Genes opsins em ciclídeos neotropicais e sua relevância para estudos em planícies de inundação.

Abstract

The Cichlidae family comprises a major freshwater fish group used for evolutionary studies due to its rapid radiation and speciation. It has a great diversity of coloration, and it is one of its characteristics used to differentiate species which shows distinct coloring patterns. In addition, floodplains have a great habitats heterogeneity and consequently great light heterogeneity too. Thus, the way light is perceived by these organisms should be considered. Also the different light wavelengths absorbed by visual pigments that are expressed by the opsins gene, and among them, LWS which is the most variable one. This study aimed to compare nucleotide and amino acids sequences from regions of the opsin gene LWS that modulate the spectral and non spectral properties of the opsin protein LWS of species of the genus Cichla and Crenicichla, as well the comparison of obtained sequences with a African cichlids group. It also aimed to show the relevance of studies with genes of this family in neotropical cichlids and in floodplains. Cichla kelberi, Cichla piquiti and Cichla monoculus were collected in Tocantins-Araguaia basin, São Francisco River, Solimões River and in the upper Paraná River, which also provided Crenicichla britskii samples.The presence of intraspecific and interspecific polymorphisms for the species of genus Cichla, and a large number of polymorphisms between the two studied genus were verified. The data indicate a probable convergence of this gene in Crenicichla. In addition, the polymorphic regions of neotropical and African groups do not overlap, becoming an indication that they are under different evolutionary pressure. Also, floodplains could be considered as natural experiments, mostly in studies related to the opsin genes expression.