曲腿龟甲轮虫和热带龟甲轮虫的mtDNA COI基因和rDNA ITS序列差异以及几种龟甲轮虫的系统发生关系

摘要

Individuals of Keratella valga and K.tropica were respectively collected from Lake Jinghu and Lake Tingtang in Wuhu city,and clonally cultured in the laboratory.COI gene and rDNA ITS sequences of 30 K.valga and K.tropica clones were amplified,sequenced and analyzed.With B.calyciflorus as an outgroup,COI gene and ITS sequences of 60 K.tropica and K.valga clones,and those of several Keratella species downloaded from Genbank,were used to construct the molecular phylogenetic trees (Maximum-Likelihold,Maximum-Parsimony,Neighbor-Joining and Bayesian trees).The results showed that the sequence divergence of COI genewas24.9％-26.5％ between K.valga and K.tropica,but that was0-2％ and 0-1.5％ within K.valga and K.tropica,respectively.The sequence divergence of ITS was 6.1％-7.6 ％ between K.tropica and K.valga,but that was 0-1.1％ and 0-0.7％ within K.tropica and K.valga,respectively.Four phylogenetic trees supported that the haplotypes of K.tropica and K.valga were divided into two different clades,respectively.%从芜湖市镜湖和汀棠湖中分别采得曲腿龟甲轮虫(Keratella valga)和热带龟甲轮虫(K.tropica)个体,实验室内对其进行克隆培养.运用常规的分子生物学技术,对各30个曲腿龟甲轮虫克隆和热带龟甲轮虫克隆分别进行了mtDNA COI基因和rDNA ITS的扩增、测序和序列分析.以萼花臂尾轮虫轮虫(Brachionus calyci florus)为外群,结合Genbank上已登录的几条其它龟甲轮虫COⅠ基因和ITS序列,以及测序所得的60个COI基因和ITS序列构建系统发生树(ML、MP、NJ和贝叶斯树).结果表明,曲腿龟甲轮虫和热带龟甲轮虫间COI基因序列差异百分比为24.9％-26.5％,平均为25.7％.曲腿龟甲轮虫个体间序列差异百分比为0-2％,热带龟甲轮虫个体间序列差异百分比为0-1.5％.两种轮虫间ITS序列差异百分比为6.1％-7.6％,平均为7.25％.曲腿龟甲轮虫个体间序列差异百分比为0-1.1％,热带龟甲轮虫个体间序列差异百分比为0-0.7％.基于COI基因序列和ITS序列构建的四个系统树均支持曲腿龟甲轮虫单倍型和热带龟甲轮虫单倍型各自成支.