长蛸(Octopus variabilis)不同地理群体遗传多样性的ISSR分析

GENETIC DIVERSITY OF DIFFERENT GEOGRAPHICAL POPULATIONS IN OCTOPUS VARIABILIS REVEALED BY ISSR ANALYSIS

利用ISSR分子标记技术获得长蛸的ISSR-PCR最优反应体系,并对大连、烟台、青岛、连云港、舟山、温州、厦门7个群体168个个体进行遗传多样性分析。结果表明,7个引物在7个群体中共扩增出118条重复性好且带型清晰的ISSR扩增带,其中多态条带为55条,多态性比例达46.61%。在物种水平上的Nei’s基因多样性指数和Shannon’s信息指数分别为0.3145和0.4766,在群体水平上分别为0.1573和0.2355。7个群体可明显聚类为2个类群,AMOVA分子变异分析发现,长蛸54.64541%的变异发生在群体间,45.35459%的变异发生在群体内。群体间的遗传分化系数Gst为0.5067和由Gst估算的基因流Nm为0.4867<1。分析显示长蛸具有较高遗传多样性水平,但群体间已经出现了较大程度的遗传分化。

In this study, genetic diversity among 168 individuals of 7 different geographical populations of the Octopus variabilis were analyzed after we had established the ISSR-PCR optimal reaction system by the Inter-Simple Sequence Repeat （ISSR） markers. The samples of the seven populations were taken from Dalian, Yantai, Qingdao, Lianyungang, Zhoushan, Wenzhou and Xiamen, respectively. Under predetermined optimal reaction conditions, total of 118 reproducible and clear DNA fragnaents from seven populations were amplified with seven primers, in which 55 fragments were polymorphic, and the proportion of polymorphic loci was 46.61%. The Nei＇s gene diversity and Shannon＇s information index of the O. variabilis was 0.3145 and 0.4766 at species level, 0.1573 and 0.2355 at population level, respectively. 7 populations could be apparently divided into 2 groups. The AMOVA demonstrated that the among-population component accounted for 54.64541% of the total variation, while the within-population component accounted for 45.35459%. The genetic differentiation coefficient （Gst） and the gene flow （Nm） were 0.5067 and 0.4867 （〈 1）, respectively among the 7 populations. These data indicate that the genetic diversity of O. variabilis is relatively high, and there is genetic differentiation of some extent among the seven populations of O. variabilis.