromosome showed a correlation between SR2 and snake W sex chromosomes.
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Affiliation(s)
- Worapong Singchat
- Animal Genomics and Bioresource Research Center (AGB Research Center), Faculty of Science, Kasetsart University, 50 Ngamwongwan, Chatuchak, Bangkok 10900, Thailand; (W.S.); (T.P.); (S.F.A.)
- Laboratory of Animal Cytogenetics and Comparative Genomics (ACCG), Department of Genetics, Faculty of Science, Kasetsart University, 50 Ngamwongwan, Chatuchak, Bangkok 10900, Thailand
- Special Research Unit for Wildlife Genomics (SRUWG), Department of Forest Biology, Faculty of Forestry, Kasetsart University, 50 Ngamwongwan, Chatuchak, Bangkok 10900, Thailand;
| | - Thitipong Panthum
- Animal Genomics and Bioresource Research Center (AGB Research Center), Faculty of Science, Kasetsart University, 50 Ngamwongwan, Chatuchak, Bangkok 10900, Thailand; (W.S.); (T.P.); (S.F.A.)
- Laboratory of Animal Cytogenetics and Comparative Genomics (ACCG), Department of Genetics, Faculty of Science, Kasetsart University, 50 Ngamwongwan, Chatuchak, Bangkok 10900, Thailand
- Special Research Unit for Wildlife Genomics (SRUWG), Department of Forest Biology, Faculty of Forestry, Kasetsart University, 50 Ngamwongwan, Chatuchak, Bangkok 10900, Thailand;
| | - Syed Farhan Ahmad
- Animal Genomics and Bioresource Research Center (AGB Research Center), Faculty of Science, Kasetsart University, 50 Ngamwongwan, Chatuchak, Bangkok 10900, Thailand; (W.S.); (T.P.); (S.F.A.)
- Laboratory of Animal Cytogenetics and Comparative Genomics (ACCG), Department of Genetics, Faculty of Science, Kasetsart University, 50 Ngamwongwan, Chatuchak, Bangkok 10900, Thailand
- Special Research Unit for Wildlife Genomics (SRUWG), Department of Forest Biology, Faculty of Forestry, Kasetsart University, 50 Ngamwongwan, Chatuchak, Bangkok 10900, Thailand;
| | - Sudarath Baicharoen
- Bureau of Conservation and Research, Zoological Park Organization of Thailand, Bangkok 10300, Thailand;
| | - Narongrit Muangmai
- Department of Fishery Biology, Faculty of Fisheries, Kasetsart University, 50 Ngamwongwan, Chatuchak, Bangkok 10900, Thailand;
| | - Prateep Duengkae
- Special Research Unit for Wildlife Genomics (SRUWG), Department of Forest Biology, Faculty of Forestry, Kasetsart University, 50 Ngamwongwan, Chatuchak, Bangkok 10900, Thailand;
| | | | - Kornsorn Srikulnath
- Animal Genomics and Bioresource Research Center (AGB Research Center), Faculty of Science, Kasetsart University, 50 Ngamwongwan, Chatuchak, Bangkok 10900, Thailand; (W.S.); (T.P.); (S.F.A.)
- Laboratory of Animal Cytogenetics and Comparative Genomics (ACCG), Department of Genetics, Faculty of Science, Kasetsart University, 50 Ngamwongwan, Chatuchak, Bangkok 10900, Thailand
- Special Research Unit for Wildlife Genomics (SRUWG), Department of Forest Biology, Faculty of Forestry, Kasetsart University, 50 Ngamwongwan, Chatuchak, Bangkok 10900, Thailand;
- Amphibian Research Center, Hiroshima University, 1-3-1 Kagamiyama, Higashihiroshima 739-8526, Japan
- Correspondence:
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Mezzasalma M, Guarino FM, Odierna G. Lizards as Model Organisms of Sex Chromosome Evolution: What We Really Know from a Systematic Distribution of Available Data? Genes (Basel) 2021; 12:1341. [PMID: 34573323 PMCID: PMC8468487 DOI: 10.3390/genes12091341] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2021] [Revised: 08/20/2021] [Accepted: 08/27/2021] [Indexed: 01/19/2023] Open
Abstract
Lizards represent unique model organisms in the study of sex determination and sex chromosome evolution. Among tetrapods, they are characterized by an unparalleled diversity of sex determination systems, including temperature-dependent sex determination (TSD) and genetic sex determination (GSD) under either male or female heterogamety. Sex chromosome systems are also extremely variable in lizards. They include simple (XY and ZW) and multiple (X1X2Y and Z1Z2W) sex chromosome systems and encompass all the different hypothesized stages of diversification of heterogametic chromosomes, from homomorphic to heteromorphic and completely heterochromatic sex chromosomes. The co-occurrence of TSD, GSD and different sex chromosome systems also characterizes different lizard taxa, which represent ideal models to study the emergence and the evolutionary drivers of sex reversal and sex chromosome turnover. In this review, we present a synthesis of general genome and karyotype features of non-snakes squamates and discuss the main theories and evidences on the evolution and diversification of their different sex determination and sex chromosome systems. We here provide a systematic assessment of the available data on lizard sex chromosome systems and an overview of the main cytogenetic and molecular methods used for their identification, using a qualitative and quantitative approach.
