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Griffin DK, Larkin DM, O’Connor RE, Romanov MN. Dinosaurs: Comparative Cytogenomics of Their Reptile Cousins and Avian Descendants. Animals (Basel) 2022; 13:106. [PMID: 36611715 PMCID: PMC9817885 DOI: 10.3390/ani13010106] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2022] [Revised: 12/22/2022] [Accepted: 12/23/2022] [Indexed: 12/29/2022] Open
Abstract
Reptiles known as dinosaurs pervade scientific and popular culture, while interest in their genomics has increased since the 1990s. Birds (part of the crown group Reptilia) are living theropod dinosaurs. Chromosome-level genome assemblies cannot be made from long-extinct biological material, but dinosaur genome organization can be inferred through comparative genomics of related extant species. Most reptiles apart from crocodilians have both macro- and microchromosomes; comparative genomics involving molecular cytogenetics and bioinformatics has established chromosomal relationships between many species. The capacity of dinosaurs to survive multiple extinction events is now well established, and birds now have more species in comparison with any other terrestrial vertebrate. This may be due, in part, to their karyotypic features, including a distinctive karyotype of around n = 40 (~10 macro and 30 microchromosomes). Similarity in genome organization in distantly related species suggests that the common avian ancestor had a similar karyotype to e.g., the chicken/emu/zebra finch. The close karyotypic similarity to the soft-shelled turtle (n = 33) suggests that this basic pattern was mostly established before the Testudine-Archosaur divergence, ~255 MYA. That is, dinosaurs most likely had similar karyotypes and their extensive phenotypic variation may have been mediated by increased random chromosome segregation and genetic recombination, which is inherently higher in karyotypes with more and smaller chromosomes.
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Affiliation(s)
| | - Denis M. Larkin
- Department of Comparative Biomedical Sciences, Royal Veterinary College, University of London, London NW1 0TU, UK
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2
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Schield DR, Perry BW, Card DC, Pasquesi GIM, Westfall AK, Mackessy SP, Castoe TA. The Rattlesnake W Chromosome: A GC-Rich Retroelement Refugium with Retained Gene Function Across Ancient Evolutionary Strata. Genome Biol Evol 2022; 14:evac116. [PMID: 35867356 PMCID: PMC9447483 DOI: 10.1093/gbe/evac116] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/17/2022] [Indexed: 11/18/2022] Open
Abstract
Sex chromosomes diverge after the establishment of recombination suppression, resulting in differential sex-linkage of genes involved in genetic sex determination and dimorphic traits. This process produces systems of male or female heterogamety wherein the Y and W chromosomes are only present in one sex and are often highly degenerated. Sex-limited Y and W chromosomes contain valuable information about the evolutionary transition from autosomes to sex chromosomes, yet detailed characterizations of the structure, composition, and gene content of sex-limited chromosomes are lacking for many species. In this study, we characterize the female-specific W chromosome of the prairie rattlesnake (Crotalus viridis) and evaluate how recombination suppression and other processes have shaped sex chromosome evolution in ZW snakes. Our analyses indicate that the rattlesnake W chromosome is over 80% repetitive and that an abundance of GC-rich mdg4 elements has driven an overall high degree of GC-richness despite a lack of recombination. The W chromosome is also highly enriched for repeat sequences derived from endogenous retroviruses and likely acts as a "refugium" for these and other retroelements. We annotated 219 putatively functional W-linked genes across at least two evolutionary strata identified based on estimates of sequence divergence between Z and W gametologs. The youngest of these strata is relatively gene-rich, however gene expression across strata suggests retained gene function amidst a greater degree of degeneration following ancient recombination suppression. Functional annotation of W-linked genes indicates a specialization of the W chromosome for reproductive and developmental function since recombination suppression from the Z chromosome.
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Affiliation(s)
- Drew R Schield
- Department of Ecology and Evolutionary Biology, University of Colorado, Boulder, Colorado, USA
| | - Blair W Perry
- Department of Biology, University of Texas at Arlington, Arlington, Texas, USA
- School of Biological Sciences, Washington State University, Pullman, Washington, USA
| | - Daren C Card
- Department of Organismic and Evolutionary Biology, Harvard University, Cambridge, Massachusetts, USA
- Museum of Comparative Zoology, Harvard University, Cambridge, Massachusetts, USA
| | - Giulia I M Pasquesi
- Department of Molecular, Cellular, and Developmental Biology, University of Colorado, Boulder, Colorado, USA
| | - Aundrea K Westfall
- Department of Biology, University of Texas at Arlington, Arlington, Texas, USA
| | - Stephen P Mackessy
- School of Biological Sciences, University of Northern Colorado, Greeley, Colorado, USA
| | - Todd A Castoe
- Department of Biology, University of Texas at Arlington, Arlington, Texas, USA
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3
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Cytogenetic Analysis of the Members of the Snake Genera Cylindrophis, Eryx, Python, and Tropidophis. Genes (Basel) 2022; 13:genes13071185. [PMID: 35885968 PMCID: PMC9318745 DOI: 10.3390/genes13071185] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2022] [Revised: 06/25/2022] [Accepted: 06/28/2022] [Indexed: 02/06/2023] Open
Abstract
The recent discovery of two independently evolved XX/XY sex determination systems in the snake genera Python and Boa sparked a new drive to study the evolution of sex chromosomes in poorly studied lineages of snakes, where female heterogamety was previously assumed. Therefore, we examined seven species from the genera Eryx, Cylindrophis, Python, and Tropidophis by conventional and molecular cytogenetic methods. Despite the fact that these species have similar karyotypes in terms of chromosome number and morphology, we detected variability in the distribution of heterochromatin, telomeric repeats, and rDNA loci. Heterochromatic blocks were mainly detected in the centromeric regions in all species, although accumulations were detected in pericentromeric and telomeric regions in a few macrochromosomes in several of the studied species. All species show the expected topology of telomeric repeats at the edge of all chromosomes, with the exception of Eryx muelleri, where additional accumulations were detected in the centromeres of three pairs of macrochromosomes. The rDNA loci accumulate in one pair of microchromosomes in all Eryx species and in Cylindrophis ruffus, in one macrochromosome pair in Tropidophis melanurus and in two pairs of microchromosomes in Python regius. Sex-specific differences were not detected, suggesting that these species likely have homomorphic, poorly differentiated sex chromosomes.
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Chromosome-level genome assembly of Asian yellow pond turtle (Mauremys mutica) with temperature-dependent sex determination system. Sci Rep 2022; 12:7905. [PMID: 35550586 PMCID: PMC9098631 DOI: 10.1038/s41598-022-12054-2] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2022] [Accepted: 04/21/2022] [Indexed: 12/14/2022] Open
Abstract
Knowledge of sex determination has important implications in physiology, ecology and genetics, but the evolutionary mechanisms of sex determination systems in turtles have not been fully elucidated, due to a lack of reference genomes. Here, we generate a high-quality genome assembly of Asian yellow pond turtle (Mauremys mutica) using continuous long-read (PacBio platform), Illumina, and high-throughput chromatin conformation capture (Hi-C) technologies. The M. mutica haplotype has a genome size of 2.23 Gb with a contig N50 of 8.53 Mb and scaffold N50 of 141.98 Mb. 99.98% sequences of the total assembly are anchored to 26 pseudochromosomes. Comparative genomics analysis indicated that the lizard-snake-tuatara clade diverged from the bird-crocodilian-turtle clade at approximately 267.0-312.3 Mya. Intriguingly, positive selected genes are mostly enriched in the calcium signaling pathway and neuroactive ligand-receptor interaction, which are involved in the process of temperature-dependent sex determination. These findings provide important evolutionary insights into temperature-dependent sex determination system.
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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: 11] [Impact Index Per Article: 3.7] [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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Waters PD, Patel HR, Ruiz-Herrera A, Álvarez-González L, Lister NC, Simakov O, Ezaz T, Kaur P, Frere C, Grützner F, Georges A, Graves JAM. Microchromosomes are building blocks of bird, reptile, and mammal chromosomes. Proc Natl Acad Sci U S A 2021; 118:e2112494118. [PMID: 34725164 PMCID: PMC8609325 DOI: 10.1073/pnas.2112494118] [Citation(s) in RCA: 64] [Impact Index Per Article: 21.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/09/2021] [Indexed: 12/11/2022] Open
Abstract
Microchromosomes, once considered unimportant shreds of the chicken genome, are gene-rich elements with a high GC content and few transposable elements. Their origin has been debated for decades. We used cytological and whole-genome sequence comparisons, and chromosome conformation capture, to trace their origin and fate in genomes of reptiles, birds, and mammals. We find that microchromosomes as well as macrochromosomes are highly conserved across birds and share synteny with single small chromosomes of the chordate amphioxus, attesting to their origin as elements of an ancient animal genome. Turtles and squamates (snakes and lizards) share different subsets of ancestral microchromosomes, having independently lost microchromosomes by fusion with other microchromosomes or macrochromosomes. Patterns of fusions were quite different in different lineages. Cytological observations show that microchromosomes in all lineages are spatially separated into a central compartment at interphase and during mitosis and meiosis. This reflects higher interaction between microchromosomes than with macrochromosomes, as observed by chromosome conformation capture, and suggests some functional coherence. In highly rearranged genomes fused microchromosomes retain most ancestral characteristics, but these may erode over evolutionary time; surprisingly, de novo microchromosomes have rapidly adopted high interaction. Some chromosomes of early-branching monotreme mammals align to several bird microchromosomes, suggesting multiple microchromosome fusions in a mammalian ancestor. Subsequently, multiple rearrangements fueled the extraordinary karyotypic diversity of therian mammals. Thus, microchromosomes, far from being aberrant genetic elements, represent fundamental building blocks of amniote chromosomes, and it is mammals, rather than reptiles and birds, that are atypical.
