Caracterização genética de invasões biológicas: o caso do Tucunaré (Cichla spp) em Minas Gerais.

Abstract

This study aimed to understand the colonization process of the Amazonian fish introduced in southeast Brazil using molecular markers. In the invasive biology studies, the unequivocal characterization of the source population and the invasive route, are vital information not only in the evaluation on its adaptative success in invaded areas but also in its management and control. Genetic analyses were carried out on the introduced populations at the major river basis in the Minas Gerais State (São Francisco, Grande, Paranaíba and Doce). DNA sequences of twomitochondrial regions from specimens of the introduced species were obtained and compared with the natives stocks from the Amazon basin in order to detect the source population. Only mtDNA haplotypes from the species C. piquiti and C. kelberi, endemic from the Araguaia-Tocantins, the eastern limit of the Amazon basin, were recovered in the introduced populations. Furthermore, ten (10) microsatellites loci were developed for the invasive species C. piquiti (successfully tested for C. kelberi) in order to analyze the genetic structure and diversity of the introduced populations. The results have shown a founder effect in the introduced populations, with reduction in the allelic richness and expected heterozigosity, when they were compared with the native population. TheBayesian analysis of attribution detected possible hybrids specimens only in the native population. The tucunaré, apart from its low genetic diversity, is well established in the invasive areas showing that the propagule effect is not an important matter in its invasive process. Genetic and geographic distribution patterns suggest that C. kelberi and C. piquiti showed different introductory process in the major river basins in the Minas Gerais State.