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Affiliation(s)
- Marcello Mezzasalma
- Department of Biology, University of Naples Federico II, I-80126 Naples, Italy; (F.M.G.); (G.O.)
- CIBIO-InBIO, Centro de Investigação em Biodiversidade e Recursos Genéticos, InBIO, Universidade do Porto, Rua Padre Armando Quintas 7, 4485-661 Vairaõ, Portugal
| | - Fabio M. Guarino
- Department of Biology, University of Naples Federico II, I-80126 Naples, Italy; (F.M.G.); (G.O.)
| | - Gaetano Odierna
- Department of Biology, University of Naples Federico II, I-80126 Naples, Italy; (F.M.G.); (G.O.)
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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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Thongnetr W, Aiumsumang S, Kongkaew R, Tanomtong A, Suwannapoom C, Phimphan S. Cytogenetic characterisation and chromosomal mapping of microsatellite and telomeric repeats in two gecko species (Reptilia, Gekkonidae) from Thailand. COMPARATIVE CYTOGENETICS 2021; 15:41-52. [PMID: 33603980 PMCID: PMC7873012 DOI: 10.3897/compcytogen.v15i1.58208] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 09/01/2020] [Accepted: 12/16/2020] [Indexed: 06/12/2023]
Abstract
Studies of chromosomes of Cyrtodactylus jarujini Ulber, 1993 and C. doisuthep Kunya et al., 2014 to compare microsatellite and TTAGGG sequences by classical and molecular techniques were conducted in Thailand. Karyological typing from a conventional staining technique of C. jarujini and C. doisuthep showed diploid chromosome numbers of 40 and 34 while the Fundamental Numbers (NF) were 56 in both species. In addition, we created the chromosome formula of the chromosomes of C. jarujini showing that 2n (40) = Lsm 1 + Lsm 2 + Lt 3 + Mm 1 + Mt 4 + Sm 2 + Sa 2 + St 5 while that of C. doisuthep was 2n (34) = Lsm 3 + Lm 2 + Lt 3 + Mm 1 + Mt 2 + Sm 4 + Sa 1 + St 1. Ag-NOR staining revealed NOR-bearing chromosomes in chromosome pairs 13 and 14 in C. jarujini, and in chromosome pairs 9 and 13 in C. doisuthep. This molecular study used the FISH technique, as well as microsatellite probes including (A)20, (TA)15, (CGG)10, (CGG)10, (GAA)10, (TA)15 and TTAGGG repeats. The signals showed that the different patterns in each chromosome of the Gekkonids depended on probe types. TTAGGG repeats showed high distribution on centromere and telomere regions, while (A)20, (TA)15, (CGG)10, (CGG)10, (GAA)10 and (TA)15 bearing dispersed over the whole genomes including chromosomes and some had strong signals on only a pair of homologous chromosomes. These results suggest that the genetic linkages have been highly differentiated between the two species.
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Affiliation(s)
- Weera Thongnetr
- Walai Rukhavej Botanical Research institute, Mahasarakham University, Kantharawichai, Maha Sarakham, ThailandMahasarakham UniversityMaha SarakhamThailand
| | - Surachest Aiumsumang
- Biology program, Faculty of Science and Technology, Phetchabun Rajabhat University, Phetchabun, 67000, ThailandPhetchabun Rajabhat UniversityPhetchabunThailand
| | - Rodjarin Kongkaew
- Program of Biology, Faculty of Science, Khon Kaen University, Muang, Khon Kaen, 40002, ThailandKhon Kaen UniversityKhon KaenThailand
| | - Alongklod Tanomtong
- Program of Biology, Faculty of Science, Khon Kaen University, Muang, Khon Kaen, 40002, ThailandKhon Kaen UniversityKhon KaenThailand
| | - Chatmongkon Suwannapoom
- Department of Fishery, School of Agriculture and Natural Resources, University of Phayao, Muang, Phayao, 56000, ThailandUniversity of PhayaoPhayaoThailand
| | - Sumalee Phimphan
- Biology program, Faculty of Science and Technology, Phetchabun Rajabhat University, Phetchabun, 67000, ThailandPhetchabun Rajabhat UniversityPhetchabunThailand
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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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10
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Distribution and amplification of interstitial telomeric sequences (ITSs) in Australian dragon lizards support frequent chromosome fusions in Iguania. PLoS One 2019; 14:e0212683. [PMID: 30794668 PMCID: PMC6386254 DOI: 10.1371/journal.pone.0212683] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2018] [Accepted: 02/07/2019] [Indexed: 11/19/2022] Open
Abstract
Telomeric sequences are generally located at the ends of chromosomes; however, they can also be found in non-terminal chromosomal regions when they are known as interstitial telomeric sequences (ITSs). Distribution of ITSs across closely related and divergent species elucidates karyotype evolution and speciation as ITSs provide evolutionary evidence for chromosome fusion. In this study, we performed physical mapping of telomeric repeats by fluorescence in situ hybridisation (FISH) in seven Australian dragon lizards thought to represent derived karyotypes of squamate reptiles and a gecko lizard with considerably different karyotypic feature. Telomeric repeats were present at both ends of all chromosomes in all species, while varying numbers of ITSs were also found on microchromosomes and in pericentromeric or centromeric regions on macrochromosomes in five lizard species examined. This suggests that chromosomal rearrangements from ancestral squamate reptiles to Iguania occurred mainly by fusion between ancestral types of acrocentric chromosomes and/or between microchromosomes, leading to appearance of bi-armed macrochromosomes, and in the reduction of microchromosome numbers. These results support the previously proposed hypothesis of karyotype evolution in squamate reptiles. In addition, we observed the presence of telomeric sequences in the similar regions to heterochromatin of the W microchromosome in Pogona barbata and Doporiphora nobbi, while sex chromosomes for the two species contained part of the nucleolar organiser regions (NORs). This likely implies that these ITSs are a part of the satellite DNA and not relics of chromosome fusions. Amplification of telomeric repeats may have involved heterochromatinisation of sex-specific W chromosomes and play a role in the organisation of the nucleolus.
