Utilização de AFLP para estudos genéticos em Prochilodus argenteus (Pisces, Prochilodontidae)

Abstract

Genetic studies have been performed for an endemic species from São Francisco River basin, Prochilodus argenteus, which has a great importance in the artisanal and subsistence fishing in the region. The linkage mapping and the genetic variability studies were made with AFLP (Amplified Fragment Length Polymorphism) dominants markers and with 189 specimens from a F1 cross, that was also used for restocking the upstream area from Três Marias hydroelectric dam. All the analyses were carried out with 15 primer pairs combinations and the linkage map was made using the pseudo-testcross mapping strategy. Forty six heterozygous marks were found for the genitors, with mendelian segregation of 1:1. The female genitor map had 3 linkage groups and the lenght of the analysed genome was 128,45 cM, the male genitor map had the same number of linkage groups and the total length of 192,67 cM. Common markers for both genitors, with mendelian segregation ratio of 3:1, served as bridge between the maps, for the construction of an integrated map. This map had 9 linkage groups, and the total map length was 442,08 cM. Additionally, the genetic variability was assessed and an expected heterozygosity mean was of 0,32082, with a Jaccard s similarity coefficient of 0,72564 + 0,00451. These preliminary values show that the cultured sample has a higher similarity coefficient than that obtained for the wild populations. Hence, the present results suggest that genetic studies and management restocking practices should be simultaneously performed for the maintenance of the genetic patrimony of this species at the São Francisco River basin. The results also showed that AFLP marks were suitable and effective to identify linkage marks in Prochilodus argenteus and for genetic variability studies in cultivar samples.