COVID-19 is seriously threatening human health all over the world. A comprehensive understanding of the genetic mechanisms driving the rapid evolution of its pathogen (SARS-CoV-2) is the key to controlling this pandemic. In this study, by comparing the entire genome sequences of SARS-CoV-2 isolates from Asia, Europe and America, and analyzing their phylogenetic histories, we found a lineage derived from a recombination event that likely occurred before March 2020. More importantly, the recombinant offspring has become the dominant strain responsible for more than one-third of the global cases in the pandemic. These results indicated that the recombination might have played a key role in the pandemic of the virus.

COVID-19 正在严重威胁全世界的人类健康。全面了解驱动其病原体 (SARS-CoV-2) 快速进化的遗传机制是控制这一流行病的关键。在这项研究中，通过比较来自亚洲、欧洲和美洲的 SARS-CoV-2 分离株的全基因组序列，并分析它们的系统发育历史，我们发现了一个可能发生在 2020 年 3 月之前的重组事件的谱系。更重要的是，重组后代已成为导致全球三分之一以上大流行病例的主要毒株。这些结果表明重组可能在病毒大流行中发挥了关键作用。