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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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12
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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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Deakin JE, Edwards MJ, Patel H, O'Meally D, Lian J, Stenhouse R, Ryan S, Livernois AM, Azad B, Holleley CE, Li Q, Georges A. Anchoring genome sequence to chromosomes of the central bearded dragon (Pogona vitticeps) enables reconstruction of ancestral squamate macrochromosomes and identifies sequence content of the Z chromosome. BMC Genomics 2016; 17:447. [PMID: 27286959 PMCID: PMC4902969 DOI: 10.1186/s12864-016-2774-3] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2016] [Accepted: 05/25/2016] [Indexed: 12/30/2022] Open
Abstract
Background Squamates (lizards and snakes) are a speciose lineage of reptiles displaying considerable karyotypic diversity, particularly among lizards. Understanding the evolution of this diversity requires comparison of genome organisation between species. Although the genomes of several squamate species have now been sequenced, only the green anole lizard has any sequence anchored to chromosomes. There is only limited gene mapping data available for five other squamates. This makes it difficult to reconstruct the events that have led to extant squamate karyotypic diversity. The purpose of this study was to anchor the recently sequenced central bearded dragon (Pogona vitticeps) genome to chromosomes to trace the evolution of squamate chromosomes. Assigning sequence to sex chromosomes was of particular interest for identifying candidate sex determining genes. Results By using two different approaches to map conserved blocks of genes, we were able to anchor approximately 42 % of the dragon genome sequence to chromosomes. We constructed detailed comparative maps between dragon, anole and chicken genomes, and where possible, made broader comparisons across Squamata using cytogenetic mapping information for five other species. We show that squamate macrochromosomes are relatively well conserved between species, supporting findings from previous molecular cytogenetic studies. Macrochromosome diversity between members of the Toxicofera clade has been generated by intrachromosomal, and a small number of interchromosomal, rearrangements. We reconstructed the ancestral squamate macrochromosomes by drawing upon comparative cytogenetic mapping data from seven squamate species and propose the events leading to the arrangements observed in representative species. In addition, we assigned over 8 Mbp of sequence containing 219 genes to the Z chromosome, providing a list of genes to begin testing as candidate sex determining genes. Conclusions Anchoring of the dragon genome has provided substantial insight into the evolution of squamate genomes, enabling us to reconstruct ancestral macrochromosome arrangements at key positions in the squamate phylogeny, demonstrating that fusions between macrochromosomes or fusions of macrochromosomes and microchromosomes, have played an important role during the evolution of squamate genomes. Assigning sequence to the sex chromosomes has identified NR5A1 as a promising candidate sex determining gene in the dragon. Electronic supplementary material The online version of this article (doi:10.1186/s12864-016-2774-3) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Janine E Deakin
- Institute for Applied Ecology, University of Canberra, Canberra, ACT 2601, Australia.
