Laboratory of Malariology, Research Institute for Microbial Diseases, Osaka University, Osaka 565-0871, Japan.
Curr Biol. 2010 Jul 27;20(14):1283-9. doi: 10.1016/j.cub.2010.05.053. Epub 2010 Jun 17.
Plasmodium falciparum is distributed throughout the tropics and is responsible for an estimated 230 million cases of malaria every year, with a further 1.4 billion people at risk of infection. Little is known about the genetic makeup of P. falciparum populations, despite variation in genetic diversity being a key factor in morbidity, mortality, and the success of malaria control initiatives. Here we analyze a worldwide sample of 519 P. falciparum isolates sequenced for two housekeeping genes (63 single nucleotide polymorphisms from around 5000 nucleotides per isolate). We observe a strong negative correlation between within-population genetic diversity and geographic distance from sub-Saharan Africa (R(2) = 0.95) over Africa, Asia, and Oceania. In contrast, regional variation in transmission intensity seems to have had a negligible impact on the distribution of genetic diversity. The striking geographic patterns of isolation by distance observed in P. falciparum mirror the ones previously documented in humans and point to a joint sub-Saharan African origin between the parasite and its host. Age estimates for the expansion of P. falciparum further support that anatomically modern humans were infected prior to their exit out of Africa and carried the parasite along during their colonization of the world.
疟原虫恶性疟原虫分布于热带地区，每年估计有 2.3 亿疟疾病例，另有 14 亿人面临感染风险。尽管遗传多样性的变化是发病率、死亡率和疟疾控制工作成功的关键因素，但人们对恶性疟原虫种群的基因构成知之甚少。在这里，我们分析了来自世界各地的 519 株恶性疟原虫分离株的样本，这些样本针对两个管家基因（每个分离株约 5000 个核苷酸的 63 个单核苷酸多态性）进行了测序。我们观察到，在非洲、亚洲和大洋洲，种群内遗传多样性与撒哈拉以南非洲的地理距离之间存在强烈的负相关关系（R(2) = 0.95）。相比之下，传播强度的区域差异似乎对遗传多样性的分布没有影响。恶性疟原虫中观察到的这种明显的地理隔离模式与以前在人类中记录的模式相呼应，并表明寄生虫与其宿主之间存在共同的撒哈拉以南非洲起源。对恶性疟原虫扩张的年龄估计进一步支持了这样一种观点，即在现代人离开非洲之前就已经被感染，并在其殖民世界的过程中携带了寄生虫。
