鸡蛔虫线粒体cox1基因的克隆及序列分析

Cloning and Sequence Analysis of Mitochondrial cox1 Gene of Ascaridia galli Isolates from Different Provinces in China

本研究旨在阐明鸡蛔虫分离株线粒体细胞色素c氧化酶第Ⅰ亚基(cox1)基因部分序列(pcox1)的遗传变异情况,并用pcox1序列构建其与其他蛔虫的进化关系。应用聚合酶链反应(PCR)扩增鸡蛔虫虫株的pcox1,将测定获得序列应用Clustal X 1.81程序进行比对,然后用Phylip 3.67程序MP法和Mega 4.0程序NJ法绘制种系发育树,并用Puzzle 5.2程序构建最大似然树。所获得的pcox1序列长度一致,均为250bp,种内变异在0～2.5%之间。种系发育分析表明,8个鸡蛔虫分离株位于同一分枝。由于鸡蛔虫pcox1序列种内相对保守,种间差异较大(6.9%～15.3%),故可作为种间遗传变异研究的标记,研究结果为进一步研究鸡蛔虫的群体遗传结构奠定了基础。

The objectives of the present study were to analyze sequence variations in the cytochrome c oxidase subunit 1 （coxl） gene among Ascaridia galli isolates from different provinces in China,and to study its phylogenetic relationships with roundworms of the other families using coxl gene sequence. The partial coxl （pcoxl） were amplified from each A. galli sam- ple,and pcoxl sequences were aligned using the Clustal X 1.81. MP and NJ trees were constructed using the software Phylip 3.67 version 4.0 and Mega version 4.0, and ML tree was also constructed using Puzzle version 5.2. The lengths of all the pcoxl sequences were 250 bp. Phylogenetic analyses showed that the eight isolates were clustered in the same clade. Sequence variations in pcoxl sequences within A. galll were 0 to 2. 5% which was significantly lower than inter-species differences （6.9% to 15.3%）. It is concluded that pcoxl sequences can be used as genetic marker for population genetic studies of A. gal- li. The results of this study provided foundation for further studies on molecular genetics and diagnostics of A. galli.