PCR Primers for Microsatellite Loci in Tuna Species of the Genus Thunnus and its Application for Population Genetic Study

Abstract

Microsatellite loci were isolated from a size-selected genomic library of Pacific northern tuna Thunnus thynnus orientalis, and PCR primer sets to amplify four loci were designed. Investigation on genetic polymorphism at these loci in the Pacific northern bluefin tuna sample (n=35-40) revealed high degree of length polymorphisms in all loci, in which number of alleles per locus ranged from 8 to 23 and observed heterozygosity from 0.533 to 1. These primer sets were applied to Atlantic northern bluefin tuna T. t. thynnus, albacore T. alalunga, bigeye tuna T. obesus and yellowfin tuna T. albacares, detecting polymorphism in all loci comparable with those of Pacific northern bluefin tuna. Significant differences in the allele frequency were observed between Pacific and Atlantic northern bluefin tuna samples. These primer sets developed for Pacific northern bluefin tuna appeared to be useful for amplifying homologous microsatellite loci in the other Thunnus tuna species, and may have great potential as indicators for genetic variability within and between samples of tuna species of the genus Thunnus.