Institute of Biodiversity, Animal Health & Comparative Medicine, University of Glasgow, Glasgow, G12 8QQ, UK.
Unit of Molecular Parasitology, Institute of Tropical Medicine Antwerp, 155 Nationalestraat, 2000, Antwerp, Belgium.
Nat Commun. 2019 Sep 3;10(1):3972. doi: 10.1038/s41467-019-11771-z.
Genetic exchange enables parasites to rapidly transform disease phenotypes and exploit new host populations. Trypanosoma cruzi, the parasitic agent of Chagas disease and a public health concern throughout Latin America, has for decades been presumed to exchange genetic material rarely and without classic meiotic sex. We present compelling evidence from 45 genomes sequenced from southern Ecuador that T. cruzi in fact maintains truly sexual, panmictic groups that can occur alongside others that remain highly clonal after past hybridization events. These groups with divergent reproductive strategies appear genetically isolated despite possible co-occurrence in vectors and hosts. We propose biological explanations for the fine-scale disconnectivity we observe and discuss the epidemiological consequences of flexible reproductive modes. Our study reinvigorates the hunt for the site of genetic exchange in the T. cruzi life cycle, provides tools to define the genetic determinants of parasite virulence, and reforms longstanding theory on clonality in trypanosomatid parasites.
遗传交换使寄生虫能够迅速改变疾病表型并利用新的宿主群体。克氏锥虫是恰加斯病的寄生虫病原体，也是拉丁美洲各地的公共卫生关注点，几十年来，人们一直认为它很少进行遗传物质交换，并且没有经典的减数分裂性。我们从厄瓜多尔南部测序的 45 个基因组中提供了令人信服的证据，表明克氏锥虫实际上维持着真正的有性、混合群体，这些群体可以与其他在过去的杂交事件后仍然高度克隆的群体共存。尽管在媒介和宿主中可能共存，但这些具有不同繁殖策略的群体在遗传上似乎是隔离的。我们提出了对我们观察到的细粒度不连续性的生物学解释，并讨论了灵活繁殖模式的流行病学后果。我们的研究重新激发了在克氏锥虫生命周期中寻找遗传交换地点的探索，提供了定义寄生虫毒力遗传决定因素的工具，并重新审视了锥虫属寄生虫克隆性的长期理论。
