Genetic diversity and structure of domesticated strains of red sea bream,Pagrus major,inferred from microsatellite DNA markers

The genetic diversity and structure of nine domesticated strains of red sea bream used in a private hatchery were studied and compared to a wild population. A total of 313 individuals were genotyped at eight microsatellite loci. Average number of alleles per locus ranged from 5.5 to 9.4 in domesticated strains, but that of the wild population was 28.4. Heterozygosity of domesticated strains (ranged 0.697–0.804) was also lower compared to the wild population (0.952). Estimated Ne also decreased in all domesticated strains (ranged 10.3–126.0) compared to the wild population (1422.5). The UPGMA tree and 3‐D FCA showed that there were two main clusters containing domesticated strains, and the wild population was at the middle of both of the domesticated clusters. The STRUCTURE analysis also supported the phylogenetic analysis, and revealed three sub‐clusters in the domesticated strains. Pairwise F_ST revealed that all domesticated strains were statistically different from the wild population, and also the differentiation between domesticated strains was all statistically significant. Information on genetic diversity and structure of domesticated strains of red sea bream obtained in this study will be useful for future broodstock management and selective breeding programmes.