Genetic structure of Korean populations of the clam Ruditapes philippinarum inferred from microsatellite marker analysis

The Korean littleneck clam, Ruditapes philippinarum, is a valuable and intensively exploited species in Korea. Attention to genetics can enhance strategies for using fishery resources sustainably, and a potentially important application is the use of molecular markers to assess the genetic stock structure of a harvested species. In this study, seven microsatellite loci were analyzed in five littleneck clam samples from the western and southern coasts of Korea to investigate the genetic characteristics of these clams. Very high genetic diversity was present in all five of the populations (overall He = 0.813), but no significant differences among the localities were detected (Wilcoxon signed-rank test, P > 0.05). The results showed a significant global F-ST (0.045), indicating genetic heterogeneity among the populations. We found three genetically distinct regions: a western coastal region (F-ST range 0.0137-0.0218, P > 0.005) and two regions along the southern coast of Korea (F-ST range 0.0473-0.1121, P < 0.005). Neighbor-joining, principle coordinate analysis, and Bayesian clustering revealed the existence of these three groups. This result was also corroborated by an analysis of molecular variance (AMOVA) and an assignment test. This report presents novel observations of the wild genetic population structure in littleneck clams along the coast of Korea and provides critical information to support conservation strategies for this species. The three groups mentioned above could be considered independent management units, and the southern groups would have a higher conservation priority due to their unique genetic characteristics. (C) 2012 Elsevier Ltd. All rights reserved.