基于线粒体COⅠ基因的团聚牡蛎(Saccostrea malabonensis,Faustino,1932)遗传多样性研究OA北大核心CSCDCSTPCD

Saccostrea malabonensis is a filter-feeding bivalve widely distributed along the western Pacific coasts,where it plays a key role in water purification and ecosystem functioning.In recent years,the known geographical range of this species has extended beyond its initially recorded locations along the Chinese coast.However,its ge-netic diversity,population structure,and evolutionary history remain poorly understood.In this study,we examined the genetic diversity of S.malabonensis across the Pacific region using mitochondrial cytochrome oxidase subunit Ⅰand 16S rRNA genes.Sampling included ten sites in China,three in Japan,one in the Philippines,three in the Bay of Bengal,and five in the Caribbean Sea.The results revealed no significant phylogenetic differentiation among western Pacific populations(China,Japan,and the Philippines),and their genetic diversity was comparable to that of the Caribbean populations.In contrast,the Bay of Bengal populations exhibited substantial genetic divergence from both the western Pacific and Caribbean populations(Fst=0.39217 and 0.38454,respectively;P<0.05)and harbored higher genetic diversity.Haplotype network analyses suggested possible source-sink relationships among regions;however,limited sampling from the Bay of Bengal prevents clear resolution of the precise historical con-nections between this region and the western Pacific.Notably,the Caribbean populations displayed a genetic struc-ture closely resembling that of the western Pacific populations,showing only minor differentiation.This pattern suggests a potential introduction pathway through international shipping or hull fouling,possibly via the Panama Canal.Historical demographic analyses further indicated that several western Pacific populations(including those from China,Japan,and the Philippines)may have undergone demographic expansion during post-glacial warming and sea-level rise following the Last Glacial Maximum.