弓首蛔虫线粒体cox1基因的多态性研究

Study on DNA polymorphism in mitochondrial cytochrome c oxidase subunit 1 within and among Toxocara species

应用PCR SSCP技术和DNA 序列分析对犬弓首蛔虫(Toxocara canis)线粒体DNA(mtDNA)中的细胞色素c氧化酶第I亚基(cox1)基因部分序列(pcox1)进行了分析研究,并与弓首属的猫弓首蛔虫、马来西亚弓首蛔虫、牛弓首蛔虫及弓蛔属的狮弓蛔虫进行了种间比较。结果显示,犬弓首蛔虫种群内的pcox1 序列差异为2.72%,与马来西亚弓首蛔虫种群间的序列差异为11.38%,与猫弓首蛔虫种群间的序列差异为11. 20%,与牛弓首蛔虫种群间的序列差异为10.40%,与狮弓蛔虫种群间的序列差异为11.48%;马来西亚弓首蛔虫种群内的pcox1 序列差异为0.57%,与猫弓首蛔虫的序列差异为8.23%,与牛弓首蛔虫的序列差异为8.70%,与狮弓蛔虫的序列差异为10.60%。研究证实,犬弓首蛔虫不同地方虫株的pcox1 有一定差异,与同属其他种类及狮弓蛔虫的差异较大;马来西亚弓首蛔虫确为一独立种。

Sequence heterogeneity in a portion of the mitochondrial cytochrome c oxidase subunit 1 gene (pcox1) was examined in Toxocara canis from different geographical locations using SSCP analysis followed by DNA sequencing and compared with that of Toxocara cati, Toxocara malaysiensis, Toxocara vitulorum and Toxascaris leonina. While the average intraspecific variation in the pcox1 sequence was (2.72%) for T.canis from different geographical origins, interspecific differences were 11.38% between T.canis and T.malaysiensis, 11.20% between T.canis and T.cati, 10.40% between T.canis and T. vitulorum, and 11.48% between T.canis and T.leonina. These findings have important implication for studying molecular ecology and population genetic structures of Toxocara species.