Abstract:

Objective To investigate the genetic difference of cytochrome oxidaseⅠ（COⅠ）of Oncomelania snails from the project of afforestation for schistosomiasis control in marshland regions，so as to explore the effects of different ecological environ? ments. Methods The snails were collected from 3 different areas，Anqing，Tongling，Wuwei，i.e. the upstream，midstream and downstream regions along the Yangtz River in Anhui Province. Genomic DNA was extracted from the snails，and COⅠ gene frag? ments were amplified by PCR，then purified and sequenced. The sequences were edited by using Blast. The COⅠ genes of O. h. minima and Biomphalaria glabrata were used as the reference of exogenous gene. The genetic distances of the various regions were calculated by the Kimura method and phylogenetic trees were constructed with UPGMA and the NJ method of MEGA（3.1）soft? ware. Results The amplified COⅠ gene of the snail was a fragment about 700 bp including 2 primers in length. There were little genetic diversity among the different areas，the identities were higher than or equal to 98%. The genetic distances indicated that the distance between the projects of afforestation and woodland in Anqing was 0.003，while Tongling was 0.019，Wuwei was 0.007. The distances among the three projects of afforestation were 0.003-0.012. The two phylogenetic trees were constructed by the methods of UPGMA and NJ respectively，which took on very similar topo?structure in which isolates of Biomphalaria glabrata located in one clade and all the others in the other one. In the other one clade，O. H .minima located in one clade. There was little genetic diversity among Anqing，Tongling，Wuwei clusters. The afforestations of Anqing and Wuwei clustered into one group， while the woodlands of Anqing and Wuwei appeared as another group. Conclusion There is a little genetic diversity of the snail cytochrome oxidaseⅠ（COⅠ）in different ecological environments among the upstream，midstream and downstream regions along the Yangtz River in Anhui Province.

Key words: Oncomelania snail, Project of afforestation for schistosomiasis control, Ecology environment, Cytochrome oxidaseⅠ(COⅠ)

摘要：

目的 分析安徽省湖沼型血吸虫病流行区林业血防工程区钉螺细胞色素氧化酶Ⅰ （COⅠ） 基因的差异性， 探讨林业血防工程中不同生态环境对钉螺生态的影响。方法 采集长江安徽段上游安庆、 中游铜陵、 下游无为等3地林业血防工程区和草滩对照点钉螺， 提取DNA， PCR扩增COⅠ基因并测序。采用blast对COⅠ基因比较相似性。采用微小钉螺、 双脐螺COⅠ基因序列作为外群参照序列， Kimura双参数法计算遗传距离， MEGA 3.1软件非加权组平均法 （UPGMA） 和邻近法（NJ） 构建系统发生树。结果 PCR扩增获得的COⅠ基因约为700 bp （含两端引物）。各地林业工程区之间， 各林业工程区与其草滩对照点之间的COⅠ基因相似性均较高， 均≥98%； 安庆、 铜陵、 无为等3地林业工程区之间遗传距离为0.003～ 0.012， 3地林业工程区与草滩对照点的遗传距离分别为0.003、 0.019、 0.007。2种方法构建的进化树拓扑结构基本一致。进化树分2大分支， 双脐螺独立成一大支， 其他的成一大支 （在这大支中微小钉螺又成一支）， 3地的林业工程区与对照草滩钉螺基因差异比较小。 结论 长江安徽段上、 中、 下游林业血防工程区钉螺COⅠ基因在不同的生态环境下可能已存在一定程度的遗传分化， 但分化程度较低。

关键词: 钉螺； 林业血防； 生态环境； 细胞色素C氧化酶Ⅰ