中国近海重要生态建群红藻真江蓠的群体遗传多样性

真江蓠(Gracilaria vermiculophylla)是中国近海潮间带生态系统结构组成和功能维持的重要支撑物种, 但有关其群体遗传结构和多样性分布模式的研究目前仍较缺乏。本研究利用线粒体cox1序列对我国近海19个真江蓠地理群体进行了系统发育和群体遗传分析。461个长度为641 bp的cox1序列片段共含有21个多态位点, 产生15个单倍型。基于cox1序列的系统进化分析、单倍型分析和主成分分析显示, 19个真江蓠群体分化为南北两个类群, 其中浙江嵊泗以北的13个群体形成北方类群, 福建厦门以南的6个群体形成南方类群。遗传距离和分子方差分析显示真江蓠南北各类群内的遗传分化较小, 南北类群间的遗传分化达到亚种水平。南北类群间的差异是我国近海真江蓠群体遗传变异的主要来源。

Genetic diversity of the habitat-forming red alga Gracilaria vermiculophylla along Chinese coasts

As a habitat-forming species, the red alga Gracilaria vermiculophylla has been noted to play an essential role in shaping coastal marine communities and maintaining intertidal ecosystems along Chinese coasts. However, few studies have been conducted that analyze the genetic structure of the population and the distribution patterns of genetic variation. In this study, we compiled partial mitochondrial DNA cytochrome c oxidase subunit I gene (cox1) of 19 G. vermiculophylla populations (461 individuals) and performed phylogenetic analysis and population genetic surveys. A total of 461 mt-DNA cox1 sequences were obtained and edited into 641 bp, which contained 21 polymorphic sites and yielded 15 haplotypes. Phylogenetic inferences, haplotype networking, and principal coordinate analysis consistently indicated that G. vermiculophylla populations diverged into two groups: the northern group is comprised of specimens from the Yellow-Bohai Sea and the Shengsi Islands, while the southern group is comprised of specimens from six locations south to Xiamen, Fujian Province. Analysis of the molecular variance and Nei’s genetic distances indicated low genetic differentiation between populations in each group while group-level genetic divergence is comparable to the degree of subspecies differentiation.