A review of genetic intra- and interspecific relationships of deep-sea Buccinum and Neptunea species around Japan (with special reference to the Sea of Japan)

抄録

The Sea of Japan is a marginal sea surrounded by narrow, shallow straits which became isolated from neighboring waters when the sea level fell during the Pleistocene glacial periods. In order to understand the influences of such paleoenvironmental changes on the formation of populations of marine organisms in the Sea of Japan, deep-sea whelks (genera Buccinum and Neptunea (Buccinidae)) are appropriate materials considering their low dispersal abilities through direct development. Deep-sea whelks are also important marine species for fisheries in the Sea of Japan. However, several taxonomical problems due to morphological variations and lack of knowledge about gene flows among local populations in deep-sea whelks may lead to inappropriate fisheries management. We and my collaborators examined the genetic inter- and intraspecific relationships of deep-sea Buccinum and Neptunea species by means of molecular markers with samples from various stations around Japan (mainly from the Sea of Japan). We found some intriguing genetic structures closely related to their characteristic reproductive mode and paleoenvironmental changes in the Sea of Japan. In addition, by comparing inter- and intraspecies relationships of some Buccinum species, I clarified some novel taxonomical aspects of these species. Here, I review these genetic structures of deep-sea whelks and describe the future direction of phylogeographical approaches to deep-sea organisms in the Sea of Japan.