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Affiliation(s)
- Paul D Waters
- School of Biotechnology and Biomolecular Science, Faculty of Science, UNSW Sydney, Sydney, NSW 2052, Australia
| | - Hardip R Patel
- The John Curtin School of Medical Research, Australian National University, Canberra, ACT 2601, Australia
| | - Aurora Ruiz-Herrera
- Departament de Biologia Cel·lular, Fisiologia i Immunologia, Universitat Autònoma de Barcelona, Cerdanyola del Vallès 08193, Spain
- Genome Integrity and Instability Group, Institut de Biotecnologia i Biomedicina, Universitat Autònoma de Barcelona, Cerdanyola del Vallès 08193, Spain
| | - Lucía Álvarez-González
- Departament de Biologia Cel·lular, Fisiologia i Immunologia, Universitat Autònoma de Barcelona, Cerdanyola del Vallès 08193, Spain
- Genome Integrity and Instability Group, Institut de Biotecnologia i Biomedicina, Universitat Autònoma de Barcelona, Cerdanyola del Vallès 08193, Spain
| | - Nicholas C Lister
- School of Biotechnology and Biomolecular Science, Faculty of Science, UNSW Sydney, Sydney, NSW 2052, Australia
| | - Oleg Simakov
- Department of Neurosciences and Developmental Biology, University of Vienna, 1010 Vienna, Austria
| | - Tariq Ezaz
- Institute for Applied Ecology, University of Canberra, Canberra, ACT 2601, Australia
| | - Parwinder Kaur
- UWA School of Agriculture and Environment, The University of Western Australia, Crawley, WA 6009, Australia
| | - Celine Frere
- Global Change Ecology Research Group, University of the Sunshine Coast, Sippy Downs, QLD 4556, Australia
| | - Frank Grützner
- School of Biological Sciences, University of Adelaide, Adelaide, SA 5000, Australia
| | - Arthur Georges
- Institute for Applied Ecology, University of Canberra, Canberra, ACT 2601, Australia
| | - Jennifer A Marshall Graves
- Institute for Applied Ecology, University of Canberra, Canberra, ACT 2601, Australia;
- School of Life Sciences, La Trobe University, Bundoora, VIC 3068, Australia
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7
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Singchat W, Ahmad SF, Sillapaprayoon S, Muangmai N, Duengkae P, Peyachoknagul S, O’Connor RE, Griffin DK, Srikulnath K. Partial Amniote Sex Chromosomal Linkage Homologies Shared on Snake W Sex Chromosomes Support the Ancestral Super-Sex Chromosome Evolution in Amniotes. Front Genet 2020; 11:948. [PMID: 33014016 PMCID: PMC7461878 DOI: 10.3389/fgene.2020.00948] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2020] [Accepted: 07/28/2020] [Indexed: 12/11/2022] Open
Abstract
Squamate reptile chromosome 2 (SR2) is thought to be an important remnant of an ancestral amniote super-sex chromosome, but a recent study showed that the Siamese cobra W sex chromosome is also a part of this larger ancestral chromosome. To confirm the existence of an ancestral amniote super-sex chromosome and understand the mechanisms of amniote sex chromosome evolution, chromosome maps of two snake species [Russell's viper: Daboia russelii (DRU) and the common tiger snake: Notechis scutatus (NSC)] were constructed using bacterial artificial chromosomes (BACs) derived from chicken and zebra finch libraries containing amniote sex chromosomal linkages. Sixteen BACs were mapped on the W sex chromosome of DRU and/or NSC, suggesting that these BACs contained a common genomic region shared with the W sex chromosome of these snakes. Two of the sixteen BACs were co-localized to DRU2 and NSC2, corresponding to SR2. Prediction of genomic content from all BACs mapped on snake W sex chromosomes revealed a large proportion of long interspersed nuclear element (LINE) and short interspersed nuclear element (SINE) retrotransposons. These results led us to predict that amplification of LINE and SINE may have occurred on snake W chromosomes during evolution. Genome compartmentalization, such as transposon amplification, might be the key factor influencing chromosome structure and differentiation. Multiple sequence alignments of all BACs mapped on snake W sex chromosomes did not reveal common sequences. Our findings indicate that the SR2 and snake W sex chromosomes may have been part of a larger ancestral amniote super-sex chromosome, and support the view of sex chromosome evolution as a colorful myriad of situations and trajectories in which many diverse processes are in action.
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Affiliation(s)
- Worapong Singchat
- Laboratory of Animal Cytogenetics and Comparative Genomics (ACCG), Department of Genetics, Faculty of Science, Kasetsart University, Bangkok, Thailand
- Special Research Unit for Wildlife Genomics (SRUWG), Department of Forest Biology, Faculty of Forestry, Kasetsart University, Bangkok, Thailand
| | - Syed Farhan Ahmad
- Laboratory of Animal Cytogenetics and Comparative Genomics (ACCG), Department of Genetics, Faculty of Science, Kasetsart University, Bangkok, Thailand
- Special Research Unit for Wildlife Genomics (SRUWG), Department of Forest Biology, Faculty of Forestry, Kasetsart University, Bangkok, Thailand
| | - Siwapech Sillapaprayoon
- Laboratory of Animal Cytogenetics and Comparative Genomics (ACCG), Department of Genetics, Faculty of Science, Kasetsart University, Bangkok, Thailand
- Special Research Unit for Wildlife Genomics (SRUWG), Department of Forest Biology, Faculty of Forestry, Kasetsart University, Bangkok, Thailand
| | - Narongrit Muangmai
- Department of Fishery Biology, Faculty of Fisheries, Kasetsart University, Bangkok, Thailand
| | - Prateep Duengkae
- Special Research Unit for Wildlife Genomics (SRUWG), Department of Forest Biology, Faculty of Forestry, Kasetsart University, Bangkok, Thailand
| | - Surin Peyachoknagul
- Laboratory of Animal Cytogenetics and Comparative Genomics (ACCG), Department of Genetics, Faculty of Science, Kasetsart University, Bangkok, Thailand
| | | | - Darren K. Griffin
- School of Biosciences, University of Kent, Canterbury, United Kingdom
| | - Kornsorn Srikulnath
- Laboratory of Animal Cytogenetics and Comparative Genomics (ACCG), Department of Genetics, Faculty of Science, Kasetsart University, Bangkok, Thailand
- Special Research Unit for Wildlife Genomics (SRUWG), Department of Forest Biology, Faculty of Forestry, Kasetsart University, Bangkok, Thailand
- Center for Advanced Studies in Tropical Natural Resources, National Research University-Kasetsart University, Kasetsart University, Bangkok, Thailand
- Center of Excellence on Agricultural Biotechnology (AG-BIO/PERDO-CHE), Bangkok, Thailand
- Omics Center for Agriculture, Bioresources, Food and Health, Kasetsart University (OmiKU), Bangkok, Thailand
- Amphibian Research Center, Hiroshima University, Higashihiroshima, Japan
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8
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Evolutionary Insights of the ZW Sex Chromosomesin Snakes: A New Chapter Added by the AmazonianPuffing Snakes of the Genus Spilotes. Genes (Basel) 2019; 10:genes10040288. [PMID: 30970650 PMCID: PMC6523457 DOI: 10.3390/genes10040288] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2019] [Revised: 03/12/2019] [Accepted: 03/31/2019] [Indexed: 01/16/2023] Open
Abstract
Amazonian puffing snakes (Spilotes; Colubridae) are snakes widely distributed in the Neotropical region. However, chromosomal data are scarce in this group and, when available, are only limited to karyotype description using conventional staining. In this paper, we focused on the process of karyotype evolution and trends for sex chromosomes in two Amazonian Puffer Snakes (S. pulllatus and S. sulphureus). We performed an extensive karyotype characterization using conventional and molecular cytogenetic approaches. The karyotype of S. sulphureus (presented here for the first time) exhibits a 2n = 36, similar to that previously described in S. pullatus. Both species have highly differentiated ZZ/ZW sex chromosomes, where the W chromosome is highly heterochromatic in S. pullatus but euchromatic in S. sulphureus. Both W chromosomes are homologous between these species as revealed by cross-species comparative genomic hybridization, even with heterogeneous distributions of several repetitive sequences across their genomes, including on the Z and on the W chromosomes. Our study provides evidence that W chromosomes in these two species have shared ancestry.
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9
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Griffin DK, Larkin DM, O'Connor RE. Time lapse: A glimpse into prehistoric genomics. Eur J Med Genet 2019; 63:103640. [PMID: 30922926 PMCID: PMC7026692 DOI: 10.1016/j.ejmg.2019.03.004] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2019] [Accepted: 03/10/2019] [Indexed: 11/28/2022]
Abstract
For the purpose of this review, ‘time-lapse’ refers to the reconstruction of ancestral (in this case dinosaur) karyotypes using genome assemblies of extant species. Such reconstructions are only usually possible when genomes are assembled to ‘chromosome level’ i.e. a complete representation of all the sequences, correctly ordered contiguously on each of the chromosomes. Recent paleontological evidence is very clear that birds are living dinosaurs, the latest example of dinosaurs emerging from a catastrophic extinction event. Non-avian dinosaurs (ever present in the public imagination through art, and broadcast media) emerged some 240 million years ago and have displayed incredible phenotypic diversity. Here we report on our recent studies to infer the overall karyotype of the Theropod dinosaur lineage from extant avian chromosome level genome assemblies. Our work first focused on determining the likely karyotype of the avian ancestor (most likely a chicken-sized, two-legged, feathered, land dinosaur from the Jurassic period) finding karyotypic similarity to the chicken. We then took the work further to determine the likely karyotype of the bird-lizard ancestor and the chromosomal changes (chiefly translocations and inversions) that occurred between then and modern birds. A combination of bioinformatics and cross-species fluorescence in situ hybridization (zoo-FISH) uncovered a considerable number of translocations and fissions from a ‘lizard-like’ genome structure of 2n = 36–46 to one similar to that of soft-shelled turtles (2n = 66) from 275 to 255 million years ago (mya). Remarkable karyotypic similarities between some soft-shelled turtles and chicken suggests that there were few translocations from the bird-turtle ancestor (plus ∼7 fissions) through the dawn of the dinosaurs and pterosaurs, through the theropod linage and on to most to modern birds. In other words, an avian-like karyotype was in place about 240mya when the dinosaurs and pterosaurs first emerged. We mapped 49 chromosome inversions from then to the present day, uncovering some gene ontology enrichment in evolutionary breakpoint regions. This avian-like karyotype with its many (micro)chromosomes provides the basis for variation (the driver of natural selection) through increased random segregation and recombination. It may therefore contribute to the ability of dinosaurs to survive multiple extinction events, emerging each time as speciose and diverse.
