三疣梭子蟹（Portunus trituberculatus）4个野生群体ITS1序列分析及系统进化分析

摘要

The ribosomal DNA internal transcribed spacer 1 （ITS 1） of four wild populations of Portunus trituberculatus was cloned and sequenced. 515--571bp ITS1 fragments were obtained. 56 polymorphic sites were detected. The propor- tion of polymorphic sites was 9.5%, in which parisimony informative sites were up to 25, 40 haplotypes were identified from 60 samples. Haplotype diversity, nucleotide diversity, average number of nucleotide differences and average number of nucleotide substitutions per site were calculated to analyze and compared. The results showed that the colonies from the Zhoushan had highest levels of genetic diversity, followed by Yalu River estuary and Haizhou Bay, Laizhou Bay is the lowest. 5 kinds of microsatellites were found in P trituberculatus. AMOVA analysis results show that the four groups showed significant genetic differences. The molecular phylogenetic tree constructed with NJ method using software MEGA 4.0 to study several species of the Decapoda molecular phylogeny. According to the NJ tree, different species of the same genera were grouped together, in consistence with the morphological taxonomy.%对我国沿海4个野生群体三疣梭子蟹的核糖体RNA转录单元内间隔区ITS1基因片段进行克隆和测序，获得长度为515—571bp的ITS1核苷酸序列，在4个群体的三疣梭子蟹中共检测到变异位点56个，多态位点比例为9．5％，其中简约信息位点25个，共检测到40种单倍型。通过统计单倍型多态性、平均核苷酸差异数和核苷酸多样性指数，结果显示：舟山群体多样性指数最高，其次是鸭绿江口群体和海洲湾群体，莱州湾群体最低。在三疣梭子蟹ITSl序列中共发现5种微卫星位点，AMOVA分析结果显示4个群体间的遗传差异显著。另外，将本研究所得序列结合GenBank数据库中十足目12种蟹ITSl序列构建系统进化树，系统树显示同属的不同种各自聚支，与形态学分类吻合。