Chromosomal Mapping of Repetitive DNAs in Characidium (Teleostei, Characiformes): Genomic Organization and Diversification of ZW Sex Chromosomes.

摘要: The speciose neotropical genus Characidium has proven to be a good model for cytogenetic exploration. Representatives of this often have conserved diploid chromosome number; some species exhibit highly differentiated ZZ/ZW sex system, while others do not show any sex-related heteromorphism. In study, painting using W-specific probe and comparative mapping repetitive sequences, including ribosomal clusters 4 microsatellite motifs - (CA)15, (GA)15, (CG)15, (TTA)10 -, were performed in 6 species, 5 which possessed heteromorphic ZW system. showed hybridization signals on the W all analyzed indicating homology among chromosomes. Remarkably, single major rDNA-bearing pair was found species. 18S rDNA localized chromosomes C. lanei, timbuiense pterostictum, one autosome vidali gomesi. contrast, number 5S varied. Notably, minor identified vidali. Microsatellites widely distributed across almost karyotypes, with greater accumulation subtelomeric regions. However, clear differences abundance each motif detected addition, Z differential distinct motifs. Our results revealed variability distribution DNA sequences their possible association diversification