Genetic variation and population structure of hair crab (Erimacrus isenbeckii) in Japan inferred from mitochondrial DNA sequence analysis

Genetic variation and population structure of hair crab (Erimacrus isenbeckii) were examined using nucleotide sequence analysis of 580 base pairs (bp) in the 3' portion of the mitochondrial cytochrome c oxidase subunit I gene (COI) of 20 samples collected from 16 locales in Japan (the Hokkaido and Honshu Islands) and one in Korea. A total of 27 haplotypes was defined by 23 variable nucleotide sites in the examined COI region. Pairwise population F (ST) estimates and neighbor-joining tree inferred distinct genetic differentiation between the representative samples from the Pacific Ocean off the Eastern Hokkaido Island and the Sea of Japan, while others were intermediate between these two groups. AMOVA also showed a weak but significant differentiation among these three groups. The present results suggest a moderate population structure of hair crab, probably influenced by high gene flow between regional populations due to sea current dependent larval dispersal of this species.