Tandem repeat arrays in the mitochondrial genome as a tool for detecting genetic differences among the ark shell S capharca broughtonii

We found that tandem repeat ( TR ) arrays were present in the ark shell S capharca broughtonii mitochondrial genome, and we demonstrated the efficiency of using this TR region as a tool for the detection of genetic differentiation. In samples collected from seven populations off the J apanese, C hinese, R ussian and K orean coasts, five TR types with length ranging from 481 to 601 bp (base pairs) were found, as were 18 haplotypes (n = 155). All the Japanese samples from SD , IK , AM and KG , which represented four geographically distinct populations, had the same type of tandem repeat array, 481‐ TR . All the samples from C hina and all but one sample from R ussia had the same TR type, 511‐ TR ; these finding may be strong evidence that the ark shell populations in C hina and R ussia are very similar. Based on a neighbor‐joining dendrogram of haplotypes, the K orean population was divided into two groups as follows: samples with haplotype H 481‐3 and samples with haplotypes H 601‐1, H 601‐2, H 601‐3 or H 541‐1. Based on the haplotype diversity and nucleotide diversity, the C hinese, R ussian and K orean populations showed a higher diversity than J apanese populations (P < 0.05).