Mitochondrial DNA diversity in wild and cultured populations of Brycon opalinus (Cuvier, 1819) (Characiformes, Characidae, Bryconinae) from the Paraı́ba do Sul Basin, Brazil

Abstract RFLP analysis of mitochondrial DNA was carried out to investigate the population genetic structure of cultured and wild populations of Pirapitinga-do-sul— Brycon opalinus (Cuvier, 1819) (Characiformes, Characidae, Bryconinae) from the Paraiba do sul basin, Brazil. mtDNA samples were collected from 257 specimens sampled in seven rivers of the Paraiba basin and in a hatchery used for restocking. An initial screening with 24 restriction enzymes revealed six informative enzymes, which generated 27 haplotypes. Haplotype diversities were high both in the hatchery broodstock ( h =0.75) and in the samples from the wild ( h =0.60). Nucleotide diversity among the 27 B. opalinus haplotypes was 0.825%. Analysis of molecular variance (AMOVA) showed the highest variance within populations (70.48%) while 28.16% of the total diversity was due to interpopulation variance, suggesting the existence of genetic differentiation among B. opalinus populations.