多头带绦虫甘肃分离株分子COⅠ基因部分序列比较分析

Comparison and Analysis of CO I Gene Partial Sequences of Taenia multiceps Isolates from Gansu

应用线粒体DNA中的细胞色素c氧化酶亚基I（COI）基因作为分子标记,对我国甘肃省景泰和平凉地区10个绵羊源脑多头蚴进行分析,与已知带属绦虫种的相应序列进行相似性比较,下载GenBank数据库的带属绦虫COI基因片段序列构建系统进化树,分析其分类及亲缘关系.结果表明,所有多头带绦虫分离株均成功扩增出444 bp的COI基因片段,去除引物序列后多头带绦虫分离株的COI基因片段为396 bp,可以分为4类,共有5个核苷酸变异位点,变异率为0.25%～1.26%.基于COI核苷酸序列的系统进化树表明所有T.multiceps分离株构成一个分支,可分为2个亚群.T.multiceps与T.krabbei 的亲缘关系最近,其次为T.serialis,T.asiatica,T.saginata,与T.ovis等其他带属绦虫关系较远,与T.mustelae关系最远.COI基因序列在种内相对保守,又存在一定的种间差异,可作为带属绦虫分类鉴定研究的分子标记.

The mitochondrial cytochrome c oxidase subunit I （COI） gene was used as a molecular marker to identify Taenia multiceps isolates from 10 sheep in Jingtai and Pingliang area of Gansu Province, China. The CO1 gene fragment was cloned and sequenced from Coerunus cerebralis samples, respectively. Sequence analysis, similarity comparison with the known Taenia species and phylogenetic analysis were performed to study the classification and phylogenetic relationship. The results showed that 444 bp of the COl gene fragment were successfully amplified from all of the 10 T. multiceps isolates. Sequence analysis indicated that the COl gene fragment of 396 bp after the removal of primer sequences can be divided into four types with a total of five nucleotide variant sites （ variant rate from 0. 25% to 1.26% ）. The phylogenetic tree based on COl sequence showed that all T. multiceps isolates constituted a branch that could be divided into two subgroups. T. multiceps and T. krabbei showed the closest relationship, followed by T. serialis, T. asiatica, T. saginata, T. ovis and other Taenia species, with T. mustelae as the most distant species. COI gene sequence was relatively conserved within Taenia species and showed some interspecies differences and can be used as the molecular marker for the interspecific genetic variation study.