An ancient coronavirus, or a closely related pathogen, triggered an epidemic among ancestors of present-day East Asians roughly 25,000 years ago, a new study indicates.
Analysis of DNA from more than 2,000 people shows that genetic changes in response to that persistent epidemic accumulated over the next 20,000 years or so, David Enard, an evolutionary geneticist at the University of Arizona in Tucson, reported April 8 at the virtual annual meeting of the American Association of Physical Anthropologists. The finding raises the possibility that some East Asians today have inherited biological adaptations to coronaviruses or closely related viruses.
Notably, modern human genomes contain evolutionary information tracing back tens of thousands of years, which may help identify the viruses that have impacted our ancestors – pointing to which viruses have future pandemic potential. Here, we apply evolutionary analyses to human genomic datasets to recover selection events involving tens of human genes that interact with coronaviruses, including SARS-CoV-2, that likely started more than 20,000 years ago. These adaptive events were limited to the population ancestral to East Asian populations. Multiple lines of functional evidence support an ancient viral selective pressure, and East Asia is the geographical origin of several modern coronavirus epidemics. An arms race with an ancient coronavirus, or with a different virus that happened to use similar interactions as coronaviruses with human hosts, may thus have taken place in ancestral East Asian populations. By learning more about our ancient viral foes, our study highlights the promise of evolutionary information to better predict the pandemics of the future. Importantly, adaptation to ancient viral epidemics in specific human populations does not necessarily imply any difference in genetic susceptibility between different human populations, and the current evidence points toward an overwhelming impact of socioeconomic factors in the case of COVID-19