Toxoplasma gondii is among the most successful parasites. It is capable of infecting all warm-blooded animals and causing opportunistic disease in humans. T. gondii has a striking clonal population structure consisting of three predominant lineages in North America and Europe. Clonality is associated with the recent emergence of a monomorphic version of Chr1a, which drove a selective genetic sweep within the past 10,000 years. Strains from South America diverged from those in North America some 1-2 mya; recently, however, the monomorphic Chr1a has extended into regions of South America, where it is also associated with clonality. The recent spread of a few dominant lineages has dramatically shaped the population structure of T. gondii and has resulted in most lineages sharing a highly pathogenic nature. Understanding the factors that have shaped the population structure of T. gondii has implications for the emergence and transmission of human pathogens.

中文翻译：

---

弓形虫的种群结构：由不频繁的重组和选择性扫描驱动的克隆扩张。

弓形虫是最成功的寄生虫之一。它能够感染所有温血动物并引起人类机会性疾病。刚地弓形虫具有惊人的克隆种群结构，由北美和欧洲的三个主要谱系组成。克隆性与最近出现的单态版本的 Chr1a 相关，它在过去的 10,000 年内推动了选择性遗传扫描。南美洲的菌株与北美的菌株相差 1-2 米；然而，最近，单态性 Chr1a 已扩展到南美洲地区，在那里它也与克隆性有关。最近几个主要谱系的传播极大地塑造了刚地弓形虫的种群结构，并导致大多数谱系具有高致病性。