黄海蓝点马鲛mtDNA D-loop序列变异分析

采用聚合酶链式反应(PCR)技术对山东半岛南岸水域的蓝点马鲛(Scomberomorus niphonius)群体(n＝20)的mtDNA D—1oop序列进行扩增，获得了大小约为500bp的扩增产物。PCR产物经纯化后进行序列测定，得到了410bp的核苷酸片段(除去引物及部分端部序列)。用Genedoc软件进行排序比较，在这20个个体中，共检测到54个变异位点，包括2个碱基缺失、1个碱基插入、43个转换位点、7个颠换位点及2个转换与颠换同时存在的位点。运用MEGA软件计算出不同个体间的遗传距离，并据此构建了UPGMA和NJ系统树。用DNASP软件计算出的多态位点数(S)为54、核苷酸多样性(Pi)和平均核苷酸差异数(K)分别为0．0271和11．047。研究结果表明，蓝点马鲛的mtDNA D—1oop基因个体变异程度较大，适合于群体内及群体间不同个体的遗传多样性分析。

Genetic diversity of Scomberomorus niphonius in the Yellow Sea revealed by mtDNA D-loop sequence

The PCR technique was used to amplify the mtDNA D-Loop in 20 individuals of Spanish mackerel (Scomberomorus niphonius) collected from the Yellow Sea, along the southern coast waters of Shandong Peninsula. The PCR products were purified and sequenced. As a result, 410 bp nucleotide sequences of partial D-Loop gene were obtained (the primer and some of the marginal sequences were excluded). By using Genedoc to align and compare the sequences of these 20 individuals with each other, 54 variation sites were observed, of which there were two deletions, one insertion, 43 transition sites, seven transversion sites and two transition-transversion sites. The pairwise genetic distances were computed by MEGA. The UPGMA and NJ phylogenetic trees were obtained through the cluster analysis over the pairwise genetic distance. As estimated by DNASP, the number of polymorphic sites (S) is 54; the nucleotide diversity (Pi) and the average number of nucleotide differences (K) are 0. 027 1 and 11.047 , respectively. It can be concluded that the variation in mtDNA D-Loop of Spanish mackerel in the Yellow Sea is relatively rich. As a result, mtDNA D-loop can be one of the genetic markers available for scanning genetic diversity of intra-population and inter-populations.