Population genetic structure of sea cucumber, Stichopus japonicus in Korea using microsatellite markers

摘要

Sea cucumber (Stichopus japonicus) is a commercially valuable species in Korea. We examined the genetic characteristics of sea cucumber populations in Korea using microsatellite markers. A total of 144 sea cucumbers from five populations were typed for nine polymorphic microsatellite loci. A total of 139 different alleles were found over all loci and many alleles were unique. The average number of allele per locus ranged from 6 to 18.4. The average observed and expected heterozygosities ranged from 0.532 to 0.626 and from 0.719 to 0.789 respectively. All populations showed significant departure from Hardy-Weinberg equilibrium at almost all loci except one (Psj2409). This deviation was in the direction of heterozygote deficit. A phylogenetic tree revealed two distinct clusters. One cluster was formed by the eastern sea population. A second cluster consisted of the subpopulations of the western and southern sea populations. The eastern sea population showed genetic differences such as a larger number of alleles per locus, a larger number of unique alleles and a smaller number of the most common alleles, suggesting a higher genetic diversity in this population. These results provide basic information on natural population genetic structure of S. japonicus in Korea.