COVID-19 severity and the Neanderthal heirloom

Why do some people experience severe COVID-19 symptoms while others appear to have mild or no symptoms at all? According to recently published research in Nature, the answer may have to do with an ancient heirloom: Neanderthal DNA.

In June of this year, data from the Helix research community helped an international team of researchers identify a patch of DNA that appears to influence whether a person gets severe COVID-19. Reported in the New England Journal of Medicine, the team described how people who experienced severe COVID-19 tended to have variations in their DNA sequence in multiple locations within this small stretch of DNA. This correlation is not causation, but it does suggest that this section of DNA may be an important factor in determining how severe a person’s COVID-19 symptoms are.

After reading this paper, one of the world’s foremost experts on archaic DNA took an interest. Svante Pääbo, a Swedish geneticist, has been a leading figure in the study of Neanderthal DNA and how fragments of Neanderthal DNA have been passed down through generations to modern humans.

Pääbo’s team of researchers were interested to see if the section of DNA that was associated with COVID-19 severity could have come from Neanderthals. (This question was born from the fact that this patch of DNA appeared relatively unchanged in large swaths of people—a characteristic sign of Neanderthal DNA.)

By analyzing DNA taken from Neanderthal fossils and comparing it with modern genomes, the researchers concluded that this patch of DNA was very likely inherited from Neanderthal relatives. They also found that this patch of DNA was more commonly found in people with European or South Asian ancestors—a pattern that reflects the geographic regions where researchers believe Neanderthals lived throughout much of history.

This research is just the beginning and will need many follow up analyses to better understand the significance of these findings, but it does propose some interesting possibilities.

For example, the fact that this section of DNA has persisted in our DNA over tens of thousands of years suggests that it may have been beneficial to us in some way, providing enough benefit to outweigh the severe effects that might result from infection with coronaviruses. Alternatively, the relative absence of this patch of DNA in people with East Asian ancestry could be evidence that this section of DNA may have negatively affected populations in East Asia during ancient times.

For now, these possibilities are just speculation—there just isn’t much evidence to tell us why this section of DNA has been passed to modern humans; it is entirely possible that this bit of Neanderthal DNA has survived through generations based on pure chance.

To read more about how Helix’s research community is helping to advance COVID-19 research, click here.