不同地域株湖北钉螺CO1基因的差异研究

目的　研究中国大陆及台湾地区不同地域株湖北钉螺CO1基因的差异,为湖北钉螺种下分类提供依据。方法　收集13个地域株的湖北钉螺,高盐法抽提细胞内全部DNA ,PCR法扩增线粒体CO1基因,纯化并测序。将测序结果输入MEGA2程序,Kimura双参数法计算遗传距离,并分别用UPGMA法和最小进化法构建系统发生树。结果PCR扩增获得CO1基因大小约70 0bp(含两侧引物)。遗传距离显示:13个地域株明显被分为两组,其中四川株和云南株为一组,组内遗传距离为0 .0 35 ,其余为另一组,组内平均遗传距离为0 .0 14。而两组间的遗传距离为0 .12 9。两种方法构建的进化树拓扑结构基本一致。进化树分两大支,四川株和云南株位于一支,其它地域株位于另一支。结论13个自然隔离株湖北钉螺CO1基因总体差异不大,显示为一个种,其中四川、云南株与其它地域株差异显著,支持以往滇川亚种的结论,长江中下游各地域株CO1基因非常相近,支持指名(或湖北)亚种的分类方法。福建株、台湾株的分类地位有待进一步探讨。光壳和肋壳钉螺CO1基因无差异。

Study on CO1 Gene Diversity among Different Isolates of Oncomelania hupensis in China

To study CO1 gene diversity among isolates of Oncomelania hupensis in China.Snails were collected from 13 different areas distributed in 10 provinces in China. Mitochondria cytochrome C oxidase 1 (CO1) gene fragments of the snails were amplified by PCR method and then purified and sequenced. Program Mega 2.1 was used for sequence analysis. Genetic distances were computed and phylogenetic trees were constructed with UPGMA and ME method respectively.Showed that the CO1 genes amplified were about 700bp ( including 2 primers). Genetic distances indicated that the 13 isolates clustered into 2 groups: group 1 included isolates of Sichuan and Yunnan with the in-group distnce of 0.035, group 2 was composed of all the others with the average in-group distance of 0.014. While the distance between the two groups was 0.129. The two phylogenetic trees respectively constructed by method of UPGMA and ME took on very similar topo-structure in which isolates of Sichuan and Yunnan located in one clade and all the others amalgamated in the other one. The overall difference of the CO1 gene among the 13 isolates is not very apparent. It indicates all of them belong to one species. The hypothesis that isolates of Sichuan and Yunnan constitute subspecies of O.hupensis robertsoni and isolates from middle and lower drainage areas of Yangzi River all belong to subspecies of O.hupensis hupensis is further proved. But the classification of isolates of Fujian and Taiwan needs further study. There is no difference in the CO1 gene between rough-rib and smooth-rib snails.