Genetic structure of populations of the green turtle (Chelonia mydas) in Japan using mtDNA control region sequences

The green turtle Chelonia mydas is distributed throughout tropical and subtropical oceans worldwide. The Japanese population, the northernmost population of this species, is decreasing due to loss of spawning beaches, and peopling to the coastal area. To examine the genetic structure and genetic diversity of the Japanese population, a total of 294 individuals from seven foraging localities and 20 individuals from two nesting sites were analyzed using muscle and skin samples. The control region of mitochondrial DNA (mtDNA) was amplified with specific primers, and 32 haplotypes were detected from the Japanese population. Haplotype diversities (h) of the southern islands (0.89 at Yaeyama and 0.83 at Amami-Ohshima) were higher than those of the main islands (0.69, 0.63, and 0.67 at Nomaike, Muroto, and Owase, respectively). A median-joining tree using the 32 haplotypes showed three clades, and dominant haplotypes were situated in the middle of each clade. The exact test and F_ST for geographic heterogeneity in haplotype frequency distributions for the five foraging localities showed that significant differences were detected between Yaeyama and the main island localities, and between the Amami-Ohshima and Nomaike/Owase localities