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Affiliation(s)
- Darren K Griffin
- School of Biosciences, University of Kent, Canterbury, CT2 7NJ, UK.
| | - Denis M Larkin
- Department of Comparative Biomedical Sciences, Royal Veterinary College, University of London, London, NW1 0TU, UK.
| | - Rebecca E O'Connor
- School of Biosciences, University of Kent, Canterbury, CT2 7NJ, UK. R.O'
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10
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O'Connor RE, Romanov MN, Kiazim LG, Barrett PM, Farré M, Damas J, Ferguson-Smith M, Valenzuela N, Larkin DM, Griffin DK. Reconstruction of the diapsid ancestral genome permits chromosome evolution tracing in avian and non-avian dinosaurs. Nat Commun 2018; 9:1883. [PMID: 29784931 PMCID: PMC5962605 DOI: 10.1038/s41467-018-04267-9] [Citation(s) in RCA: 49] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2017] [Accepted: 04/12/2018] [Indexed: 01/07/2023] Open
Abstract
Genomic organisation of extinct lineages can be inferred from extant chromosome-level genome assemblies. Here, we apply bioinformatic and molecular cytogenetic approaches to determine the genomic structure of the diapsid common ancestor. We then infer the events that likely occurred along this lineage from theropod dinosaurs through to modern birds. Our results suggest that most elements of a typical ‘avian-like’ karyotype (40 chromosome pairs, including 30 microchromosomes) were in place before the divergence of turtles from birds ~255 mya. This genome organisation therefore predates the emergence of early dinosaurs and pterosaurs and the evolution of flight. Remaining largely unchanged interchromosomally through the dinosaur–theropod route that led to modern birds, intrachromosomal changes nonetheless reveal evolutionary breakpoint regions enriched for genes with ontology terms related to chromatin organisation and transcription. This genomic structure therefore appears highly stable yet contributes to a large degree of phenotypic diversity, as well as underpinning adaptive responses to major environmental disruptions via intrachromosomal repatterning. Ancient diapsids diverged into the lineages leading to turtles and birds over 250 million years ago. Here, the authors use genomic and molecular cytogenetic analyses of modern species to infer the genome structure of the diapsid common ancestor (DCA) and the changes occurring along the lineage to birds through theropod dinosaurs.
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Affiliation(s)
- Rebecca E O'Connor
- School of Biosciences, University of Kent, Canterbury, Kent, CT2 7NJ, UK
| | - Michael N Romanov
- School of Biosciences, University of Kent, Canterbury, Kent, CT2 7NJ, UK
| | - Lucas G Kiazim
- School of Biosciences, University of Kent, Canterbury, Kent, CT2 7NJ, UK
| | - Paul M Barrett
- Department of Earth Sciences, Natural History Museum, Cromwell Road, London, SW7 5BD, UK
| | - Marta Farré
- Department of Comparative Biomedical Sciences, Royal Veterinary College, University of London, London, NW1 0TU, UK
| | - Joana Damas
- Department of Comparative Biomedical Sciences, Royal Veterinary College, University of London, London, NW1 0TU, UK
| | | | - Nicole Valenzuela
- Department of Ecology, Evolution, and Organismal Biology, Iowa State University, Iowa, IA, 50011, USA
| | - Denis M Larkin
- Department of Comparative Biomedical Sciences, Royal Veterinary College, University of London, London, NW1 0TU, UK
| | - Darren K Griffin
- School of Biosciences, University of Kent, Canterbury, Kent, CT2 7NJ, UK.
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11
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Laopichienpong N, Muangmai N, Chanhome L, Suntrarachun S, Twilprawat P, Peyachoknagul S, Srikulnath K. Evolutionary Dynamics of the Gametologous CTNNB1 Gene on the Z and W Chromosomes of Snakes. J Hered 2018; 108:142-151. [PMID: 28175328 DOI: 10.1093/jhered/esw074] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2016] [Accepted: 10/13/2016] [Indexed: 12/29/2022] Open
Abstract
Snakes exhibit genotypic sex determination with female heterogamety (ZZ males and ZW females), and the state of sex chromosome differentiation also varies among lineages. To investigate the evolutionary history of homologous genes located in the nonrecombining region of differentiated sex chromosomes in snakes, partial sequences of the gametologous CTNNB1 gene were analyzed for 12 species belonging to henophid (Cylindrophiidae, Xenopeltidae, and Pythonidae) and caenophid snakes (Viperidae, Elapidae, and Colubridae). Nonsynonymous/synonymous substitution ratios (Ka/Ks) in coding sequences were low (Ka/Ks < 1) between CTNNB1Z and CTNNB1W, suggesting that these 2 genes may have similar functional properties. However, frequencies of intron sequence substitutions and insertion–deletions were higher in CTNNB1Z than CTNNB1W, suggesting that Z-linked sequences evolved faster than W-linked sequences. Molecular phylogeny based on both intron and exon sequences showed the presence of 2 major clades: 1) Z-linked sequences of Caenophidia and 2) W-linked sequences of Caenophidia clustered with Z-linked sequences of Henophidia, which suggests that the sequence divergence between CTNNB1Z and CTNNB1W in Caenophidia may have occurred by the cessation of recombination after the split from Henophidia.
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Affiliation(s)
- Nararat Laopichienpong
- Laboratory of Animal Cytogenetics and Comparative Genomics (ACCG), Department of Genetics, Faculty of Science, Kasetsart University, 50 Ngamwongwan, Chatuchak, Bangkok, Thailand
| | - Narongrit Muangmai
- Department of Fishery Biology, Faculty of Fisheries, Kasetsart University, Bangkok, Thailand
| | - Lawan Chanhome
- Snake Farm, Queen Saovabha Memorial Institute, The Thai Red Cross Society, Bangkok, Thailand
| | - Sunutcha Suntrarachun
- Department of Research and Development, Queen Saovabha Memorial Institute, The Thai Red Cross Society, Bangkok, Thailand
| | - Panupon Twilprawat
- Laboratory of Animal Cytogenetics and Comparative Genomics (ACCG), Department of Genetics, Faculty of Science, Kasetsart University, 50 Ngamwongwan, Chatuchak, Bangkok, Thailand
| | - Surin Peyachoknagul
- Laboratory of Animal Cytogenetics and Comparative Genomics (ACCG), 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, Kasetsart University, Bangkok, Thailand
| | - Kornsorn Srikulnath
- Laboratory of Animal Cytogenetics and Comparative Genomics (ACCG), 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, Kasetsart University, Bangkok, Thailand
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12
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Abbott JK, Nordén AK, Hansson B. Sex chromosome evolution: historical insights and future perspectives. Proc Biol Sci 2018; 284:rspb.2016.2806. [PMID: 28469017 PMCID: PMC5443938 DOI: 10.1098/rspb.2016.2806] [Citation(s) in RCA: 76] [Impact Index Per Article: 12.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2017] [Accepted: 04/04/2017] [Indexed: 12/26/2022] Open
Abstract
Many separate-sexed organisms have sex chromosomes controlling sex determination. Sex chromosomes often have reduced recombination, specialized (frequently sex-specific) gene content, dosage compensation and heteromorphic size. Research on sex determination and sex chromosome evolution has increased over the past decade and is today a very active field. However, some areas within the field have not received as much attention as others. We therefore believe that a historic overview of key findings and empirical discoveries will put current thinking into context and help us better understand where to go next. Here, we present a timeline of important conceptual and analytical models, as well as empirical studies that have advanced the field and changed our understanding of the evolution of sex chromosomes. Finally, we highlight gaps in our knowledge so far and propose some specific areas within the field that we recommend a greater focus on in the future, including the role of ecology in sex chromosome evolution and new multilocus models of sex chromosome divergence.
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Affiliation(s)
- Jessica K Abbott
- Department of Biology, Lund University, Sölvegatan 37, 223 62 Lund, Sweden
| | - Anna K Nordén
- Department of Biology, Lund University, Sölvegatan 37, 223 62 Lund, Sweden
| | - Bengt Hansson
- Department of Biology, Lund University, Sölvegatan 37, 223 62 Lund, Sweden
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Gamble T, Castoe TA, Nielsen SV, Banks JL, Card DC, Schield DR, Schuett GW, Booth W. The Discovery of XY Sex Chromosomes in a Boa and Python. Curr Biol 2017; 27:2148-2153.e4. [DOI: 10.1016/j.cub.2017.06.010] [Citation(s) in RCA: 63] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2016] [Revised: 04/21/2017] [Accepted: 06/02/2017] [Indexed: 10/19/2022]
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Laopichienpong N, Tawichasri P, Chanhome L, Phatcharakullawarawat R, Singchat W, Kantachumpoo A, Muangmai N, Suntrarachun S, Matsubara K, Peyachoknagul S, Srikulnath K. A novel method of caenophidian snake sex identification using molecular markers based on two gametologous genes. Ecol Evol 2017; 7:4661-4669. [PMID: 28690796 PMCID: PMC5496543 DOI: 10.1002/ece3.3057] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2017] [Revised: 04/11/2017] [Accepted: 04/24/2017] [Indexed: 12/24/2022] Open
Abstract
Sex identification provides important information for ecological and evolutionary studies, as well as benefiting snake conservation management. Traditional methods such as cloacal probing or cloacal popping are counterproductive for sex identification concerning very small species, resulting in difficulties in the management of their breeding programs. In this study, the nucleotide sequences of gametologous genes (CTNNB1 and WAC genes) were used for the development of molecular sexing markers in caenophidian snakes. Two candidate markers were developed with the two primer sets, and successfully amplified by a single band on the agarose gel in male (ZZ) and two bands, differing in fragment sizes, in female (ZW) of 16 caenophidian snakes for CTNNB1 and 12 caenophidian snakes for WAC. Another candidate marker was developed with the primer set to amplify the specific sequence for CTNNB1W homolog, and the PCR products were successfully obtained in a female‐specific 250‐bp DNA bands. The three candidate PCR sexing markers provide a simple sex identification method based on the amplification of gametologous genes, and they can be used to facilitate effective caenophidian snake conservation and management programs.