| | - Melanie J Edwards
- Institute for Applied Ecology, University of Canberra, Canberra, ACT 2601, Australia
| | - Hardip Patel
- John Curtin School of Medical Research, Australian National University, Canberra, ACT 2601, Australia
| | - Denis O'Meally
- Institute for Applied Ecology, University of Canberra, Canberra, ACT 2601, Australia
| | - Jinmin Lian
- China National GeneBank, BGI-Shenzhen, Shenzhen, 518083, China
| | - Rachael Stenhouse
- Institute for Applied Ecology, University of Canberra, Canberra, ACT 2601, Australia
| | - Sam Ryan
- Institute for Applied Ecology, University of Canberra, Canberra, ACT 2601, Australia
| | - Alexandra M Livernois
- Institute for Applied Ecology, University of Canberra, Canberra, ACT 2601, Australia
| | - Bhumika Azad
- Institute for Applied Ecology, University of Canberra, Canberra, ACT 2601, Australia.,John Curtin School of Medical Research, Australian National University, Canberra, ACT 2601, Australia
| | - Clare E Holleley
- Institute for Applied Ecology, University of Canberra, Canberra, ACT 2601, Australia
| | - Qiye Li
- China National GeneBank, BGI-Shenzhen, Shenzhen, 518083, China.,Centre for GeoGenetics, Natural History Museum of Denmark, University of Copenhagen, Øster Voldgade 5-7, Copenhagen, 1350, Denmark
| | - Arthur Georges
- Institute for Applied Ecology, University of Canberra, Canberra, ACT 2601, Australia
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14
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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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15
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Srikulnath K, Uno Y, Nishida C, Ota H, Matsuda Y. Karyotype Reorganization in the Hokou Gecko (Gekko hokouensis, Gekkonidae): The Process of Microchromosome Disappearance in Gekkota. PLoS One 2015; 10:e0134829. [PMID: 26241471 PMCID: PMC4524605 DOI: 10.1371/journal.pone.0134829] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2015] [Accepted: 07/15/2015] [Indexed: 01/12/2023] Open
Abstract
The Hokou gecko (Gekko hokouensis: Gekkonidae, Gekkota, Squamata) has the chromosome number 2n = 38, with no microchromosomes. For molecular cytogenetic characterization of the gekkotan karyotype, we constructed a cytogenetic map for G. hokouensis, which retains the ancestral karyotype of Gekkota, with 86 functional genes, and compared it with cytogenetic maps for four Toxicofera species that have many microchromosomes (Elaphe quadrivirgata, Varanus salvator macromaculatus, Leiolepis reevesii rubritaeniata, and Anolis carolinensis) and that for a lacertid species (Lacerta agilis) with only one pair of autosomal microchromosomes. Ten pairs of G. hokouensis chromosomes [GHO1, 2, 3, Z(4), 6, 7, 8, 13, 14, and 15] showed highly conserved linkage homology with macrochromosomes and/or macrochromosome arms of the four Toxicofera species and corresponded to eight L. agilis macrochromosomes (LAG). However, GHO5, GHO9, GHO10, GHO11, and LAG6 were composed of chromosome segments that have a homology with Toxicofera microchromosomes, and no homology was found in the chromosomes between G. hokouensis and L. agilis. These results suggest that repeated fusions of microchromosomes may have occurred independently in each lineage of Gekkota and Lacertidae, leading to the disappearance of microchromosomes and appearance of small-sized macrochromosomes.
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Affiliation(s)
- Kornsorn Srikulnath
- Laboratory of Animal Genetics, Department of Applied Molecular Biosciences, Graduate School of Bioagricultural Sciences, Nagoya University, Furo-cho, Chikusa-ku, Nagoya, Aichi, Japan
- Laboratory of Animal Cytogenetics and Comparative Genomics, Department of Genetics, Faculty of Science, Kasetsart University, 50 Ngamwongwan, Chatuchak, Bangkok, Thailand
- Center for Advanced Studies in Tropical Natural Resources, National Research University-Kasetsart University (CASTNAR, NRU-KU), Kasetsart University, Bangkok, Thailand
| | - Yoshinobu Uno
- Laboratory of Animal Genetics, Department of Applied Molecular Biosciences, Graduate School of Bioagricultural Sciences, Nagoya University, Furo-cho, Chikusa-ku, Nagoya, Aichi, Japan
| | - Chizuko Nishida
- Department of Natural History Sciences, Faculty of Science, Hokkaido University, Kita 10, Nishi 8, Kita-ku, Sapporo, Hokkaido, Japan
| | - Hidetoshi Ota
- Institute of Natural and Environmental Sciences, University of Hyogo, and Museum of Nature and Human Activities, Sanda, Hyogo, Japan
| | - Yoichi Matsuda
- Laboratory of Animal Genetics, Department of Applied Molecular Biosciences, Graduate School of Bioagricultural Sciences, Nagoya University, Furo-cho, Chikusa-ku, Nagoya, Aichi, Japan
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16
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Trifonov VA, Paoletti A, Caputo Barucchi V, Kalinina T, O’Brien PCM, Ferguson-Smith MA, Giovannotti M. Comparative Chromosome Painting and NOR Distribution Suggest a Complex Hybrid Origin of Triploid Lepidodactylus lugubris (Gekkonidae). PLoS One 2015; 10:e0132380. [PMID: 26148117 PMCID: PMC4492922 DOI: 10.1371/journal.pone.0132380] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2014] [Accepted: 06/13/2015] [Indexed: 11/24/2022] Open
Abstract
Parthenogenesis, unisexuality and triploidy are interesting but poorly studied phenomena occurring in some reptile species. The mourning gecko (Lepidodactylus lugubris) represents a complex of diploid and triploid parthenogenetic mostly all-female populations (males occur quite rarely) widely distributed in coastal areas of the Indian and Pacific Oceans. Here, we study karyotypes of a male and two female L. lugubris (LLU) triploid individuals (3n = 66) using comparative painting with Gekko japonicus, Hemidactylus turcicus and H. platyurus chromosome specific probes to visualize the homologous regions and to reveal genus specific rearrangements. Also, we applied a 28S ribosomal DNA probe and Ag-staining to detect nucleolus organizer regions (NORs). Our results suggest that the karyotype of L. lugubris underwent a chromosome fission and a fusion after its divergence from a common ancestor of the Gekko-Hemidactylus group. The NORs were found to be located on one out of three homologs on each of LLU8, LLU15 and LLU18, thus further confirming a hybrid origin of triploid individuals. It seems that three different bisexual populations might have contributed to the origin of this triploid parthenogenetic population. We postulate that the heterozygosity in NOR localization is maintained in the triploid clone studied by the absence of recombination as described in whiptail lizards. The pattern of NOR localizations and homologous regions in males and females, as well as the absence of other detectable karyotypic differences, suggest that males arise spontaneously in all female populations and do not arise from independent hybridizations with different species.
