Genetic differentiation among populations of the Japanese turban shell Turbo (Batillus) cornutus corresponding to warm currents

The nucleotide sequences of a highly polymorphic region of the mitochondrial gene for cytochrome oxidase I (237 base pair) were determined for 240 individual specimens of the Japanese turban shell Turbo (Batillus) cornutus collected from 12 sites around Japan. Synonymous nucleotide substitutions were detected at 34 positions, and the 49 haplotypes obtained were divided into 2 clusters that formed 'star' phylogenies. The distribution of the 2 clusters was closely related to the pathways of the 2 warm currents along the Japanese Islands, namely, the Kuroshio and Tsuskima Currents. The appearance of 2 clusters in the Japan Sea and the Seto Inland Sea is probably attributable to gene flow through the Kanmon Strait during the past 5000 yr, The genetic polymorphism found among the natural populations of the Japanese turban shell provides useful information with which to assess the anticipated genetic disturbance introduced by human activities, such as stocking with artificially bred juveniles.