UCL Genetics Institute, University College London, London, UK.
The Francis Crick Institute, London, UK.
Nat Ecol Evol. 2024 May;8(5):960-971. doi: 10.1038/s41559-024-02353-4. Epub 2024 Mar 25.
Most emerging and re-emerging infectious diseases stem from viruses that naturally circulate in non-human vertebrates. When these viruses cross over into humans, they can cause disease outbreaks, epidemics and pandemics. While zoonotic host jumps have been extensively studied from an ecological perspective, little attention has gone into characterizing the evolutionary drivers and correlates underlying these events. To address this gap, we harnessed the entirety of publicly available viral genomic data, employing a comprehensive suite of network and phylogenetic analyses to investigate the evolutionary mechanisms underpinning recent viral host jumps. Surprisingly, we find that humans are as much a source as a sink for viral spillover events, insofar as we infer more viral host jumps from humans to other animals than from animals to humans. Moreover, we demonstrate heightened evolution in viral lineages that involve putative host jumps. We further observe that the extent of adaptation associated with a host jump is lower for viruses with broader host ranges. Finally, we show that the genomic targets of natural selection associated with host jumps vary across different viral families, with either structural or auxiliary genes being the prime targets of selection. Collectively, our results illuminate some of the evolutionary drivers underlying viral host jumps that may contribute to mitigating viral threats across species boundaries.
大多数新发和再现传染病都源自于在非人类脊椎动物中自然循环的病毒。当这些病毒跨越物种进入人类时，它们可能引发疾病爆发、流行和大流行。尽管从生态角度对人畜共患病宿主跳跃进行了广泛研究，但很少关注描述这些事件背后的进化驱动因素和相关性。为了弥补这一空白，我们利用了所有公开可用的病毒基因组数据，采用了一套全面的网络和系统发育分析来研究近期病毒宿主跳跃的进化机制。令人惊讶的是，我们发现人类既是病毒溢出事件的来源，也是其归宿，因为我们从人类推断出更多的病毒宿主跳跃，而不是从动物到人类。此外，我们证明了涉及假定宿主跳跃的病毒谱系进化加快。我们进一步观察到，宿主跳跃相关的适应性程度对于宿主范围较广的病毒较低。最后，我们表明，与宿主跳跃相关的自然选择的基因组靶标在不同的病毒家族中有所不同，结构或辅助基因是主要的选择靶标。总的来说，我们的研究结果阐明了一些病毒宿主跳跃的进化驱动因素，这可能有助于减轻跨越物种界限的病毒威胁。