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Affiliation(s)
- Vladimir A. Trifonov
- Institute of Molecular and Cellular Biology SB RAS, Novosibirsk, Russia
- Novosibirsk State University, Novosibirsk, Russia
- * E-mail:
| | - Alessio Paoletti
- Dipartimento di Scienze della Vita e dell’Ambiente, Università Politecnica delle Marche, Ancona, Italy
| | - Vincenzo Caputo Barucchi
- Dipartimento di Scienze della Vita e dell’Ambiente, Università Politecnica delle Marche, Ancona, Italy
- Consiglio Nazionale delle Ricerche, Istituto di Scienze Marine Sezione Pesca Marittima,Ancona, Italy
| | - Tatiana Kalinina
- Institute of Molecular and Cellular Biology SB RAS, Novosibirsk, Russia
- Novosibirsk State University, Novosibirsk, Russia
| | - Patricia C. M. O’Brien
- Cambridge Resource Centre for Comparative Genomics, University of Cambridge, Cambridge, United Kingdom
| | - Malcolm A. Ferguson-Smith
- Cambridge Resource Centre for Comparative Genomics, University of Cambridge, Cambridge, United Kingdom
| | - Massimo Giovannotti
- Dipartimento di Scienze della Vita e dell’Ambiente, Università Politecnica delle Marche, Ancona, Italy
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Johnson Pokorná M, Trifonov VA, Rens W, Ferguson-Smith MA, Kratochvíl L. Low rate of interchromosomal rearrangements during old radiation of gekkotan lizards (Squamata: Gekkota). Chromosome Res 2015; 23:299-309. [PMID: 25665924 DOI: 10.1007/s10577-015-9468-6] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2014] [Revised: 01/20/2015] [Accepted: 01/21/2015] [Indexed: 01/21/2023]
Abstract
Gekkotan lizards are a highly specious (∼1600 described species) clade of squamate lizards with nearly cosmopolitan distribution in warmer areas. The clade is primarily nocturnal and forms an ecologically dominant part of the world nocturnal herpetofauna. However, molecular cytogenetic methods to study the evolution of karyotypes have not been widely applied in geckos. Our aim here was to uncover the extent of chromosomal rearrangements across the whole group Gekkota and to search for putative synapomorphies supporting the newly proposed phylogenetic relationships within this clade. We applied cross-species chromosome painting with the recently derived whole-chromosomal probes from the gekkonid species Gekko japonicus to members of the major gekkotan lineages. We included members of the families Diplodactylidae, Carphodactylidae, Pygopodidae, Eublepharidae, Phyllodactylidae and Gekkonidae. Our study demonstrates relatively high chromosome conservatism across the ancient group of gekkotan lizards. We documented that many changes in chromosomal shape across geckos can be attributed to intrachromosomal rearrangements. The documented rearrangements are not totally in agreement with the recently newly erected family Phyllodactylidae. The results also pointed to homoplasy, particularly in the reuse of chromosome breakpoints, in the evolution of gecko karyotypes.
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Affiliation(s)
- Martina Johnson Pokorná
- Department of Ecology, Faculty of Science, Charles University in Prague, Viničná 7, Praha 2, Czech Republic
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18
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Cocca E, Petraccioli A, Morescalchi MA, Odierna G, Capriglione T. Laser microdissection-based analysis of the Y sex chromosome of the Antarctic fish Chionodracohamatus (Notothenioidei, Channichthyidae). COMPARATIVE CYTOGENETICS 2015; 9:1-15. [PMID: 25893071 PMCID: PMC4387377 DOI: 10.3897/compcytogen.v9i1.8731] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/10/2014] [Accepted: 12/09/2014] [Indexed: 05/16/2023]
Abstract
Microdissection, DOP-PCR amplification and microcloning were used to study the large Y chromosome of Chionodracohamatus, an Antarctic fish belonging to the Notothenioidei, the dominant component of the Southern Ocean fauna. The species has evolved a multiple sex chromosome system with digametic males showing an X1YX2 karyotype and females an X1X1X2X2 karyotype. Fluorescence in situ hybridization, performed with a painting probe made from microdissected Y chromosomes, allowed a deeper insight on the chromosomal rearrangement, which underpinned the fusion event that generated the Y. Then, we used a DNA library established by microdissection and microcloning of the whole Y chromosome of Chionodracohamatus for searching sex-linked sequences. One clone provided preliminary information on the presence on the Y chromosome of the CHD1 gene homologue, which is sex-linked in birds but in no other vertebrates. Several clones from the Y-chromosome mini-library contained microsatellites and transposable elements, one of which mapped to the q arm putative fusion region of the Y chromosome. The findings confirm that interspersed repetitive sequences might have fostered chromosome rearrangements and the emergence of the Y chromosome in Chionodracohamatus. Detection of the CHD1 gene in the Y sex-determining region could be a classical example of convergent evolution in action.
