Molecular Characterization of Steindachnerina (Pisces, Characiformes) Populations from Upper Paraná River Floodable Areas

Abstract

Steindachnerina insculpta was the only species of the gender in the inferior third of the upper Paraná River. With the submersion of Sete Quedas waterfalls, a segment of the middle section of the Paraná River became the continuity of the upper Paraná River and populations of Steindachnerina brevipinna were introduced in the area. Those close species could be forming natural hybrids and starting a process of genetic homogenization in the area. The main goal of this research was to establish methodology for the molecular characterization of S. insculpta and S. brevipinna and to identify possible hybrids through the SPAR methodology. Diagnostic molecular markers were obtained for the two species and only one among the 50 analyzed individuals presented markers of both parental species, indicating to be a natural hybrid. Due to the low number of hybrid individuals found, we may infer that they are probably sterile and they are not backcrossing with parental species. Therefore, there are no long term risks of introgression of genes in the genetic pool of both species.