Morgan Jess A T, Dejong Randall J, Adeoye Grace O, Ansa Ebenezer D O, Barbosa Constança S, Brémond Philippe, Cesari Italo M, Charbonnel Nathalie, Corrêa Lygia R, Coulibaly Godefroy, D'Andrea Paulo Sérgio, De Souza Cecilia Pereira, Doenhoff Michael J, File Sharon, Idris Mohamed A, Incani R Nino, Jarne Philippe, Karanja Diana M S, Kazibwe Francis, Kpikpi John, Lwambo Nicholas J S, Mabaye Amadou, Magalhães Luiz A, Makundi Asanteli, Moné Hélène, Mouahid Gabriel, Muchemi Gerald M, Mungai Ben N, Séne Mariama, Southgate Vaughan, Tchuenté Louis Albert Tchuem, Théron Andre, Yousif Fouad, Zanotti-Magalhães Eliana M, Mkoji Gerald M, Loker Eric S
Department of Biology, University of New Mexico, Albuquerque, New Mexico 87131 USA.
Mol Ecol. 2005 Oct;14(12):3889-902. doi: 10.1111/j.1365-294X.2005.02709.x.
Schistosoma mansoni is the most widespread of the human-infecting schistosomes, present in 54 countries, predominantly in Africa, but also in Madagascar, the Arabian Peninsula, and the Neotropics. Adult-stage parasites that infect humans are also occasionally recovered from baboons, rodents, and other mammals. Larval stages of the parasite are dependent upon certain species of freshwater snails in the genus Biomphalaria, which largely determine the parasite's geographical range. How S. mansoni genetic diversity is distributed geographically and among isolates using different hosts has never been examined with DNA sequence data. Here we describe the global phylogeography of S. mansoni using more than 2500 bp of mitochondrial DNA (mtDNA) from 143 parasites collected in 53 geographically widespread localities. Considerable within-species mtDNA diversity was found, with 85 unique haplotypes grouping into five distinct lineages. Geographical separation, and not host use, appears to be the most important factor in the diversification of the parasite. East African specimens showed a remarkable amount of variation, comprising three clades and basal members of a fourth, strongly suggesting an East African origin for the parasite 0.30-0.43 million years ago, a time frame that follows the arrival of its snail host. Less but still substantial variation was found in the rest of Africa. A recent colonization of the New World is supported by finding only seven closely related New World haplotypes which have West African affinities. All Brazilian isolates have nearly identical mtDNA haplotypes, suggesting a founder effect from the establishment and spread of the parasite in this large country.
曼氏血吸虫是感染人类的血吸虫中分布最广的一种，存在于54个国家，主要在非洲，但也在马达加斯加、阿拉伯半岛和新热带地区。感染人类的成年寄生虫偶尔也能在狒狒、啮齿动物和其他哺乳动物体内发现。该寄生虫的幼虫阶段依赖于双脐螺属的某些淡水蜗牛物种，这些蜗牛在很大程度上决定了寄生虫的地理分布范围。从未使用DNA序列数据研究过曼氏血吸虫的遗传多样性在地理上以及在使用不同宿主的分离株之间是如何分布的。在这里，我们使用从53个地理分布广泛的地点收集的143个寄生虫的2500多个碱基对的线粒体DNA（mtDNA）来描述曼氏血吸虫的全球系统地理学。发现物种内mtDNA存在相当大的多样性，85个独特的单倍型分为五个不同的谱系。地理隔离而非宿主使用似乎是该寄生虫多样化的最重要因素。东非的样本显示出显著的变异，包括三个分支和第四个分支的基部成员，强烈表明该寄生虫在30万至43万年前起源于东非，这一时间框架与它的蜗牛宿主的到来时间相符。在非洲其他地区发现的变异较少但仍然很大。仅发现七个与西非有亲缘关系的密切相关的新大陆单倍型，这支持了新大陆是近期才被殖民的观点。所有巴西分离株都具有几乎相同的mtDNA单倍型，这表明该寄生虫在这个大国的建立和传播产生了奠基者效应。
