中国沿海长蛸群体16S rRNA基因的遗传变异研究

Genetic Variation in Different Populations of Octopus variabilis in China Coastal Waters based on the 16S rRNA Gene Analysis

采用线粒体16S rRNA基因序列测定技术,分析了我国沿海长蛸4个野生群体的遗传结构及其变异。经比对获得了1个长度为512 bp的核苷酸片段,检测到48个变异位点,占分析位点总数的9.4%,45个个体共检测到30个单倍型,单倍型多样性指数H为0.964 6,总体核苷酸多样性指数Pi为0.032 9,表现出较丰富的遗传多样性。AMOVA分析表明,4个长蛸群体间存在较高的遗传分化,82.07%的遗传差异存在于群体间,而仅有17.93%的遗传差异存在于群体内。聚类分析也表明4个群体可明显聚为2个类群,一个由大连、青岛和舟山群体组成,另一个由厦门群体组成;厦门群体与其它群体间的遗传距离达到0.094,遗传分化系数和基因流分别达到0.97和0.02,表明厦门群体与其它3个群体有着显著的遗传隔离,可能为亚种水平的分化。上述群体间的分化可能与长蛸自身的底栖生活方式、海区水文条件及地理历史因素等有关。

To analyze the genetic variation of Octopus variabilis in China coastal waters,45 individuals were sampled from four localities,including Dalian（DL）,Qingdao（QD）,Zhoushan（ZS） and Xiamen（XM）.Mito-chondrial DNA variation was analyzed using 512 bp segments of 16S rRNA gene,among which 48 polymorphic sites were detected.30 haplotypes were detected out of 45 individuals.The haplotype diversity（H） and nu-cleotide diversity（Pi） were 0.964 6 and 0.032 9,respectively,showing higher genetic diversity in populations.Analysis of molecular variance（AMOVA） suggested that 82.07% of the variation was among populations and showed significant genetic fixation among the four populations.According to the UPGMA phylogenetic tree,four Octopus variabilis populations can be divided into two lineages,one consisting of Dalian,Qingdao and Zhoushan populations and the other consisting of Xiamen population.The genetic distances among the popula-tion of XM and others were up to 0.094, the genetic fixation index and gene flow up to 0.97 and 0.02, respec- tively, showing considerable genetic isolation among XM and other populations, may belong to different sub- species. The above genetic differentiation of Octopus variabilis may be influenced by the factors such as benth- ic lifestyle of Octopus variabilis, hydrological condition of sea areas and geohistory.