Abstract

Fragment of 376 bp at the mitochondrial ND2 gene was sequenced for 133 individuals of Japanese mitten crab, Eriocheir japonica from 17 localities of Japan and 30 individuals of Chinese mitten crab, E. sinensis from 2 localities of China. In Japanese mitten crab, sequence comparison of this segment revealed 23 polymporphic sites, defining 8 haplotypes. However, 30 individuals of Chinese mitten crab from Dandong and Shanghai shared one haplotype. Haplotype diversity and nucleotide diversity, for the17 populations of Japanese mitten crab ranged from 0 to 0.5833 and from 0 to 0.0025, respectively. AMOVA and pairwise F_ST revealed significant genetic differentiation between the Okinawa Island and main islands of Japan, and lack of genetic structure among main islands of the Japan populations. Compared with the genetic distance among populations of two species, the degree of genetic divergence between these two groups (Okinawa and main islands of Japan) is equivalent to the genetic distance between congeneric species. Our results failed to demonstrate significant geographical structure in main islands of Japan, indicating that populations of Japanese mitten crab are capable of extensive gene flow among estuaries along the coastal waters.

Key words: Japanese mitten crab, Eriocheir japonica, Eriocheir sinensis,mitochondiral ND2, genetic structure.