多鳞四指马鲅和四指马鲅种群遗传特征的研究

Population Genetic Characteristics of Eleutheronema rhadinum and Eleutheronema tetradactylus in China

为了探明中国东海和南海多鳞四指马鲅和四指马鲅的遗传多样性及种群遗传结构特征。采用线粒体COI序列和D-loop序列作为分子标记对福州、泉州和珠海的多鳞四指马鲅及徐闻的四指马鲅进行了分析。研究结果显示徐闻的四指马鲅与NCBI数据库下载的马来西亚群体的亲缘关系近。多鳞四指马鲅COI序列的单倍型多样性和核苷酸多样性分别为0.894和0.002,D-loop序列的单倍型多样性和核苷酸多样性分别为0.994和0.041。四指马鲅COI序列的单倍型多样性和核苷酸多样性分别为0.901和0.002,D-loop序列的单倍型多样性和核苷酸多样性分别为0.998和0.012。AMOVA结果显示多鳞四指马鲅的遗传差异主要来自群体内而不是群体间。两两群体的遗传分化系数显示中国沿海的多鳞四指马鲅群体无显著遗传分化,为单一随机交配种群,但与四指马鲅有显著遗传差异。基于邻接法构建的系统发育树发现四指马鲅和多鳞四指马鲅的可被本研究的2种分子标记(COI序列和D-loop序列)区分。基于COI序列的中性检验和核苷酸错配分布发现,多鳞四指马鲅在更新世经历过种群快速扩张,群体扩张时间可能在(2.4~7.2)万年前。综上,中国东海和南海的多鳞四指马鲅为单一种群,渔业资源管理时需作为一个单元进行管理。

To investgate the genetic diversity and population genetic structure of East Asian fourfinger threadfin Eleutheronema rhadinum and fourfinger threadfin E.tetradactylum from the East China Sea and South China Sea,the mitochondrial COI and D-loop sequences of 85 specimens for E.rhadinum collected from Fuzhou(FZ),Quanzhou(QZ)and Zhuhai(ZH)and 30 specimens for E.tetradactylum collected from Xuwen(XW)were sequenced and analyzed.Neighbour-joining tree showed that the samples of E.tetradactylum from Xuwen were genetic closely related to the Malaysian population(sequences were download from NCBI).Genetic diversity analysis showed that E.rhadinum with relatively high haplotype diversity(COI,0.894;D-loop,0.994)and relatively low nucleotide diversity(COI,0.002;D-loop,0.041),and the similar results were found in E.tetradactylum with relatively high haplotype diversity(COI,0.901;D-loop,0.998)and relatively low nucleotide diversity(COI,0.002;D-loop,0.012).Median-joining network of E.rhadinum showed that the haplotypes were connected in a star-like manner for two mitochondrial markers.Analysis of molecular variance(AMOVA)of E.rhadinum indicated that all the genetic variation was from individuals within population rather than from the populations.The pairwise FST suggest that E.rhadinum is a random mating population with low non-significant genetic differentiation in south China,but significantly differentiated from the species of E.tetradactylum.Neighbor-joining phylogenetic analysis revealed that E.rhadinum and E.tetradactylum are two different species from the same genus and can be identified by the two mitochondrial DNA markers.The demographic history examined by neutrality tests and mismatch distribution analysis based on COI sequence suggest that a sudden population expansion might date to 24000 to 72000 years BP at the Pleistocene Epoch.In conclusion,E.rhadinum from the coastal waters of China belong to the same population and should be managed as a unit in fishery management.