Genetic diversity of wild and cultured populations of Brycon opalinus (Cuvier, 1819) (Characiforme, Characidae, Bryconiae) using microsatellites

Abstract The genetic structure of Brycon opalinus (Brazilian freshwater fish species) from seven wild populations across Paraiba do Sul basin and one cultured population was investigated using 7 microsatellite loci. Polymorphism at all loci was assessed with a total of 162 different alleles found. The observed heterozygosity ( H o ) ranged from 0.23 to 1.00. Almost all populations, except from Itagacaba River, deviated significantly to HWE showing deficit of heterozygote. All populations were characterized by high microsatellite variability (mean H =85.6%). Genetic structure was evidence by a significant F ST (0.0432). All pairwise distances ( F ST ) were significant, suggesting that each population is a different unit of management. The hatchery, stocked since the 50s, showed the second great average allele number: 13.43 and a gene diversity ( H ; observed with microsatellite markers) equal to 0.789. This was similar to previously published mitochondrial data ( h =0.753).