RESUMO
Recently renamed, Psalidodon scabripinnis populations of Serra da Mantiqueira, previously known as Astyanax scabripinnis have been deeply studied in the last years. These populations are small and isolated and occur very close to the watershed between Paraíba do Sul River basin and Upper Paraná River basin, in Serra da Mantiqueira region in the Atlantic Rainforest. These conditions arouse the interest in knowing theor genetic conservation status and how they responded to the separation between the two rivers basins. Therefore, we accessed the genetic diversity of five P. scabripinnis populations of this region with microsatellites and mitochondrial data. The results showed a complex structure pattern that doesn't match the simple basin separation and a reasonably conservation status when compared with other populations of the same family or with similar natural history.
RESUMO
Access the genetic variability of endangered and isolated populations has become an important conservation tool. Astyanax scabripinnis is a well-known fish model for genetic studies, forming very isolated populations in headwaters. Besides that, this species frequently presents supernumerary chromosomes, which elevates the interest on genetic studies. Genetic diversity of an Astyanax scabripinnispopulation from the Atlantic Forest (Serra da Mantiqueira region, Brazil) was assessed with microsatellite markers for the first time. Since microsatellite markers are not described for this species, we tested markers described for a related species for transferability to A. scabripinnis. Six polymorphic loci were sufficiently reliable for population genetic analysis. We found that this population passed through a recent bottleneck because of the presence of an excess of heterozygotes, low allelic diversity, heterozygosity excess, and small effective population size. Individuals with and without B chromosomes were previously identified in this population and our study found private alleles in the individuals without B chromosomes. Furthermore, when individuals without B chromosomes were removed from the analysis, the population did not present heterozygosity excess, suggesting that the bottleneck event was driven by individuals with B chromosomes. Our results provide an insight into the value of microsatellite markers as molecular tools and is the first genetic study using molecular data of A. scabripinnis from this area.
