Tracking the evolutionary pathway of sex chromosomes among fishes: characterizing the unique XX/XY1Y2 system in Hoplias malabaricus (Teleostei, Characiformes)

摘要: The Neotropical fish, Hoplias malabaricus, is one of the most cytogenetically studied fish taxon with seven distinct karyomorphs (A–G) comprising varying degrees sex chromosome differentiation, ranging from homomorphic to highly differentiated simple and multiple chromosomes. Therefore, this offers a unique opportunity track evolutionary mechanisms standing behind evolution differentiation. Here, we focused on high-resolution cytogenetic characterization XX/XY1Y2 system found in its (G). For this, applied suite conventional (Giemsa-staining, C-banding) molecular approaches, including fluorescence situ hybridization FISH (with 5S 18S rDNAs, 10 microsatellite motifs telomeric (TTAGGG) n sequences as probes), comparative genomic (CGH), whole painting (WCP). In addition, performed analyses other Erythrinidae species discover origin karyomorph G-specific XY1Y2 system. WCP experiments confirmed homology between these chromosomes nascent XX/XY F, but disproved those A–D closely related species. Besides, putative such by rearrangements several pairs an ancestral karyotype was also highlighted. clear identification male-specific region Y1 suggested differential pattern repetitive accumulation. present data system, revealing evidences for high level plasticity differentiation within Erythrinidae.