Análise da variabilidade genética de Prochilodus spp. (Prochilodontidae) das bacias dos rios Paraopeba, Pará, e Grande, utilizando marcador decomplexas repetições hipervariáveis

Abstract

In the last decades, many rivers have been dammed for the construction of reservoirs. Dams cause significant adverse impact on the population of local fish. Besides the flood regime changes and blocking of migratory routes of migratory fishes, one of the consequences of the construction of dams is the isolation of native populations, which can lead to effects such as the loss of genetic variability and endogamic depression. This can reduce the fitness and increase the risk of local extinction of the species. Thus, it is of huge relevance the accomplishment of populational studies in species which habitat has been fragmented as a result of dam building. Because of their high level of polymorphism, molecular markers have been largely used in populational analysis of many species of fish, in order to evaluate the genetic structure and variability of populations and the impact of the dams and the hatchery fish have on wild populations. The objective of this study was to characterize the genetic diversity and population structure of three fish species of the genus Prochilodus (P. costatus, P. argenteus e P. lineatus) in three River Basins of the stateof Minas Gerais: Para, Paraopeba e Grande which in recent decades have been changed by the construction of several dams. From 71 clones previously isolated by our group from a genomic libraw of Prochi/odus Iineatus, 8 were selected and the best PCR conditions achieved. In addition, the complex hypervariable repeat 2V35 was tested in 252 individuals of Prochi/odus spp collected in the three Basins mentionedabove. Its usefulness in population genetic studies was evaluated by analyzing indices of molecular diversity, molecular variance (AMOVA), isolation by distance besides filogenetics analyses. Only one haplotype was shared by the three species (Hap 1) proving the high level of discrimination by the marker for intra-specific analyzes. Fish from the three rivers showed high levels of gene diversity and significant differentiation was detected, suggesting that populations from the three sites were affected by the fragmentation of the River and the hatchery activity. Our study showed to be very helpful for the management and fish conservation in these areas.