基于COⅠ基因序列对我国泰勒虫分类的研究

Toxonomic study of Theileria spp. based on COⅠ gene in China

为理清泰勒虫中国分离株的分类地位,本研究首次对我国报道的5种泰勒虫9个地方分离株的COⅠ基因序列进行测定;并与GenBank中其它泰勒虫COⅠ和相应18S rRNA基因序列分别构建系统发生树,比较基于不同基因的分类结果。结果显示:9株泰勒虫的COⅠ基因大小在1214 bp^1 459 bp,与18S rRNA基因比较,COⅠ基因序列含有较多的变异位点及简约信息位点;基于两个基因的系统发育树,其拓扑结构大体一致。但也存在如下差异:环形泰勒虫不同分离株的聚类分析在COⅠ树中更趋于合理;有关东方泰勒虫和瑟氏泰勒虫命名的争论,本研究给出新的解释。因此,COⅠ基因可以作为新的标记基因用于泰勒虫的分类研究。

In order to clarify the taxonomic status of Theileria spp., the CO I gene were sequenced from 9 isolates of 5 species reported in China. The phylogenetic tree were constructed using CO I and 18S rRNA sequences and also compared result from two phylogenetic tree in this study. As result shown, the length of CO I gene was 1,214 bp to 1,459 bp, and the CO I gene had more variation and informative sites than 18S rRNA. The phylogenetic tree based on CO I and 18S rRNA shared highly similar topological structure. However, there were also some differences between two phylogenetic trees. Such as, the taxonomic status of different isolate of Theileria annulata using CO I gene was more reasonable. Facing the nomenclative controversy of Theileria sergenti and Theileria orientalis, the result gave a new explanation. In conclusion, CO I as a new gene marker could be used in taxonomic study of Theileria spp.