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Affiliation(s)
- Nararat Laopichienpong
- Laboratory of Animal Cytogenetics and Comparative Genomics (ACCG) Department of Genetics Faculty of Science Kasetsart University Bangkok Thailand.,Animal Breeding and Genetics Consortium of Kasetsart University (ABG - KU) Bangkok Thailand
| | - Panupong Tawichasri
- Laboratory of Animal Cytogenetics and Comparative Genomics (ACCG) Department of Genetics Faculty of Science Kasetsart University Bangkok Thailand.,Animal Breeding and Genetics Consortium of Kasetsart University (ABG - KU) Bangkok Thailand
| | - Lawan Chanhome
- Snake Farm Queen Saovabha Memorial Institute The Thai Red Cross Society Bangkok Thailand
| | | | - Worapong Singchat
- Laboratory of Animal Cytogenetics and Comparative Genomics (ACCG) Department of Genetics Faculty of Science Kasetsart University Bangkok Thailand.,Animal Breeding and Genetics Consortium of Kasetsart University (ABG - KU) Bangkok Thailand
| | - Attachai Kantachumpoo
- Laboratory of Animal Cytogenetics and Comparative Genomics (ACCG) Department of Genetics Faculty of Science Kasetsart University Bangkok Thailand.,Animal Breeding and Genetics Consortium of Kasetsart University (ABG - KU) Bangkok Thailand.,Center for Advanced Studies in Tropical Natural Resources National Research University-Kasetsart University Thailand (CASTNARNRU-KUThailand) Kasetsart University Bangkok Thailand
| | - Narongrit Muangmai
- Department of Fishery Biology Faculty of Fisheries Kasetsart University Bangkok Thailand
| | - Sunutcha Suntrarachun
- Department of Research and Development Queen Saovabha Memorial Institute The Thai Red Cross Society Bangkok Thailand
| | - Kazumi Matsubara
- Research Center for Bioinformatics and Biosciences National Research Institute of Fisheries Science Japan Fisheries Research and Education Agency Yokohama Kanagawa Japan
| | - Surin Peyachoknagul
- Laboratory of Animal Cytogenetics and Comparative Genomics (ACCG) Department of Genetics Faculty of Science Kasetsart University Bangkok Thailand.,Center for Advanced Studies in Tropical Natural Resources National Research University-Kasetsart University Thailand (CASTNARNRU-KUThailand) Kasetsart University Bangkok Thailand.,Department of Biology Faculty of Science Naresuan University Phitsanulok Thailand
| | - Kornsorn Srikulnath
- Laboratory of Animal Cytogenetics and Comparative Genomics (ACCG) Department of Genetics Faculty of Science Kasetsart University Bangkok Thailand.,Animal Breeding and Genetics Consortium of Kasetsart University (ABG - KU) Bangkok Thailand.,Center for Advanced Studies in Tropical Natural Resources National Research University-Kasetsart University Thailand (CASTNARNRU-KUThailand) Kasetsart University Bangkok Thailand
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Lisachov AP, Trifonov VA, Giovannotti M, Ferguson-Smith MA, Borodin PM. Immunocytological analysis of meiotic recombination in two anole lizards (Squamata, Dactyloidae). COMPARATIVE CYTOGENETICS 2017; 11:129-141. [PMID: 28919954 PMCID: PMC5599703 DOI: 10.3897/compcytogen.v11i1.10916] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/25/2016] [Accepted: 01/16/2017] [Indexed: 05/13/2023]
Abstract
Although the evolutionary importance of meiotic recombination is not disputed, the significance of interspecies differences in the recombination rates and recombination landscapes remains under-appreciated. Recombination rates and distribution of chiasmata have been examined cytologically in many mammalian species, whereas data on other vertebrates are scarce. Immunolocalization of the protein of the synaptonemal complex (SYCP3), centromere proteins and the mismatch-repair protein MLH1 was used, which is associated with the most common type of recombination nodules, to analyze the pattern of meiotic recombination in the male of two species of iguanian lizards, Anolis carolinensis Voigt, 1832 and Deiroptyx coelestinus (Cope, 1862). These species are separated by a relatively long evolutionary history although they retain the ancestral iguanian karyotype. In both species similar and extremely uneven distributions of MLH1 foci along the macrochromosome bivalents were detected: approximately 90% of crossovers were located at the distal 20% of the chromosome arm length. Almost total suppression of recombination in the intermediate and proximal regions of the chromosome arms contradicts the hypothesis that "homogenous recombination" is responsible for the low variation in GC content across the anole genome. It also leads to strong linkage disequilibrium between the genes located in these regions, which may benefit conservation of co-adaptive gene arrays responsible for the ecological adaptations of the anoles.
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Affiliation(s)
- Artem P. Lisachov
- Institute of Cytology and Genetics, Russian Academy of Sciences, Siberian Branch, Novosibirsk 630090, Russia
| | - Vladimir A. Trifonov
- Institute of Molecular and Cellular Biology, Russian Academy of Sciences, Siberian Branch, Novosibirsk 630090, Russia
- Novosibirsk State University, Novosibirsk 630090, Russia
| | - Massimo Giovannotti
- Dipartimento di Scienze della Vita e dell’Ambiente, Università Politecnica delle Marche, via Brecce Bianche, 60131 Ancona, Italy
| | - Malcolm A. Ferguson-Smith
- Cambridge Resource Centre for Comparative Genomics, Department of Veterinary Medicine, University of Cambridge, Madingley Road, Cambridge CB3 0ES, UK
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Matsubara K, Nishida C, Matsuda Y, Kumazawa Y. Sex chromosome evolution in snakes inferred from divergence patterns of two gametologous genes and chromosome distribution of sex chromosome-linked repetitive sequences. ZOOLOGICAL LETTERS 2016; 2:19. [PMID: 27570632 PMCID: PMC5002183 DOI: 10.1186/s40851-016-0056-1] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 04/09/2016] [Accepted: 08/18/2016] [Indexed: 06/06/2023]
Abstract
BACKGROUND The discovery of differentially organized sex chromosome systems suggests that heteromorphic sex chromosomes evolved from a pair of homologous chromosomes. Whereas karyotypes are highly conserved in alethinophidian snakes, the degeneration status of the W chromosomes varies among species. The Z and W chromosomes are morphologically homomorphic in henophidian species, whereas in snakes belonging to caenophidian families the W chromosomes are highly degenerated. Snakes therefore are excellent animal models in which to study sex chromosome evolution. Herein, we investigated the differentiation processes for snake sex chromosomes using both coding and repetitive sequences. We analyzed phylogenetic relationships of CTNNB1 and WAC genes, localized to the centromeric and telomeric regions, respectively, of the long arms on snake sex chromosomes, and chromosome distribution of sex chromosome-linked repetitive sequences in several henophidian and caenophidian species. RESULTS Partial or full-length coding sequences of CTNNB1 and WAC were identified for Z homologs of henophidian species from Tropidophiidae, Boidae, Cylindrophiidae, Xenopeltidae, and Pythonidae, and for Z and W homologs of caenophidian species from Acrochordidae, Viperidae, Elapidae, and Colubridae. Female-specific sequences for the two genes were not found in the henophidian (boid and pythonid) species examined. Phylogenetic trees constructed using each gene showed that the Z and W homologs of the caenophidian species cluster separately. The repetitive sequence isolated from the W chromosome heterochromatin of the colubrid Elaphe quadrivirgata and a microsatellite motif (AGAT)8 were strongly hybridized with W chromosomes of the viperid and colubrid species examined. CONCLUSION Our phylogenetic analyses suggest that the cessation of recombination between the Z and W homologs of CTNNB1 and WAC predated the diversification of the caenophidian families. As the repetitive sequences on the W chromosomes were shared among viperid and colubrid species, heterochromatinization of the proto-W chromosome appears to have occurred before the splitting of these two groups. These results collectively suggest that differentiation of the proto-Z and proto-W chromosomes extended to wide regions on the sex chromosomes in the common ancestor of caenophidian families during a relatively short period.
