Dataset Information

W Chromosome Dynamics in Triportheus Species (Characiformes, Triportheidae): An Ongoing Process Narrated by Repetitive Sequences.

ABSTRACT: Characterizing the abundance and genomic distribution of repetitive DNAs provides information on genome evolution, especially regarding the origin and differentiation of sex chromosomes. Triportheus fishes offer a useful model to explore the evolution of sex chromosomes, since they represent a monophyletic group in which all species share a ZZ/ZW sex chromosome system. In this study, we analyzed the distribution of 13 classes of repetitive DNA sequences by FISH, including microsatellites, rDNAs, and transposable elements in 6 Triportheus species, in order to investigate the fate of the sex-specific chromosome among them. These findings show the dynamic differentiation process of the W chromosome concerning changes in the repetitive DNA fraction of the heterochromatin. The differential accumulation of the same class of repeats on this chromosome, in both nearby and distant species, reflects the inherent dynamism of the microsatellites, as well as the plasticity that shapes the evolutionary history of the sex chromosomes, even among closely related species sharing a same sex chromosome system.

SUBMITTER: Yano CF

PROVIDER: S-EPMC4888443 | biostudies-literature | 2016 Jul

REPOSITORIES: biostudies-literature

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Publications

W Chromosome Dynamics in Triportheus Species (Characiformes, Triportheidae): An Ongoing Process Narrated by Repetitive Sequences.

Yano Cassia Fernanda CF Bertollo Luiz Antônio Carlos LA Liehr Thomas T Troy Waldo Pinheiro WP Cioffi Marcelo de Bello Mde B

The Journal of heredity 20160401 4

Characterizing the abundance and genomic distribution of repetitive DNAs provides information on genome evolution, especially regarding the origin and differentiation of sex chromosomes. Triportheus fishes offer a useful model to explore the evolution of sex chromosomes, since they represent a monophyletic group in which all species share a ZZ/ZW sex chromosome system. In this study, we analyzed the distribution of 13 classes of repetitive DNA sequences by FISH, including microsatellites, rDNAs, ...[more]

PMID: 27036509

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Project description:BackgroundThe 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.ResultsPartial 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.ConclusionOur 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.

Dataset Information

W Chromosome Dynamics in Triportheus Species (Characiformes, Triportheidae): An Ongoing Process Narrated by Repetitive Sequences.

Publications

W Chromosome Dynamics in Triportheus Species (Characiformes, Triportheidae): An Ongoing Process Narrated by Repetitive Sequences.

Similar Datasets

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