It's not yet understood why this particular stretch of DNA causes the higher risk of severe illness, but the study was published online on bioRxiv and has yet to be peer-reviewed or published in a scientific journal.
History having repercussions today
As per Joshua Akey, a geneticist at Princeton University who was not involved in the new study and who spoke to the New York Times, "This interbreeding effect that happened 60,000 years ago is still having an impact today."
The six-pieced genome, which is part of the Chromosome 3, is most common in people from Bangladesh, where 63% of the population carries at least one copy. Around one-third of people across South Asia carry the segment, whereas in other parts of the world it's far less common.
The scientists working on the study have yet to figure out why the genome is distributed in such a way across the world.
As the researchers said themselves "One should stress that at this point this is pure speculation," said the geneticist at the Karolinska Institute in Sweden Hugo Zeberg’s co-author, Svante Pääbo, the director of the Max Planck Institute for Evolutionary Anthropology in Leipzig, Germany.
In regards to the effects of COVID-19 on people around the world, researchers are slowly understanding more and more how people are affected differently. For instance, why older people are generally more prone to catching it severely, and that men are more at risk than women.
So those who carry two copies of this DNA variant are three times more likley to suffer severe conditions of the coronavirus.
People who typically suffer from severe cases of COVID-19 do so because their immune systems go on overdrive and uncontrollably attack, which ends up scarring their lungs and causing dramatic inflammation.