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Affiliation(s)
- Ennio Cocca
- Istituto di Bioscienze e Biorisorse, CNR, via P. Castellino 111, 80131 Napoli, Italy
| | - Agnese Petraccioli
- Dipartimento di Biologia, Università di Napoli Federico II, Complesso Universitario Monte S. Angelo, via Cinthia, 80126 Napoli, Italy
| | | | - Gaetano Odierna
- Dipartimento di Biologia, Università di Napoli Federico II, Complesso Universitario Monte S. Angelo, via Cinthia, 80126 Napoli, Italy
| | - Teresa Capriglione
- Dipartimento di Biologia, Università di Napoli Federico II, Complesso Universitario Monte S. Angelo, via Cinthia, 80126 Napoli, Italy
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Gamble T, Coryell J, Ezaz T, Lynch J, Scantlebury DP, Zarkower D. Restriction Site-Associated DNA Sequencing (RAD-seq) Reveals an Extraordinary Number of Transitions among Gecko Sex-Determining Systems. Mol Biol Evol 2015; 32:1296-309. [DOI: 10.1093/molbev/msv023] [Citation(s) in RCA: 182] [Impact Index Per Article: 20.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023] Open
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20
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Schmid M, Steinlein C, Feichtinger W, Haaf T, Mijares-Urrutia A, Schargel WE, Hedges SB. Cytogenetic Studies on Gonatodes (Reptilia, Squamata, Sphaerodactylidae). Cytogenet Genome Res 2014; 144:47-61. [DOI: 10.1159/000367929] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/09/2014] [Indexed: 11/19/2022] Open
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21
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Matsubara K, Gamble T, Matsuda Y, Zarkower D, Sarre SD, Georges A, Graves JAM, Ezaz T. Non-homologous sex chromosomes in two geckos (Gekkonidae: Gekkota) with female heterogamety. Cytogenet Genome Res 2014; 143:251-8. [PMID: 25227445 DOI: 10.1159/000366172] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/07/2014] [Indexed: 11/19/2022] Open
Abstract
Evaluating homology between the sex chromosomes of different species is an important first step in deducing the origins and evolution of sex-determining mechanisms in a clade. Here, we describe the preparation of Z and W chromosome paints via chromosome microdissection from the Australian marbled gecko (Christinus marmoratus) and their subsequent use in evaluating sex chromosome homology with the ZW chromosomes of the Kwangsi gecko (Gekko hokouensis) from eastern Asia. We show that the ZW sex chromosomes of C. marmoratus and G. hokouensis are not homologous and represent independent origins of female heterogamety within the Gekkonidae. We also show that the C. marmoratus Z and W chromosomes are genetically similar to each other as revealed by C-banding, comparative genomic hybridization, and the reciprocal painting of Z and W chromosome probes. This implies that sex chromosomes in C. marmoratus are at an early stage of differentiation, suggesting a recent origin.
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Affiliation(s)
- Kazumi Matsubara
- Institute for Applied Ecology, University of Canberra, Canberra, A.C.T., Australia
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22
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Deakin JE, Ezaz T. Tracing the evolution of amniote chromosomes. Chromosoma 2014; 123:201-16. [PMID: 24664317 PMCID: PMC4031395 DOI: 10.1007/s00412-014-0456-y] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2013] [Revised: 03/03/2014] [Accepted: 03/04/2014] [Indexed: 01/09/2023]
Abstract
A great deal of diversity in chromosome number and arrangement is observed across the amniote phylogeny. Understanding how this diversity is generated is important for determining the role of chromosomal rearrangements in generating phenotypic variation and speciation. Gaining this understanding is achieved by reconstructing the ancestral genome arrangement based on comparisons of genome organization of extant species. Ancestral karyotypes for several amniote lineages have been reconstructed, mainly from cross-species chromosome painting data. The availability of anchored whole genome sequences for amniote species has increased the evolutionary depth and confidence of ancestral reconstructions from those made solely from chromosome painting data. Nonetheless, there are still several key lineages where the appropriate data required for ancestral reconstructions is lacking. This review highlights the progress that has been made towards understanding the chromosomal changes that have occurred during amniote evolution and the reconstruction of ancestral karyotypes.
