Genetic population structure of the deep-sea whelk Buccinum tsubai in the Japan Sea

Abstract

The purpose of the present paper was to examine the genetic population structure of Buccinum tsubai in the Japan Sea. Mitochondrial 16SrRNA gene sequence analysis was performed with specimens from various stations in the Japan Sea. Mitochondrial lineages were clearly patterned geographically in four separate areas: the Hokkaido area, the Yamagata-Toyama area, the Yamato Bank area, and the San'in area. The main distribution depth range of B. tsubai is between 200 m and 1000 m isodepths, and the horizontal distance between the 200 m and 1000 m isodepth lines represents the specific spatial scale of the habitat (SSSH). These four areas were separated either by the complete discontinuity of the SSSH area or by its narrow spatial extension. Genetic distances between the main haplotypes of each area were calculated as Jukes-Cantor distances, the value of which ranged between 0.012 and 0.017. This value seemed to be unrelated to the geographic distance. There was no tendency for clustering according to depth. In future, the morphological characters of the four lineages of B. tsubai should be compared in detail in order to elucidate significant genetic differences among them.