羊毛尾线虫线粒体nad4基因的序列变异分析

Analysis of Sequence Variation in Mitochondrial nad4 Gene of Trichuris ovis Isolates

本研究旨在阐明中国羊毛尾线虫(Trichuris ovis)广东分离株线粒体NADH脱氢酶亚单位4(nad4)基因部分序列(pnad4)的遗传变异情况,并用pnad4序列构建其与其他鞭虫的进化关系。应用PCR扩增羊鞭虫虫株的pnad4,将所获得的序列应用ClustalX 1.81程序进行比对,然后用Mega 5.0程序NJ法绘制种系发育树。本试验扩增所获得的pnad4序列长度一致,均为827bp,种内变异在0～1.5%之间。种系发育分析结果表明,12个羊鞭虫分离株位于同一分支。由于羊鞭虫nad4序列种内相对保守,种间差异较大(37.8%～45.6%),故可作为种间鉴定检测研究的遗传标记,本研究结果为进一步研究羊鞭虫的群体遗传结构奠定了基础。

The objectives of the present study were to analyze sequence variation in the NADH dehydrogenase subunit 4 （nad4） gene among Trichuris ovis isolates from Guangdong province in China, and to study its phylogenetic relationships with other whipworms using the nad4 gene sequences. The partial nad4 （pnad4） were amplified from individual T.ovis samples, and pnad4 sequences were aligned using the ClustalX 1.81. Neighbor-joining （NJ） trees were constructed using the software Mega version 5.0. The lengths of all pnad4 sequences were 827 bp. Phylogenetic analyses showed that all T.ovis isolates were clustered in the same clade.Sequence variations in pnad4 sequences within T.ovis were 0 to 1.5%, which was significantly lower than inter-species differences （37.8% to 45.6%）. It was concluded that pnad4 sequence could be used as a genetic marker for population genetic studies of T.ovis, as well as for the differentiation and identification of different whipworms. The results of this study provided foundation for further studies on molecular genetics and diagnostics of T.ovis.