Análise da diversidade genética por meio de marcadores moleculares entre espécies de Cambeva em afluentes do rio Iguaçu

Abstract

Fish are the largest and most diverse group among vertebrates, and the Neotropical region has the greatest diversity of freshwater fishes in the world. However, understanding and studies of the diversity of fish fauna in South America are negatively affected by the lack of research. In this context, the Iguaçu River has a high rate of endemic species in its ichthyofauna, approximately 70% of which are found nowhere else in the world. In this sense, the present work aimed to evaluate the molecular diversity of Cambeva species in tributaries of the Iguaçu River using the ITS1 region. A total of 113 individuals were collected in two cities: Dois Vizinhos and Cascavel. After that, DNA was extracted from a fragment of fish muscle. Then, the ITS1 region was amplified by PCR. Sixty-eight viable sequences were obtained for analysis. The sequences were manually edited and aligned using the BioEdit program, compared using the MEGA X program where the maximum likelihood matrix, the distance between individuals and the phylogenetic tree were obtained. The Popart program was used to build the haplotype network and to identify identical sequences. Thus, it was possible to observe through the data obtained that the genetic variations in Cambeva specimens were associated with their place of origin, with no intraspecific variations between them, corroborating the hypothesis that the geomorphology of the Iguaçu River imposes a geographical barrier to gene exchange, contributing to the process of speciation of the genus and increasing endemism. It was also found that ITS1 is not an efficient marker to separate the species, making it necessary to use other markers, especially mitochondrial markers.