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Affiliation(s)
- Janine E Deakin
- Institute for Applied Ecology, University of Canberra, Canberra, 2601, Australia,
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23
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Ishijima J, Uno Y, Nishida C, Matsuda Y. Genomic structures of the kW1 loci on the Z and W chromosomes in ratite birds: structural changes at an early stage of W chromosome differentiation. Cytogenet Genome Res 2014; 142:255-67. [PMID: 24820528 DOI: 10.1159/000362479] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 02/24/2014] [Indexed: 11/19/2022] Open
Abstract
The W chromosome of ratite birds shows minimal morphological differentiation and retains homology of genetic linkage and gene order with a substantial stretch of the Z chromosome; however, the molecular structure in the differentiated region is still not well known. The kW1 sequence was isolated from the kiwi as a W-specific DNA marker for PCR-based molecular sexing of ratite birds. In ratite W chromosomes, this sequence commonly contains a ∼200-bp deletion. To characterize the very early event of avian sex chromosome differentiation, we performed molecular cytogenetic analyses of kW1 and its flanking sequences in paleognathous and neognathous birds and reptiles. Female-specific repeats were found in the kW1-flanking sequence of the cassowary (Casuarius casuarius), and the repeats have been amplified in the pericentromeric region of the W chromosomes of ratites, which may have resulted from the cessation of meiotic recombination between the Z and W chromosomes at an early stage of sex chromosome differentiation. The presence of the kW1 sequence in neognathous birds and a crocodilian species suggests that the kW1 sequence was present in the ancestral genome of Archosauria; however, it disappeared in other reptilian taxa and several lineages of neognathous birds.
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Affiliation(s)
- Junko Ishijima
- Laboratory of Animal Cytogenetics, Department of Biological Sciences, Graduate School of Science, Hokkaido University, Sapporo, Japan
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24
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Abstract
Fluorescent in situ hybridization (FISH) of whole arm chromosome probes is a robust technique for mapping genomic regions of interest, detecting chromosomal rearrangements, and studying three-dimensional (3D) organization of chromosomes in the cell nucleus. The advent of laser capture microdissection (LCM) and whole genome amplification (WGA) allows obtaining large quantities of DNA from single cells. The increased sensitivity of WGA kits prompted us to develop chromosome paints and to use them for exploring chromosome organization and evolution in non-model organisms. Here, we present a simple method for isolating and amplifying the euchromatic segments of single polytene chromosome arms from ovarian nurse cells of the African malaria mosquito Anopheles gambiae. This procedure provides an efficient platform for obtaining chromosome paints, while reducing the overall risk of introducing foreign DNA to the sample. The use of WGA allows for several rounds of re-amplification, resulting in high quantities of DNA that can be utilized for multiple experiments, including 2D and 3D FISH. We demonstrated that the developed chromosome paints can be successfully used to establish the correspondence between euchromatic portions of polytene and mitotic chromosome arms in An. gambiae. Overall, the union of LCM and single-chromosome WGA provides an efficient tool for creating significant amounts of target DNA for future cytogenetic and genomic studies.
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Patawang I, Tanomtong A, Jumrusthanasan S, Kakampuy W, Neeratanaphan L, Pinthong K. Chromosomal Characteristics of NORs and Karyological Analysis of Tokay Gecko, Gekko gecko (Gekkonidae, Squamata) from Mitotic and Meiotic Cell Division. CYTOLOGIA 2014. [DOI: 10.1508/cytologia.79.315] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Affiliation(s)
- Isara Patawang
- Applied Taxonomic Research Center (ATRC), Department of Biology, Faculty of Science, Khon Kaen University
| | - Alongklod Tanomtong
- Applied Taxonomic Research Center (ATRC), Department of Biology, Faculty of Science, Khon Kaen University
| | - Sarun Jumrusthanasan
- Applied Taxonomic Research Center (ATRC), Department of Biology, Faculty of Science, Khon Kaen University
| | - Wanpen Kakampuy
- Faculty of Agriculture and Technology, Nakhon Phanom University
| | | | - Krit Pinthong
- Department of Fundamental Science, Faculty of Science and Technology, Surindra Rajabhat University
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Gornung E, Mosconi F, Annesi F, Castiglia R. The first cytogenetic description of Euleptes europaea (Gené, 1839) from Northern Sardinia reveals the highest diploid chromosome number among sphaerodactylid geckos (Sphaerodactylidae, Squamata). COMPARATIVE CYTOGENETICS 2013; 7:153-161. [PMID: 24260697 PMCID: PMC3833756 DOI: 10.3897/compcytogen.v7i2.4881] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 02/19/2013] [Accepted: 05/27/2013] [Indexed: 06/02/2023]
Abstract
The karyotype of a sphaerodactylid gecko Euleptes europaea (Gené, 1839) was assembled for the first time in this species. It is made of 2n = 42 gradually decreasing in size chromosomes, the highest chromosome number so far acknowledged in the family Sphaerodactylidae. The second chromosome pair of the karyotype appears slightly heteromorphic in the male individual. Accordingly, FISH with a telomeric probe revealed an uneven distribution of telomeric repeats on the two homologues of this pair, which may be indicative of an XY sex-determination system in the species, to be further investigated.
