四川省山羊多头蚴线粒体cox2基因序列测定及种系发育分析

SEQUENCING AND PHYLOGENETIC ANALYSIS OF MITOCHONDRIAL COX2 GENE OF COENURUS IN GOATS IN SICHUAN PROVINCE

应用线粒体细胞色素氧化酶第Ⅱ亚基（cox2）基因作为分子标记，对四川省12个山羊源多头蚴样品的cox2基因部分序列（pcox2）进行PCR扩增，分析其种内变异并重建系统进化树。序列分析结果显示所获得的pcox2序列长度为531 bp，共检测到8个变异位点，变异率为0~1.3%。基于pcox2序列构建的系统进化树显示多头蚴四川分离株与已知多头带绦虫位于同一分支，且脑源和肌间多头蚴聚在一起，均为多头带绦虫。结果表明，多头蚴cox2基因种内存在一定的遗传差异，但种内相对保守，与带属其他绦虫种间差异较大，故可作为多头带绦虫种间遗传变异研究的分子标记。这一研究结果也为山羊多头蚴病的分子诊断奠定了基础。

The mitochondrial cytochrome coxidase subunit 2 （cox2） gene was used as a molecular marker to identify the intraspecies variation and reconstruct their phylogenetic relationship of 12 Coenurus isolates collected from goats in Sichuan province. Sequence analysis indicated that the cox2 gene fragment was 531 bp containing a total of 8 nucleotide variant sites. The Phylogenetic tree based on the cox2 sequence showed that all Taeina multiceps isolates clustered together while cerebral and intramuscular specimens grouped together, indicating that all isolates were T. multiceps. There was no significant variation in the cox2 gene sequences within Coenurus although interspecies differences were obvious in Taenia. Therefore, cox2 gene was suitable as a molecular marker to study the intraspecific variation of T.multiceps. The results of the present study paid a solid foundation for molecular diagnosis of coenurosis.