基于ITS序列的捻转血矛线虫系统进化分析

Phylogenetic Analysis of Haemonchus contortus Based on ITS Sequence

为分析捻转血矛线虫ITS序列的变异与虫株特性之间的关系,对捻转血矛线虫不同药物抗性虫株(苯并咪唑类药物抗性虫株、伊维菌素抗性虫株、莫西菌素抗性虫株、药物敏感虫株)、不同宿主来源虫株(长颈鹿、牛、绵羊、山羊、牦牛)和不同地理位置(中国、美国、意大利、法国、也门、马来西亚、澳大利亚)的分离株,以及毛圆科的其他线虫的ITS序列进行了分析。结果发现捻转血矛线虫与毛圆科其他线虫的ITS-2基因的相似性高,基于该基因建立的系统进化树可以很好地区分毛圆科不同属的线虫;捻转血矛线虫的抗药性特点与其ITS-1基因的变异进化关系不大;不同地理位置的捻转血矛线虫分离株的ITS-2基因变异很小;从野生动物长颈鹿体内分离的捻转血矛线虫的ITS-1基因与家养反刍动物分离株的差异较明显。研究结果表明捻转血矛线虫ITS序列在种内相对保守,不同虫株间变异较小,在毛圆科线虫的分子分类中具有一定意义。

To understand whether the characters of Haemonchus contortus were related to the variations of the internal transcribed spacer（ITS） sequences,the strains resistant to benzimidazole,ivermectin and moxidectin;strains isolated from giraffe,cattle,sheep,goat and yak;isolates from China,USA,Italy,France,Yemen,Malaysia and Australia,and other nematodes in the family of trichostrongylidae were collected and their ITS sequences were analyzed.The results showed that the ITS-2 sequences in the worms of family trichostrongylidae were similar.The phylogentic tree based on ITS-2 sequences indicated that different genus in the family could be distinguished by the tree.The variations of H.contortus ITS-1 were not related to the drug resistance or susceptivity.Comparisons of the sequences of ITS-2 of the isolates from different place in the world did not show too many variations.However,the ITS-1 of H.contortus isolated from domestic hosts seems to be different from that of the wild giraffe.These results indicated that ITS sequences of H.contortus were conserved in the parasites and could be used in the molecular taxonomy.