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Affiliation(s)
- Ekaterina Gornung
- Dipartimento di Biologia e Biotecnologie “Charles Darwin”, Università di Roma “La Sapienza”, Via Alfonso Borelli 50 – 00161 – Roma – Italia
| | - Fabio Mosconi
- Cooperativa Myosotis c/o Museo Civico di Zoologia di Roma, Via Aldrovandi 18 – 00197 – Roma – Italia
| | - Flavia Annesi
- Dipartimento di Biologia e Biotecnologie “Charles Darwin”, Università di Roma “La Sapienza”, Via Alfonso Borelli 50 – 00161 – Roma – Italia
| | - Riccardo Castiglia
- Dipartimento di Biologia e Biotecnologie “Charles Darwin”, Università di Roma “La Sapienza”, Via Alfonso Borelli 50 – 00161 – Roma – Italia
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Graves JAM. How to evolve new vertebrate sex determining genes. Dev Dyn 2012; 242:354-9. [PMID: 23074164 DOI: 10.1002/dvdy.23887] [Citation(s) in RCA: 52] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/08/2012] [Indexed: 02/01/2023] Open
Abstract
Sex determination in vertebrates is accomplished by gonad differentiation in the embryo, which unleashes a cascade of hormones that control sexual phenotype. The pathway by which gonad (testis or ovary) is differentiated is highly conserved in all vertebrates, but the trigger (genetic or environmental) that initiates the whole process may be quite different between lineages. Among species with genetic sex determination, the trigger gene, and its mode of action as a male- or female-dominant, or a dosage sensitive, is known in only a few species. Patterns are starting to emerge that hint at ways in which an autosomal gene may acquire ways of regulating genes at the head of the gonad differentiating pathway, usurp the sex determining function and define new sex chromosomes. The raw material for new sex-determining genes may be genes in the sex differentiating pathway, related genes, or even genes with no known role in sex. The changes that make these genes sex determining can be as simple as a change in the timing or tissue of expression. Intriguingly, certain genes (such as DMRT1 and SOX3) seem to have been independently pressed into service in different ways in distantly related lineages.
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Graphodatsky A, Ferguson-Smith MA, Stanyon R. A short introduction to cytogenetic studies in mammals with reference to the present volume. Cytogenet Genome Res 2012; 137:83-96. [PMID: 22846392 DOI: 10.1159/000341502] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023] Open
Abstract
Genome diversity has long been studied from the comparative cytogenetic perspective. Early workers documented differences between species in diploid chromosome number and fundamental number. Banding methods allowed more detailed descriptions of between-species rearrangements and classes of differentially staining chromosome material. The infusion of molecular methods into cytogenetics provided a third revolution, which is still not exhausted. Chromosome painting has provided a global view of the translocation history of mammalian genome evolution, well summarized in the contributions to this special volume. More recently, FISH of cloned DNA has provided details on defining breakpoint and intrachromosomal marker order, which have helped to document inversions and centromere repositioning. The most recent trend in comparative molecular cytogenetics is to integrate sequencing information in order to formulate and test reconstructions of ancestral genomes and phylogenomic hypotheses derived from comparative cytogenetics. The integration of comparative cytogenetics and sequencing promises to provide an understanding of what drives chromosome rearrangements and genome evolution in general. We believe that the contributions in this volume, in no small way, point the way to the next phase in cytogenetic studies.
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Affiliation(s)
- A Graphodatsky
- Institute of Molecular and Cellular Biology, Siberian Division of the Russian Academy of Sciences, Novosibirsk, Russia
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Conservation of chromosomes syntenic with avian autosomes in squamate reptiles revealed by comparative chromosome painting. Chromosoma 2012; 121:409-18. [DOI: 10.1007/s00412-012-0371-z] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2012] [Revised: 04/05/2012] [Accepted: 04/10/2012] [Indexed: 01/06/2023]
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Kasai F, O'Brien PCM, Ferguson-Smith MA. Reassessment of genome size in turtle and crocodile based on chromosome measurement by flow karyotyping: close similarity to chicken. Biol Lett 2012; 8:631-5. [PMID: 22491763 DOI: 10.1098/rsbl.2012.0141] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023] Open
Abstract
The genome size in turtles and crocodiles is thought to be much larger than the 1.2 Gb of the chicken (Gallus gallus domesticus, GGA), according to the animal genome size database. However, GGA macrochromosomes show extensive homology in the karyotypes of the red eared slider (Trachemys scripta elegans, TSC) and the Nile crocodile (Crocodylus niloticus, CNI), and bird and reptile genomes have been highly conserved during evolution. In this study, size and GC content of all chromosomes are measured from the flow karyotypes of GGA, TSC and CNI. Genome sizes estimated from the total chromosome size demonstrate that TSC and CNI are 1.21 Gb and 1.29 Gb, respectively. This refines previous overestimations and reveals similar genome sizes in chicken, turtle and crocodile. Analysis of chromosome GC content in each of these three species shows a higher GC content in smaller chromosomes than in larger chromosomes. This contrasts with mammals and squamates in which GC content does not correlate with chromosome size. These data suggest that a common ancestor of birds, turtles and crocodiles had a small genome size and a chromosomal size-dependent GC bias, distinct from the squamate lineage.
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Affiliation(s)
- Fumio Kasai
- Department of Veterinary Medicine, University of Cambridge, Cambridge, UK.
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