Efficient detection of parentage in a cultured Japanese flounder Paralichthys olivaceus using microsatellite DNA marker

Parentage of offspring in a stock of a cultured Japanese flounder Paralichthys olivaceus was determined using four hyper-variable microsatellite DNA loci with many unique alleles. It was found that only 57% of the 14 broodstock parents actually contributed to the production of offspring in this experiment. The number of alleles per locus in the offspring was reduced 29% compared to the broodstock. The average heterozygosity of offspring (He=0.883) was significantly lower (P<0.01) than that of their parents (He=0.943). In this study, use of hyper-variable microsatellite markers with many rare alleles was effective for unambiguous parentage determination and estimation of genetic diversity in hatchery and natural populations of Japanese flounder. And it was shown using parentage determination that the difference between the number of parents contributing to reproduction and the number of fish stocked caused loss of genetic variability.