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Affiliation(s)
- Kazumi Matsubara
- Department of Information and Basic Science and Research Center for Biological Diversity, Graduate School of Natural Sciences, Nagoya City University, 1 Yamanohata, Mizuho-cho, Mizuho-ku, Nagoya, Aichi 467-8501 Japan
- Laboratory of Animal Genetics, Department of Applied Molecular Biosciences, Graduate School of Bioagricultural Sciences, Nagoya University, Furo-cho, Chikusa-ku, Nagoya, Aichi 464-8601 Japan
- Current affiliation: Research Center for Bioinformatics and Biosciences, National Research Institute of Fisheries Science, Japan Fisheries Research and Education Agency, Yokohama, Kanagawa 236-8648 Japan
| | - Chizuko Nishida
- Department of Biological Science, Faculty of Science, Hokkaido University, North 10 West 8, Kita-ku, Sapporo, Hokkaido 060-0810 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 464-8601 Japan
- Avian Bioscience Research Center, Graduate School of Bioagricultural Sciences, Nagoya University, Furo-cho, Chikusa-ku, Nagoya, Aichi 464-8601 Japan
| | - Yoshinori Kumazawa
- Department of Information and Basic Science and Research Center for Biological Diversity, Graduate School of Natural Sciences, Nagoya City University, 1 Yamanohata, Mizuho-cho, Mizuho-ku, Nagoya, Aichi 467-8501 Japan
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Unraveling the Sex Chromosome Heteromorphism of the Paradoxical Frog Pseudis tocantins. PLoS One 2016; 11:e0156176. [PMID: 27214234 PMCID: PMC4877019 DOI: 10.1371/journal.pone.0156176] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2016] [Accepted: 05/10/2016] [Indexed: 11/25/2022] Open
Abstract
The paradoxical frog Pseudis tocantins is the only species in the Hylidae family with known heteromorphic Z and W sex chromosomes. The Z chromosome is metacentric and presents an interstitial nucleolar organizer region (NOR) on the long arm that is adjacent to a pericentromeric heterochromatic band. In contrast, the submetacentric W chromosome carries a pericentromeric NOR on the long arm, which is adjacent to a clearly evident heterochromatic band that is larger than the band found on the Z chromosome and justify the size difference observed between these chromosomes. Here, we provide evidence that the non-centromeric heterochromatic bands in Zq and Wq differ not only in size and location but also in composition, based on comparative genomic hybridization (CGH) and an analysis of the anuran PcP190 satellite DNA. The finding of PcP190 sequences in P. tocantins extends the presence of this satellite DNA, which was previously detected among Leptodactylidae and Hylodidae, suggesting that this family of repetitive DNA is even older than it was formerly considered. Seven groups of PcP190 sequences were recognized in the genome of P. tocantins. PcP190 probes mapped to the heterochromatic band in Wq, and a Southern blot analysis indicated the accumulation of PcP190 in the female genome of P. tocantins, which suggests the involvement of this satellite DNA in the evolution of the sex chromosomes of this species.
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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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Matsubara K, Uno Y, Srikulnath K, Seki R, Nishida C, Matsuda Y. Molecular cloning and characterization of satellite DNA sequences from constitutive heterochromatin of the habu snake (Protobothrops flavoviridis, Viperidae) and the Burmese python (Python bivittatus, Pythonidae). Chromosoma 2015. [DOI: 10.1007/s00412-015-0529-6] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
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Matsubara K, O’Meally D, Azad B, Georges A, Sarre SD, Graves JAM, Matsuda Y, Ezaz T. Amplification of microsatellite repeat motifs is associated with the evolutionary differentiation and heterochromatinization of sex chromosomes in Sauropsida. Chromosoma 2015; 125:111-23. [DOI: 10.1007/s00412-015-0531-z] [Citation(s) in RCA: 61] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2015] [Revised: 07/01/2015] [Accepted: 07/03/2015] [Indexed: 01/05/2023]
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Kerkis I, Hayashi MAF, Prieto da Silva ARB, Pereira A, De Sá Júnior PL, Zaharenko AJ, Rádis-Baptista G, Kerkis A, Yamane T. State of the art in the studies on crotamine, a cell penetrating peptide from South American rattlesnake. BIOMED RESEARCH INTERNATIONAL 2014; 2014:675985. [PMID: 24551848 PMCID: PMC3914522 DOI: 10.1155/2014/675985] [Citation(s) in RCA: 45] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/15/2013] [Revised: 08/05/2013] [Accepted: 08/08/2013] [Indexed: 12/03/2022]
Abstract
Animal venoms comprise a naturally selected cocktail of bioactive peptides/proteins and other molecules, each of which playing a defined role thanks to the highly specific interactions with diverse molecular targets found in the prey. Research focused on isolation, structural, and functional characterizations of novel natural biologics (bioactive peptides/proteins from natural sources) has a long way to go through from the basic science to clinical applications. Herein, we overview the structural and functional characteristics of the myoneurotoxin crotamine, firstly isolated from the South American rattlesnake venom. Crotamine is the first venom peptide classified as a natural cell penetrating and antimicrobial peptide (CPP and AMP) with a more pronounced antifungal activity. In contrast to other known natural CPPs and AMPs, crotamine demonstrates a wide spectrum of biological activities with potential biotechnological and therapeutic values. More recent studies have demonstrated the selective in vitro anticancer activity of crotamine. In vivo, using a murine melanoma model, it was shown that crotamine delays tumor implantation, inhibits tumor cells proliferation, and also increases the survival of mice engrafted with subcutaneous melanoma. The structural and functional properties and also the possible biotechnological applications of minimized molecules derived from crotamine are also discussed.
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Affiliation(s)
- Irina Kerkis
- Laboratório de Genética, Instituto Butantan, Av. Vital Brasil, 1500 05503-900 São Paulo, SP, Brazil
| | - Mirian A. F. Hayashi
- Departamento de Farmacologia, Universidade Federal de São Paulo (UNIFESP), São Paulo, SP, Brazil
| | | | - Alexandre Pereira
- Laboratório de Genética, Instituto Butantan, Av. Vital Brasil, 1500 05503-900 São Paulo, SP, Brazil
| | - Paulo Luiz De Sá Júnior
- Laboratório de Genética, Instituto Butantan, Av. Vital Brasil, 1500 05503-900 São Paulo, SP, Brazil
| | - Andre J. Zaharenko
- Laboratório de Genética, Instituto Butantan, Av. Vital Brasil, 1500 05503-900 São Paulo, SP, Brazil
| | - Gandhi Rádis-Baptista
- Labomar-Instituto de Ciências do Mar, Universidade Federal do Ceará, Fortaleza, CE, Brazil
| | - Alexandre Kerkis
- Laboratório de Genética, Instituto Butantan, Av. Vital Brasil, 1500 05503-900 São Paulo, SP, Brazil
| | - Tetsuo Yamane
- Universidade Estadual da Amazônia (UEA) e Laboratório de Bioquímica e Biologia Molecular, Centro de Biotecnologia da Amazônia (CBA), Manaus, AM, Brazil
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Pinthong K, Tanomtong A, Getlekha N, Sangpadee W, Sangpakdee K, Sanoamuang LO. First Cytogenetic Study of Puff-Faced Water Snake, Homalopsis buccata (Squamata, Colubridae) by Conventional Staining, Ag-NOR Banding and GTG-Banding Techniques. CYTOLOGIA 2013. [DOI: 10.1508/cytologia.78.141] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Affiliation(s)
- Krit Pinthong
- Biology Program, Faculty of Science and Technology, Surindra Rajabhat University
| | - Alongklod Tanomtong
- Applied Taxonomic Research Center (ATRC), Department of Biology, Faculty of Science, Khon Kaen University
| | - Nuntaporn Getlekha
- Applied Taxonomic Research Center (ATRC), Department of Biology, Faculty of Science, Khon Kaen University
| | - Wiwat Sangpadee
- Biology Program, Faculty of Science, Udon-Thani Rajabhat University
| | | | - La-orsri Sanoamuang
- Applied Taxonomic Research Center (ATRC), Department of Biology, Faculty of Science, Khon Kaen University
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Matsubara K, Kuraku S, Tarui H, Nishimura O, Nishida C, Agata K, Kumazawa Y, Matsuda Y. Intra-genomic GC heterogeneity in sauropsids: evolutionary insights from cDNA mapping and GC(3) profiling in snake. BMC Genomics 2012; 13:604. [PMID: 23140509 PMCID: PMC3549455 DOI: 10.1186/1471-2164-13-604] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2012] [Accepted: 10/24/2012] [Indexed: 12/19/2022] Open
Abstract
BACKGROUND Extant sauropsids (reptiles and birds) are divided into two major lineages, the lineage of Testudines (turtles) and Archosauria (crocodilians and birds) and the lineage of Lepidosauria (tuatara, lizards, worm lizards and snakes). Karyotypes of these sauropsidan groups generally consist of macrochromosomes and microchromosomes. In chicken, microchromosomes exhibit a higher GC-content than macrochromosomes. To examine the pattern of intra-genomic GC heterogeneity in lepidosaurian genomes, we constructed a cytogenetic map of the Japanese four-striped rat snake (Elaphe quadrivirgata) with 183 cDNA clones by fluorescence in situ hybridization, and examined the correlation between the GC-content of exonic third codon positions (GC3) of the genes and the size of chromosomes on which the genes were localized. RESULTS Although GC3 distribution of snake genes was relatively homogeneous compared with those of the other amniotes, microchromosomal genes showed significantly higher GC3 than macrochromosomal genes as in chicken. Our snake cytogenetic map also identified several conserved segments between the snake macrochromosomes and the chicken microchromosomes. Cross-species comparisons revealed that GC3 of most snake orthologs in such macrochromosomal segments were GC-poor (GC3 < 50%) whereas those of chicken orthologs in microchromosomes were relatively GC-rich (GC3 ≥ 50%). CONCLUSION Our results suggest that the chromosome size-dependent GC heterogeneity had already occurred before the lepidosaur-archosaur split, 275 million years ago. This character was probably present in the common ancestor of lepidosaurs and but lost in the lineage leading to Anolis during the diversification of lepidosaurs. We also identified several genes whose GC-content might have been influenced by the size of the chromosomes on which they were harbored over the course of sauropsid evolution.
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Affiliation(s)
- Kazumi Matsubara
- Department of Information and Biological Sciences, Graduate School of Natural Sciences, Nagoya City University, 1 Yamanohata, Mizuho-cho, Mizuho-ku, Nagoya, Aichi 467-8501, Japan.
