Recent genetic exchanges and admixture shape the genome and population structure of the zoonotic pathogen Cryptosporidium parvum
Recent genetic exchanges and admixture shape the genome and population structure of the zoonotic pathogen Cryptosporidium parvum
复制标题
最近的遗传交换和混合塑造了人畜共患病病原体微小隐孢子虫的基因组和种群结构
DOI：
10.1111/mec.16556
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发表时间：
2022-06-16
影响因子：
4.9
通讯作者：
Caccio, Simone M.
中科院分区：
文献类型：
--
作者：
Corsi, Giulia, I;Tichkule, Swapnil;Caccio, Simone M.
微小隐孢子虫是一种全球性分布的人畜共患病原体，是引起人类和反刍动物腹泻的主要原因。寄生虫的生命周期包括一个强制性的有性阶段，在此期间，以前孤立的谱系之间可以发生遗传交换。在这里，我们比较了从欧洲、埃及和中国收集的32个人源性和反刍动物源性寄生虫分离株的全基因组序列。我们确定了三个强有力的支持集群，包括来自不同宿主物种，地理来源和亚型的分离株的混合。我们证明：（1）在反刍动物分离株与人类分离株之间发生重组;（2）这些重组区域可以通过基因流动和种群混合传递给其他人类亚型;（3）存在多种遗传交换，并且大多数可能是最近的;（4）推定的毒力基因在这些遗传交换中显著富集，以及（5）这导致其核苷酸多样性增加。我们仔细剖析了两个基因交换的系统发育序列，说明了这些事件的长期进化后果。我们的研究结果表明，全球化的增加和密切的人畜接触增加了以前孤立的寄生虫谱系之间的遗传交流的机会，导致溢出和回溢事件。我们讨论了如何这可以提供一个新的基板，自然选择的基因参与宿主-寄生虫的相互作用，从而可能改变的动态协同进化平衡的红皇后军备竞赛。
Cryptosporidium parvum is a globally distributed zoonotic pathogen and a major cause of diarrhoeal disease in humans and ruminants. The parasite's life cycle comprises an obligatory sexual phase, during which genetic exchanges can occur between previously isolated lineages. Here, we compare 32 whole genome sequences from human- and ruminant-derived parasite isolates collected across Europe, Egypt and China. We identify three strongly supported clusters that comprise a mix of isolates from different host species, geographic origins, and subtypes. We show that: (1) recombination occurs between ruminant isolates into human isolates; (2) these recombinant regions can be passed on to other human subtypes through gene flow and population admixture; (3) there have been multiple genetic exchanges, and most are probably recent; (4) putative virulence genes are significantly enriched within these genetic exchanges, and (5) this results in an increase in their nucleotide diversity. We carefully dissect the phylogenetic sequence of two genetic exchanges, illustrating the long-term evolutionary consequences of these events. Our results suggest that increased globalization and close human-animal contacts increase the opportunity for genetic exchanges between previously isolated parasite lineages, resulting in spillover and spillback events. We discuss how this can provide a novel substrate for natural selection at genes involved in host-parasite interactions, thereby potentially altering the dynamic coevolutionary equilibrium in the Red Queens arms race.