日本の砂浜に生息するチョウセンハマグリ集団の遺伝的多様性と集団構造 ; Genetic diversity and population structure of Meretrix lamarckii from a Japanese sandy beach

Genetic diversity at 14 allozyme loci was examined for 12 local samples of\nMeretrix lamarckii from mainland Japan, an adjacent island (Tanegashima), and one\nsample of Meretrix sp1. collected from Iriomote Island. An unweighted pair group method\nwith arithmetic mean (UPGMA) dendrogram of Nei’s D showed three geographical\nclusters; the Pacific Ocean, the Sea of Japan and Tanegashima. Two warm currents,\nthe Kuroshio and Tsushima, play an important role in the differentiation of the genetic\nstructure between the Pacific Ocean and the Sea of Japan. M. lamarckii inhabit the surf\nzone on exposed sandy beaches, and frequent gene flow between localities was predicted.\nHowever, the pairwise Fst results revealed genetically significant differences among\nJapanese M. lamarckii populations; the Tanegashima, Wakimoto (Kagoshima Pref.),\nMasuda (Shimane Pref.) and Chiribama (Ishikawa Pref.) populations were genetically\nindependent. This is due to the relatively shorter planktonic larval period (5-10 days) of\nM. lamarckii compared to other bivalves (2-4 weeks). No significant genetic differences\nwere observed among the Okuragahama (Miyazaki Pref.), Katakai (Kujyukurihama),\nOoarai (Kashimanada), Akasaki and Nagasuga (Miyagi Pref.) populations. These results\nsuggest that gene flow among the four northern Honshu populations was enabled by the\nwarm Tsugaru current flowing north to south. In contrast, genetic similarities between\nthe Okuragahama (Miyazaki Pref.) and the four northern Honshu populations was due to\naccumulated seedling releases (from Kashimanada to Okuragahama), and not gene flow\ncaused by ocean currents. ; 論文 ; http://purl.org/coar/resource_type/c_6501