细颈囊尾蚴四川和云南分离株线粒体nadl和coxl基因的序列测定与种系发育分析

SEQUENCE AND PHYLOGENETIC ANALYSIS OF MITOCHONDRIAL NAD1 GENE AND COX1 GENE FOR CYSTICERCUS TENUICOLLIS IN SICHUAN AND YUNNAN PROVINCE

用PCR方法扩增分离自我国四川和云南2省5地山羊和猪共24个细颈囊尾蚴标本的线粒体烟酰胺腺嘌呤二核苷酸还原酶第1亚基（nadl）基因部分序列（pnadl）和细胞色素c氧化酶第1亚基（coxl）基因全序列，分析其遗传变异，并用MEGA4．0程序NJ法和Bayesian3．1程序贝叶斯推理法绘制种系发育树，探讨不同地区来源的细颈囊尾蚴种群间的遗传相似性及其他带科带属绦虫的亲缘关系。测序结果显示，细颈囊尾蚴的pnadl序列长度为780bp，coxl基因全序列长度为1620bp。pnadl和coxl基因序列均存在一定的遗传变异，且pnadl序列的变异高于coxl基因序列。系统发育树显示，所有细颈囊尾蚴构成一个分支，可分为3个亚群，均未形成明显的地理分支或宿主分支。因此nadl基因是更适合于研究细颈囊尾蚴系统发生的遗传标记，同时两者在种内均相对保守，与其他带科绦虫种间差异较大，故均可用于细颈囊尾蚴的分子分类。

The partial sequences of mitochondrial NADH dehydrogenase subunit 1 （pnadl） gene and the complete sequences of the cytochrome c oxidase subunit I （ coxl ） gene of 24 C. tenuicollis samples isolated from five different cities in Sichuan province and Yunnan province were amplified by PCR, and sequenced to analyse their genetic variations, NJ tree and Bayesian tree was constructed using the MEGA version 4. 0 software and Bayesian version 3.1, respectively. The results showed that the partial sequence of nadl gene and complete sequence of coxl gene of C. tenuicollis were 780 bp and 1 620 bp, respectively. There were some genetic variations in pnadl gene and coxl gene within C. tenuicollis, the level of variation was higher in the pnadl gene than in the coxl gene. The phylogenetic trees showed that all the C. tenuicollis isolates were formed a single cluster that could be divided into three subgroups, there was no obvious geography cluster or host cluster. So nadl gene was more suitable to study phylogenetic relationship of C. tenuicolliz. Meanwhile, there was no significant variation in the nadl and coxl gene sequences within C. tenuicollis, while inter-species differences were obvious, so they also can be used to molecular classification of C. tenuicoUis. The results of the present study provided foundation for further studies of population genetics of T. hydatigena.