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Non-homologous sex chromosomes of birds and snakes share repetitive sequences. Chromosome Res 2010; 18:787-800. [DOI: 10.1007/s10577-010-9152-9] [Citation(s) in RCA: 72] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2010] [Revised: 08/04/2010] [Accepted: 08/04/2010] [Indexed: 11/26/2022]
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The ZW sex microchromosomes of an Australian dragon lizard share no homology with those of other reptiles or birds. Chromosome Res 2009; 17:965-73. [PMID: 19967443 DOI: 10.1007/s10577-009-9102-6] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2009] [Revised: 09/30/2009] [Accepted: 10/07/2009] [Indexed: 10/20/2022]
Abstract
Reptiles show a diverse array of sex chromosomal systems but, remarkably, the Z sex chromosomes of chicken are homologous to the ZW sex chromosomes of a species of gecko, Gekko hokouensis, suggesting an ancient but common origin. This is in contrast to the ZW sex chromosomes of snakes and a species of soft-shelled turtle, Pelodiscus sinensis, which are nonhomologous to those of chicken or each other and appear to have been independently derived. In this paper, we determine what homology, if any, the sex chromosomes of the Australian dragon lizard Pogona vitticeps shares with those of snake and chicken by mapping the dragon homologs of five snake Z chromosome genes (WAC, KLF6, TAX1BP1, RAB5A, and CTNNB1) and five chicken Z chromosome genes (ATP5A1, GHR, DMRT1, CHD1, and APTX) to chromosomes in the dragon. The dragon homologs of snake and chicken sex chromosome genes map to chromosomes 6 and chromosome 2, respectively, in the dragon and that DMRT1, the bird sex-determining gene, is not located on the sex chromosomes of P. vitticeps. Indeed, our data show that the dragon homolog to the chicken Z chromosome is likely to be wholly contained within chromosome 2 in P. vitticeps, which suggests that the sex-determining factor in P. vitticeps is not the sex-determining gene of chicken. Homology between chicken Z chromosome and G. hokouensis ZW chromosome pairs has been interpreted as retention of ancient ZW sex chromosomes in which case the nonhomologous sex chromosomes of snake and dragons would be independently derived. Our data add another case of independently derived sex chromosomes in a squamate reptile, which makes retention of ancient sex chromosome homology in the squamates less plausible. Alternatively, the conservation between the bird Z chromosome and the G. hokouensis ZW chromosomes pairs is coincidental, may be an example of convergent evolution, its status as the Z chromosome having been independently derived in birds and G. hokouensis.
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Karyotypic evolution in squamate reptiles: comparative gene mapping revealed highly conserved linkage homology between the butterfly lizard (Leiolepis reevesii rubritaeniata, Agamidae, Lacertilia) and the Japanese four-striped rat snake (Elaphe quadrivirgata, Colubridae, Serpentes). Chromosome Res 2009; 17:975-86. [PMID: 19937109 DOI: 10.1007/s10577-009-9101-7] [Citation(s) in RCA: 52] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2009] [Accepted: 11/01/2009] [Indexed: 10/20/2022]
Abstract
The butterfly lizard (Leiolepis reevesii rubritaeniata) has the diploid chromosome number of 2n = 36, comprising two distinctive components, macrochromosomes and microchromosomes. To clarify the conserved linkage homology between lizard and snake chromosomes and to delineate the process of karyotypic evolution in Squamata, we constructed a cytogenetic map of L. reevesii rubritaeniata with 54 functional genes and compared it with that of the Japanese four-striped rat snake (E. quadrivirgata, 2n = 36). Six pairs of the lizard macrochromosomes were homologous to eight pairs of the snake macrochromosomes. The lizard chromosomes 1, 2, 4, and 6 corresponded to the snake chromosomes 1, 2, 3, and Z, respectively. LRE3p and LRE3q showed the homology with EQU5 and EQU4, respectively, and LRE5p and LRE5q corresponded to EQU7 and EQU6, respectively. These results suggest that the genetic linkages have been highly conserved between the two species and that their karyotypic difference might be caused by the telomere-to-telomere fusion events followed by inactivation of one of two centromeres on the derived dicentric chromosomes in the lineage of L. reevesii rubritaeniata or the centric fission events of the bi-armed macrochromosomes and subsequent centromere repositioning in the lineage of E. quadrivirgata. The homology with L. reevesii rubritaeniata microchromosomes were also identified in the distal regions of EQU1p and 1q, indicating the occurrence of telomere-to-telomere fusions of microchromosomes to the p and q arms of EQU1.
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Quinn AE, Ezaz T, Sarre SD, Graves JAM, Georges A. Extension, single-locus conversion and physical mapping of sex chromosome sequences identify the Z microchromosome and pseudo-autosomal region in a dragon lizard, Pogona vitticeps. Heredity (Edinb) 2009; 104:410-7. [DOI: 10.1038/hdy.2009.133] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
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The ZW sex chromosomes of Gekko hokouensis (Gekkonidae, Squamata) represent highly conserved homology with those of avian species. Chromosoma 2008; 118:43-51. [DOI: 10.1007/s00412-008-0176-2] [Citation(s) in RCA: 80] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2008] [Revised: 06/11/2008] [Accepted: 07/16/2008] [Indexed: 12/31/2022]
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Ananias F, Modesto ADS, Mendes SC, Napoli MF. Unusual primitive heteromorphic ZZ/ZW sex chromosomes in Proceratophrys boiei (Anura, Cycloramphidae, Alsodinae), with description of C-Band interpopulational polymorphism. Hereditas 2007; 144:206-12. [PMID: 18031355 DOI: 10.1111/j.2007.0018-0661.02026.x] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
Abstract
We performed cytogenetic analyses on specimens from three population samples of Proceratophrys boiei from southeastern and northeastern Brazil. We stained chromosomes of mitotic and meiotic cells with Giemsa, C-banding and Ag-NOR methods. All specimens of P. boiei presented a karyotype with a full chromosome complement of 2n=22, metacentric and submetacentric. We observed the secondary constriction within the short arm of pair 8, which was in the same position of the nucleolus organizer region (NOR). NOR heteromorphism was observed within two specimens from the municipality of Mata de São João (northeastern Bahia State). The C-banding evidenced an unusual heterochromatic pattern in the genome of P. boiei. In the southern most population samples (São Paulo State), we observed large blocks of heterochromatin in the centromeric regions of all chromosomes, whereas the northernmost samples (Bahia State) presented a small amount of constitutive heterochromatin. We suppose that this geographic variation in heterochromatin quantities could be due to heterochromatinization of some chromosome regions in the genome of the São Paulo samples. Furthermore, females from São Paulo presented, within chromosome pair 1 from C-banded karyotypes, one homologous chromosome almost heterochromatic, whereas males had heterochromatin restricted to the centromeric region. This unusual heterochromatic arrangement led us to assume that P. boiei owns a ZZ/ZW type of sexual determination system. This finding is very important, as this is the first record of ZZ/ZW sex chromosomes within Cycloramphidae. We believe that the cytogenetic differences found between southeastern and northeastern Brazilian population samples of P. boiei strongly supports the existence of a species complex under the name P. boiei, and the requirement of taxonomic and systematic reviews by morphological, bioacoustical, molecular, and cytogenetic data could define this taxonomic issue in the future.
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Affiliation(s)
- Fernando Ananias
- Curso de Ciências Biológicas, Universidade São Francisco (USF), Bragança Paulista, São Paulo, Brazil.
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Kawai A, Nishida-Umehara C, Ishijima J, Tsuda Y, Ota H, Matsuda Y. Different origins of bird and reptile sex chromosomes inferred from comparative mapping of chicken Z-linked genes. Cytogenet Genome Res 2007; 117:92-102. [PMID: 17675849 DOI: 10.1159/000103169] [Citation(s) in RCA: 100] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2006] [Accepted: 11/16/2006] [Indexed: 11/19/2022] Open
Abstract
Recent progress of chicken genome projects has revealed that bird ZW and mammalian XY sex chromosomes were derived from different autosomal pairs of the common ancestor; however, the evolutionary relationship between bird and reptilian sex chromosomes is still unclear. The Chinese soft-shelled turtle (Pelodiscus sinensis) exhibits genetic sex determination, but no distinguishable (heteromorphic) sex chromosomes have been identified. In order to investigate this further, we performed molecular cytogenetic analyses of this species, and thereby identified ZZ/ZW-type micro-sex chromosomes. In addition, we cloned reptile homologues of chicken Z-linked genes from three reptilian species, the Chinese soft-shelled turtle and the Japanese four-striped rat snake (Elaphe quadrivirgata), which have heteromorphic sex chromosomes, and the Siam crocodile (Crocodylus siamensis), which exhibits temperature-dependent sex determination and lacks sex chromosomes. We then mapped them to chromosomes of each species using FISH. The linkage of the genes has been highly conserved in all species: the chicken Z chromosome corresponded to the turtle chromosome 6q, snake chromosome 2p and crocodile chromosome 3. The order of the genes was identical among the three species. The absence of homology between the bird Z chromosome and the snake and turtle Z sex chromosomes suggests that the origin of the sex chromosomes and the causative genes of sex determination are different between birds and reptiles.
