Scientists don’t yet know if a particular piece of human DNA passed down from Neanderthal interbreeding 60,000 years ago increases the risk of severe illness from covid-19. The coronavirus, like all viruses, has made the ‘dark energy’ of evolution visible, occupying an odd “liminal space” in the life of our planet, not quite alive, but not dead –a hidden world, almost a “first Earth.” New findings, reports Carl Zimmer, author of A Planet of Viruses, for the New York Times, show how some clues to modern health stem from ancient history.
A Biological “M&M”
Like all viruses, we know that Covid-19 is basically nano-encapsulated genetic information, writes the Santa Fe Institute’s David Krakauer and Dan Rockmore for Nautil.us –“They have existed from the beginning of biological time, emergent from the proverbial primordial soup, a string of atoms, clumped into molecules, wrapped in another kind of molecular shell, a kind of biological M&M.”
The “Neanderthal” piece of the genome, which spans six genes on Chromosome 3, is now common in Bangladesh, observes Zimmer, “where 63 percent of people carry at least one copy. Across all of South Asia, almost one-third of people have inherited the segment.” The dark segment is far less common in Europe,where only eight percent carry it, with only 4 percent in East Asia and virtually absent in Africa.
Evolutionary Pattern a Mystery
It’s not clear what evolutionary pattern produced this distribution over the past 60,000 years, said Hugo Zeberg, a geneticist at the Karolinska Institute in Sweden who was one of the authors of the new study. “One possibility,” reports Zimmer, “is that the Neanderthal version is harmful and has been getting rarer over all. It’s also possible that the segment improved people’s health in South Asia, perhaps providing a strong immune response to viruses in the region.”
“One should stress that at this point this is pure speculation,” said study co-author, Svante Paabo, the director of the Max Planck Institute for Evolutionary Anthropology.