Ancient recombination events between human herpes simplex viruses

Herpes simplex viruses 1 and 2 (HSV-1 and HSV-2) are seen as close relatives but also unambiguously considered as evolutionary independent units. Here, we sequenced the genomes of 18 HSV-2 isolates characterized by divergent UL30 gene sequences to further elucidate the evolutionary history of this virus. Surprisingly, genome-wide recombination analyses showed that all HSV-2 genomes sequenced to date contain HSV-1 fragments. Using phylogenomic analyses, we could also show that two main HSV-2 lineages exist. One lineage is mostly restricted to subSaharan Africa whereas the other has reached a global distribution. Interestingly, only the worldwide lineage is characterized by ancient recombination events with HSV-1. Our findings highlight the complexity of HSV-2 evolution, a virus of putative zoonotic origin which later recombined with its human-adapted relative. They also suggest that coinfections with HSV-1 and 2 may have genomic and potentially functional consequences and should therefor...单纯疱疹病毒1型和2型（Herpes simplex viruses 1 and 2，HSV-1与HSV-2）虽被视为近缘类群，但同时也被明确认定为进化上相互独立的演化单元。本研究对18株携带差异化UL30基因序列的HSV-2分离株进行了全基因组测序，以期进一步阐明该病毒的演化历程。令人意外的是，全基因组重组分析结果显示，截至目前所有已测序的HSV-2基因组均携带有HSV-1的基因片段。通过系统基因组学分析，本研究还证实HSV-2存在两个主要演化支系：其中一个支系主要局限于撒哈拉以南非洲区域，另一个支系则已实现全球分布。值得注意的是，仅该全球分布支系呈现出与HSV-1发生古老重组事件的特征。本研究结果凸显了HSV-2演化的复杂性：该病毒被推测起源于动物宿主，后续又与其适应人类的近缘病毒发生了重组事件。此外，本研究结果还提示，HSV-1与HSV-2的合并感染可能会产生基因组层面乃至潜在功能层面的影响，因此应予以重视（原文表述未完结）