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Affiliation(s)
- A Kawai
- Laboratory of Animal Cytogenetics, Division of Biosciences, Graduate School of Science, Hokkaido University, Sapporo, Japan
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Matsubara K, Tarui H, Toriba M, Yamada K, Nishida-Umehara C, Agata K, Matsuda Y. Evidence for different origin of sex chromosomes in snakes, birds, and mammals and step-wise differentiation of snake sex chromosomes. Proc Natl Acad Sci U S A 2006; 103:18190-5. [PMID: 17110446 PMCID: PMC1838728 DOI: 10.1073/pnas.0605274103] [Citation(s) in RCA: 210] [Impact Index Per Article: 11.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Revised: 06/23/2006] [Indexed: 11/18/2022] Open
Abstract
All snake species exhibit genetic sex determination with the ZZ/ZW type of sex chromosomes. To investigate the origin and evolution of snake sex chromosomes, we constructed, by FISH, a cytogenetic map of the Japanese four-striped rat snake (Elaphe quadrivirgata) with 109 cDNA clones. Eleven of the 109 clones were localized to the Z chromosome. All human and chicken homologues of the snake Z-linked genes were located on autosomes, suggesting that the sex chromosomes of snakes, mammals, and birds were all derived from different autosomal pairs of the common ancestor. We mapped the 11 Z-linked genes of E. quadrivirgata to chromosomes of two other species, the Burmese python (Python molurus bivittatus) and the habu (Trimeresurus flavoviridis), to investigate the process of W chromosome differentiation. All and 3 of the 11 clones were localized to both the Z and W chromosomes in P. molurus and E. quadrivirgata, respectively, whereas no cDNA clones were mapped to the W chromosome in T. flavoviridis. Comparative mapping revealed that the sex chromosomes are only slightly differentiated in P. molurus, whereas they are fully differentiated in T. flavoviridis, and E. quadrivirgata is at a transitional stage of sex-chromosome differentiation. The differentiation of sex chromosomes was probably initiated from the distal region on the short arm of the protosex chromosome of the common ancestor, and then deletion and heterochromatization progressed on the sex-specific chromosome from the phylogenetically primitive boids to the more advanced viperids.
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Affiliation(s)
- Kazumi Matsubara
- *Laboratory of Animal Cytogenetics, Department of Genome Dynamics, Creative Research Initiative “Sousei” and
| | - Hiroshi Tarui
- Genome Resource and Analysis Subunit, RIKEN Center for Developmental Biology, 2-2-3 Minatojima-minamimachi, Chuo-ku, Kobe 650-0047, Japan
| | - Michihisa Toriba
- Japan Snake Institute, 3318 Yabuzuka-cho, Ota 379-2301, Japan; and
| | - Kazuhiko Yamada
- *Laboratory of Animal Cytogenetics, Department of Genome Dynamics, Creative Research Initiative “Sousei” and
| | - Chizuko Nishida-Umehara
- *Laboratory of Animal Cytogenetics, Department of Genome Dynamics, Creative Research Initiative “Sousei” and
- Laboratory of Animal Cytogenetics, Division of Life Science, Graduate School of Life Science, Hokkaido University, North 10 West 8, Kita-ku, Sapporo 060-0810, Japan
| | - Kiyokazu Agata
- Department of Biophysics, Graduate School of Science, Kyoto University, Kitashirakawa-Oiwake, Sakyo-ku, Kyoto 606-8502, Japan
| | - Yoichi Matsuda
- *Laboratory of Animal Cytogenetics, Department of Genome Dynamics, Creative Research Initiative “Sousei” and
- Laboratory of Animal Cytogenetics, Division of Life Science, Graduate School of Life Science, Hokkaido University, North 10 West 8, Kita-ku, Sapporo 060-0810, Japan
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Wolf U, Schempp W, Scherer G. Molecular biology of the human Y chromosome. Rev Physiol Biochem Pharmacol 2005; 121:147-213. [PMID: 1485072 DOI: 10.1007/bfb0033195] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Affiliation(s)
- U Wolf
- Institut für Humangenetik und Anthropologie der Universität, Freiburg, FRG
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Matsuda Y, Nishida-Umehara C, Tarui H, Kuroiwa A, Yamada K, Isobe T, Ando J, Fujiwara A, Hirao Y, Nishimura O, Ishijima J, Hayashi A, Saito T, Murakami T, Murakami Y, Kuratani S, Agata K. Highly conserved linkage homology between birds and turtles: bird and turtle chromosomes are precise counterparts of each other. Chromosome Res 2005; 13:601-15. [PMID: 16170625 DOI: 10.1007/s10577-005-0986-5] [Citation(s) in RCA: 95] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2005] [Accepted: 06/09/2005] [Indexed: 11/24/2022]
Abstract
The karyotypes of birds, turtles and snakes are characterized by two distinct chromosomal components, macrochromosomes and microchromosomes. This close karyological relationship between birds and reptiles has long been a topic of speculation among cytogeneticists and evolutionary biologists; however, there is scarcely any evidence for orthology at the molecular level. To define the conserved chromosome synteny among humans, chickens and reptiles and the process of genome evolution in the amniotes, we constructed comparative cytogenetic maps of the Chinese soft-shelled turtle (Pelodiscus sinensis) and the Japanese four-striped rat snake (Elaphe quadrivirgata) using cDNA clones of reptile functional genes. Homology between the turtle and chicken chromosomes is highly conserved, with the six largest chromosomes being almost equivalent to each other. On the other hand, homology to chicken chromosomes is lower in the snake than in the turtle. Turtle chromosome 6q and snake chromosome 2p represent conserved synteny with the chicken Z chromosome. These results suggest that the avian and turtle genomes have been well conserved during the evolution of the Arcosauria. The avian and snake sex Z chromosomes were derived from different autosomes in a common ancestor, indicating that the causative genes of sex determination may be different between birds and snakes.
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Affiliation(s)
- Yoichi Matsuda
- Laboratory of Animal Cytogenetics, Division of Genome Dynamics, Creative Research Initiative "Sousei", Hokkaido University, North 10 West 8, Kita-ku, Sapporo 060-0810, Japan.
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Ueno K, Ota K, Kobayashi T. Heteromorphic sex chromosomes of lizardfish (Synodontidae): focus on the ZZ-ZW1W2 system in Trachinocephalus myops. Genetica 2002; 111:133-42. [PMID: 11841162 DOI: 10.1023/a:1013749027620] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
The karyotype and DNA content of four lizardfish species (family Synodontidae), that is, Saurida elongata, Synodus ulae, Synodus hoshinonis and Trachinocephalus myops, were analyzed. The karyotype of T. myops significantly differed from that of the other three species having diploid chromosome number of 48 with mainly acrocentric chromosomes and the ZZ-ZW sex chromosome system. The chromosome number of male T. myops was 2n = 26, while that of female T. myops was 2n = 27. The karyotype consisted of 11 pairs of metacentrics, one pair of acrocentrics and, in addition, two large metacentrics in the male and a single large metacentric, a distinctly small subtelocentric and a microchromosome in the female. C-banding demonstrated that in the female the subtelocentric chromosome and the microchromosome were heterochromatic. The karyotype of T. myops was thought to be derived from a 48 chromosome type synodontid fish through the involvement of Robertsonian rearrangement; the rearrangement of the sex chromosomes proceeded during karyotype evolution. Among the chromosomes, the large metacentrics were determined to be neo-Z (a fusion of the original Z and an autosome), the microchromosomes the W1 (originally W), and the subtelocentric chromosomes the W2 (derived from an autosome pair). The miniaturization of W1 and W2 chromosomes and their heterochromatinization suggested that sex chromosomes in this species have been already highly differentiated. The findings on DNA content implied that the karyotype of T. myops evolved by centric fusion events without loss in DNA amount.
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Affiliation(s)
- K Ueno
- Department of Fisheries, Faculty of Agriculture, Kinki University, Nara, Japan.
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Schmid M, Steinlein C. Sex chromosomes, sex-linked genes, and sex determination in the vertebrate class amphibia. EXS 2001:143-76. [PMID: 11301597 DOI: 10.1007/978-3-0348-7781-7_8] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
In this chapter the different categories of homomorphic and heteromorphic sex chromosomes, types of sex-determining mechanisms, known sex-linked genes, and data about sex-determining genes in the Amphibia have been compiled. Thorough cytogenetic analyses have shown that both XY/XX and ZW/ZZ sex chromosomes exist in the order Anura and Urodela. In some species quite unusual systems of sex determination have evolved (e.g. 0W-females/00-males or the co-existence of XY/XX and ZW/ZZ sex chromosomes within the same species). In the third order of the Amphibia, the Gymnophiona (or Apoda) there is still no information regarding any aspect of sex determination. Whereas most species of Anura and Urodela present undifferentiated, homomorphic sex chromosomes, there is also a considerable number of species in which an increasing structural complexity of the Y and W chromosomes exists. In various cases, the morphological differentiation of the sex chromosomes occurred as a result of quantitative and/or qualitative changes to the repetitive DNA sequences in the constitutive heterochromatin of the Y and W chromosomes. The greater the structural differences between the sex chromosomes, the lesser the extent of pairing in meiosis. No dosage compensation of the sex-linked genes in the somatic cells of the homogametic (XX or ZZ) individuals have been detected. The genes located to date on the amphibian sex chromosomes lead to the conclusion that there is no common ancestral or conserved sex-linkage group. In all amphibians, genetic sex determination (GSD) seems to operate, although environmental factors may influence sex determination and differentiation. Despite the accumulated evidence that GSD is operating in Anura and Urodela, there is little substantial information about how it functions. Although several DNA sequences homologous to the mammalian ZFY, SRY and SOX genes have been detected in the Anura or Urodela, none of these genes is an appropriate candidate to explain sex determination in these vertebrates.
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Affiliation(s)
- M Schmid
- Department of Human Genetics, University of Würzburg, Biozentrum, Am Hubland, D-97074 Würzburg, Germany
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Pigozzi MI, Solari AJ. The ZW pairs of two paleognath birds from two orders show transitional stages of sex chromosome differentiation. Chromosome Res 1999; 7:541-51. [PMID: 10598569 DOI: 10.1023/a:1009241528994] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
Pachytene oocytes from the two presumably most primitive orders (Paleognathae) among living birds were used to study the pairing behaviour and location of recombination nodules (RNs) in the sex pair. In the ratite Pterocnemia pennata (Rheiformes), the 42 analyzed ZW pairs show an average of 2.2 RNs distributed along 80% of the synaptonemal complex (SC) that covers the long arm of the acrocentric Z and W chromosomes in this homomorphic sex pair. In the tinamid Rynchotus rufescens (Tinamiformes), the 60 analyzed ZW pairs show an average of 1.35 RNs distributed along 66% of the SC covering most of the long arms of this visibly heteromorphic ZW pair. RNs are non-randomly distributed and show interference in both species, but in the tinamou they are restricted to a significantly smaller stretch. The discovery of an intermediate degree in the restriction of RN location, between the extremes of free recombination along most of the W in ratites and strict localization of a single RN in Neognath birds, suggests its relationship with the mechanism of sex chromosome differentiation among Aves.
