Diversidade genética e padrões cromossômicos associados a quebras de barreira pós-zigóticas em peixes do gênero Chaetodon (Perciformes)

Abstract

Interspecific hybridization has been identified in various animal groups, among these, on a recurring basis in marine fish, notably in the Chaetodontidae family. The Chaetodon is the most diverse gender in the family, with about 30 species able to produce viable hybrids. All relevant features of this phenomenon have been analyzed, but we still need more data about the break of reproductive barriers in this genre. In the present study were compared sequences of the 12S gene, 16S, rag2 and NADH of Chaetodon genus with produce known hybrids, in order to ascertain what the genetic distance between them and cytogenetic comparisons by chromosomal mapping of regions of rDNA 18S and 5S of C. striatus, C. sedentarius and C. capistratus, from South Atlantic and Caribbean. The results indicate that parental species, even having a high level of genetic divergence, maintains the potential intercross and are capable to produce viable hybrids. An extreme conservatism karyotype inter- and intraspecific was observed for the species. Despite the long interval of separation between some species, interspecific reproductive potential as well an environmental and biological factors may have been favored by extensive karyotype homogeneity present in the family.