Population genetic structure of the pen shell Atrina pectinata sensu lato (Bivalvia: Pinnidae) throughout East Asia

Abstract

The pen shell (Atrina pectinata sensu lato) is a commercially important but endangered mollusk in East Asia, requiring special attention for resource management. Whereas the presence of several cryptic species is considered to occur along the coast of China, the genetic structure around Japan is not well understood. We collected 664 individuals from twelve sites in Japan and from one site in South Korea, sequenced their mitochondrial cytochrome c oxidase subunit I (mtCOI) gene, and conducted phylogeographic analyses together with 540 mtCOI sequences previously reported for China and the Korean Peninsula. As a result, A. pectinata s. l. was found to be comprised of six monophyletic lineages (lineages 1–6) which were identical to those of previous studies. Lineages 1 and 2 have a broad range of geographical distribution from the eastern coast of the Asian continent to Japan. Hierarchical AMOVA revealed a significant genetic differentiation among groups of sampling sites both in lineages 1 and 2, inferring the effects of post-recruitment selection or coastal topography. Some of the sampling sites around Japan had two or three lineages, and careful attention is needed for the resource management in these sites because lineage identification by external morphology is impossible in some cases.