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Affiliation(s)
- M I Pigozzi
- Centro de Investigaciones en Reproduccion, Facultad de Medicina, Buenos Aires, Argentina
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Ogawa A, Murata K, Mizuno S. The location of Z- and W-linked marker genes and sequence on the homomorphic sex chromosomes of the ostrich and the emu. Proc Natl Acad Sci U S A 1998; 95:4415-8. [PMID: 9539751 PMCID: PMC22503 DOI: 10.1073/pnas.95.8.4415] [Citation(s) in RCA: 82] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/1997] [Accepted: 02/09/1998] [Indexed: 02/07/2023] Open
Abstract
Perhaps the most striking fact about early Cenozoic avian history some 70 million years ago was the rapid radiation of large, flightless, ground-living birds. It has been suggested that, for a time, there was active competition between these large terrestrial birds and the early mammals. Probably reflecting the above noted early start of Ratitae of the infraclass Eoaves, the presumptive sex chromosomes of their present day survivors, such as the emu and the ostrich, largely remained homomorphic. The signs of genetic differentiation between their still-homomorphic Z and W chromosomes were tested by using two marker genes (Z-linked ZOV3 and the gene for the iron-responsive element-binding protein) and one marker sequence of a part of a presumptive pseudogene (W-linked EE0.6 of the chicken). Their homologues, maintaining 71-92% identities to the chicken counterparts, were found in both the emu (Dromaius novaehollandiae) and the ostrich (Struthio camelus). Their locations were visualized on chromosome preparations by fluorescence in situ hybridization. In the case of the emu, these three marker sequences were localized on both members of the fifth pair of a female, thus revealing no sign yet of genetic differentiation between the Z and the W. The finding was the same with regard to both members of the fourth pair of male ostriches. In the female ostrich, however, the sequence of the gene for the iron-responsive element-binding protein was missing from one of the pairs, thus revealing the differentiation by a small deletion of the W from the Z.
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Affiliation(s)
- A Ogawa
- Laboratory of Molecular Biology, Department of Applied Biological Chemistry, Faculty of Agriculture, Tohoku University, 1-1 Tsutsumidori-Amamiyamachi, Aoba-ku, Sendai 981 Japan
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Ribeiro-Paes JT, Rodrigues V. Sex determination and female reproductive development in the genus Schistosoma: a review. Rev Inst Med Trop Sao Paulo 1997; 39:337-44. [PMID: 9674285 DOI: 10.1590/s0036-46651997000600006] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023] Open
Abstract
Parasites of the genus Schistosoma were among the first metazoans to develop separate sexes, which is chromosomally determined in the fertilized egg. Despite the occurrence of specific sex chromosomes, the females of most Schistosomatidae species do not complete their somatic development and reach no sexual maturity without the presence of males. Indeed, the most controversial and at the same time most fascinating aspect about the sexual development of Schistosoma females lies on discover the nature of the stimulus produced by males that triggers and controls this process. Although the nature of the stimulus (physical or chemical) is a source of controversy, there is agreement that mating is a necessary requirement for maturation to occur and for migration of the female to a definitive final site of residence in the vascular system of the vertebrate host. It has also been proposed that the stimulus is not species-specific and, in some cases, not even genus-specific. Despite a vast literature on the subject, the process or processes underlying the meeting of males and females in the circulatory system have not been determined and as yet no consensus exists about the nature of the stimulus that triggers and maintains female development. In the studies about their role, Schistosoma males have been considered, at times pejoratively, the brother, the muscles or even the liver of females. Indeed, it still remains to be determined whether the stimulus responsible for female maturation involves the transfer of hormones, nutrients, neuromediators, mere tactile stimulation or a combination of chemotactic and thigmotactic factors.
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Affiliation(s)
- J T Ribeiro-Paes
- Departamento de Ciências Biológicas, Faculdade de Filosofia, Ciências e Letras, UNESP (Campus de Assis), Brasil.
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Pigozzi MI, Solari AJ. Extreme axial equalization and wide distribution of recombination nodules in the primitive ZW pair of Rhea americana (Aves, Ratitae). Chromosome Res 1997; 5:421-8. [PMID: 9364944 DOI: 10.1023/a:1018404610973] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
Pachytene oocytes from the ratite bird Rhea americana were used for synaptonemal complex analysis with a surface spreading technique and phosphotungstic acid staining. The ZW bivalent is slightly smaller than the fourth autosomal bivalent and clearly shows unequal W and Z axes only in 27% of the bivalents. Most of the ZW pairs are completely adjusted and thus the W and Z axes are almost equal in length. A sample of 134 recombination nodules (RNs) from 63 ZW pairs showed a striking departure of number and location of these nodules compared with those of carinate birds. The average number of RNs in the ZW pair of R. americana is 2.13, and the average SC length per RN is 4.2 microm. The locations of the RNs along most of the long arms of the Z and W are not random, and the distances between pairs of RNs show interference. Thus, the pattern of RNs in this mostly euchromatic ZW pair is identical to that of autosomes. From the present and previous data, it is concluded that the ZW pair of R. americana is in a primitive stage of chromosomal differentiation, in which recombination is restricted only in the small short arm and in the pericentromeric region.
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Affiliation(s)
- M I Pigozzi
- Centro de Investigaciones en Reproduccion, Facultad de Medicina, Buenos Aires, Argentina
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Haaf T, Schmid M. An early stage of ZW/ZZ sex chromosome differentiation in Poecilia sphenops var. melanistica (Poeciliidae, Cyprinodontiformes). Chromosoma 1984. [DOI: 10.1007/bf00302348] [Citation(s) in RCA: 49] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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Schmid M, Haaf T, Geile B, Sims S. Chromosome banding in Amphibia. VIII. An unusual XY/XX-sex chromosome system in Gastrotheca riobambae (Anura, Hylidae). Chromosoma 1983; 88:69-82. [PMID: 6192977 DOI: 10.1007/bf00329505] [Citation(s) in RCA: 72] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
The mitotic and meiotic chromosomes of the marsupial frog Gastrotheca riobambae were analysed with various banding techniques. The karyotype of this species is distinguished by considerable amounts of constitutive heterochromatin and unusual, heteromorphic XY sex chromosomes. The Y chromosome is considerably larger than the X chromosome and almost completely heterochromatic. The analysis of the banding patterns obtained with GC- and AT-base-pair-specific fluorochromes shows that the constitutive heterochromatin in the Y chromosome consists of at least three different structural categories. The only nucleolus organizer region (NOR) of the karyotype is localized in the short arm of the X chromosome. This causes a sex-specific difference in the number of NOR: female animals have two NORs in diploid cells, male animals one. No cytological indications were found for the inactivation of one of the two X chromosomes in the female cells. In male meiosis, the heteromorphic sex chromosomes form a characteristic sex-bivalent by pairing their telomeres in an end-to-end arrangement. The significance of the XY/XX sex chromosomes of G. riobambae for the study of X-linked genes in Amphibia, the evolution of sex chromosomes and their specific DNA sequences, and the significance of the meiotic process of sex chromosomes are discussed.
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Abstract
A family of DNA sequences which appears to be limited to eukaryotes is concentrated on the sex-determining chromosomes of species as widely separated evolutionarily as snakes and mammals. The significance of this distribution is presently seen in terms of the function of these sequences in cycles of chromosome condensation and decondensation involved in the control of gene expression. Thus, their concentration on the sex chromosomes is interpreted in the context of the evolution of such chromosomes which, it is hypothesised, involves the superimposition of the controls of the dominant sex-determining gene(s) upon the entire linkage group. This would result in the prevention of the large majority of its genes from having effects upon the phenotype and, in consequence, lead to their mutation to functionlessness at the maximum rate.
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Affiliation(s)
- K W Jones
- Institute of Animal Genetics, University of Edinburgh, Scotland, U.K
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48
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Affiliation(s)
- M Schmid
- Institut für Humangenetik, University of Würzburg, Federal Republic of Germany
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49
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Grossman AI, Short RB, Cain GD. Karyotype evolution and sex chromosome differentiation in Schistosomes (Trematoda, Schistosomatidae). Chromosoma 1981; 84:413-30. [PMID: 7327052 DOI: 10.1007/bf00286030] [Citation(s) in RCA: 58] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Abstract
The morphology of C-banded metaphase chromosomes has been studied in two hermaphroditic and ten gonochoristic digenetic trematodes (schistosomes). Comparison of numbers and morphology of chromosomes indicates that the karyotype of primitive trematodes probably was composed of 10 (or 11) pairs of telocentric or subtelocentric chromosomes, and reduction of chromosome numbers in advanced species resulted from centromeric fusion rather than elimination of chromosomes. Observation of heteromorphic chromosomes in a hermaphroditic trematode (Spirorchis) suggested a differentiation of "pre-sex" chromosomes in species ancestral to dioecious trematodes which possess distinctly differentiated sex chromosomes. Our results indicate that differentiation of Z and W chromosomes in the gonochoristic trematodes resulted from: (a) partial constitutive heterochromatinization of the W chromosome (Schistosoma mansoni and S. haematobium complexes, African schistosomes), (b) deletion of part of the W (S. japonicum and S. mekongi, Asian schistosomes), and (c) translocation of part of one sex chromosome onto another (Schistosomatium douthitti and Heterobilharzia americana, American schistosomes) with subsequent heterochromatinization of the W in H. americana.
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