Data from: Phylogeny of seven Bulinus species originating from endemic areas in three African countries, in relation to the human blood fluke Schistosoma haematobium

Background: Snails species belonging to the genus Bulinus (Planorbidae) serve as intermediate host for flukes belonging to the genus Schistosoma (Digenea, Platyhelminthes). Despite its importance in the transmission of these parasites, the evolutionary history of this genus is still obscure. In the present study, we used the partial mitochondrial cytochrome oxidase subunit I (cox1) gene, and the nuclear ribosomal ITS, 18S and 28S genes to investigate the haplotype diversity and phylogeny of seven Bulinus species originating from three endemic countries in Africa (Cameroon, Senegal and Egypt). Results: The cox1 region showed much more variation than the ribosomal markers within Bulinus sequences. High levels of genetic diversity were detected at all loci in the seven studied species, with clear segregation between individuals and appearance of different haplotypes, even within same species from the same locality. Sequences clustered into two lineages; (A) groups Bulinus truncatus, B. tropicus, B. globosus and B. umbilicatus; while (B) groups B. forskalii, B. senegalensis and B. camerunensis. Interesting patterns emerge regarding schistosome susceptibility: Bulinus species with lower genetic diversity are predicted to have higher infection prevalence than those with greater diversity in host susceptibility. Conclusion: The results reported in this study are very important since a detailed understanding of the population genetic structure of Bulinus is essential to understand the epidemiology of many schistosome parasites.背景：隶属于双脐螺属（Bulinus，扁卷螺科Planorbidae）的螺类，是隶属于血吸虫属（Schistosoma，复殖纲Digenea，扁形动物门Platyhelminthes）的吸虫的中间宿主。尽管该类群在这类寄生虫的传播过程中发挥着关键作用，但其演化历程至今仍不甚明晰。本研究选取线粒体细胞色素C氧化酶亚基I（cox1）基因片段，以及核核糖体ITS、18S和28S基因作为分子标记，对源自非洲3个血吸虫病流行国（喀麦隆、塞内加尔、埃及）的7种双脐螺属物种的单倍型多样性与系统发育关系展开了探究。结果：在双脐螺属的序列中，cox1基因区域的变异程度远高于核糖体类分子标记。在7个研究物种的所有检测位点中均检测到高水平的遗传多样性，即便在同一采样地点的同一物种内，个体间也呈现出清晰的遗传分化，并存在多种不同的单倍型。所有序列可聚类为两个支系：支系A包含截形双脐螺（Bulinus truncatus）、热带双脐螺（B. tropicus）、球形双脐螺（B. globosus）以及脐形双脐螺（B. umbilicatus）；支系B则包含福氏双脐螺（B. forskalii）、塞内加尔双脐螺（B. senegalensis）与喀麦隆双脐螺（B. camerunensis）。针对血吸虫易感性的分析呈现出有趣的规律：遗传多样性较低的双脐螺属物种，其血吸虫感染率预计高于遗传多样性更高的类群。结论：本研究所得结果具有重要意义，因为要深入解析多种血吸虫寄生虫的流行病学特征，明晰双脐螺属的种群遗传结构是必不可少的前提。