Estudos genéticos em Kalyptodoras bahiensis, capturada na bacia do médio e baixo Paraguaçu-BA, através de marcadores citogenéticos e moleculares.

Abstract

The Paraguaçu River Basin has been the target of various human actions, the main one was the construction of 17 dams along the River. The peculiarities of the local fauna, characteristic of the reservoir, dam design, operational procedures, uses of the basin, the nature of the soil, resulting flow and interactions between these variables constitute a sample of this complexity. This fact associated with the great influence that the degradation caused and the great exploitation of the species that inhabit them make the genetic studies an important tool to help species identification and monitoring of genetic variations occurring in fish stocks. Kalyptodoras bahiensis is a catfish of Doradidae’s family endemic of the Paraguaçu river and is currently threatened with extinction due to various anthropic activities. This study was conducted from January-October 2010 and aimed to characterize the Kalyptodoras bahienses through classical cytogenetic markers (Giemsa) and molecular-genetic markers (ISSR), knowing the chromosome number and genetic variability of the intra and inter species. Samples were collected from 121 animals for morphological and cytogenetic analysis for 15 animals at five sites distributed along the middle and lower Paraguaçu. Molecular markers used showed major bands monomorphic and polymorphic bands secondary, characterized as follows: GGAC - three patterns; AAGC - four patterns, and TAGG - two patterns. Kalyptodoras bahiensis presents 2n = 58 chromosomes for both males and for female specimens. These results agree with those described in the literature, where the lower number is diploid 2n = 42 and 2n = 62 is higher for the genus Siluriforme. The result is confirmed with the literature data to the family Doradidae where there is the maintenance of the diploid number of 2n = 58 in the studied species. With this study we concluded that Kalyptodoras bahiensis showed no significant variation in the species-specific chromosome pattern, indicating that the cromossomic number was maintained without major changes when compared with other representatives of the family Doradidae. Although preliminary, this study defines the genetic profile for three genetic markers and suggests levels of intrapopulation molecular diversity, which is of great importance in maintaining the viability and survival of the species. This material will serve as an important tool and may define a way for monitoring and conservation of the genetic heritage of Kalyptodoras bahiensis.