Paris (AFP)

Covid-19 patients carrying a segment of Neanderthal DNA, inherited from a cross with the human genome some 60,000 years ago, are at greater risk of severe complications from the disease, according to researchers.

The genetic coding inherited from this distant cousin of the human species makes them, for example, three times more likely to need mechanical ventilation, according to the study published in Nature on Wednesday.

There are many reasons why some patients need intensive care, while others have only mild symptoms, if any.

Being elderly, male, a medical history can worsen the outcome of the disease.

But genetic factors also have a role, according to the study.

“It is striking that the genetic inheritance of Neanderthals has such tragic consequences during the current pandemic,” said one of the co-authors, Svante Paabo, director of the genetics department at the German Max Planck Institute for Anthropological Evolution.

Recent research conducted by the organization "Covid-19 Host Genetics Initiative" reveals that a genetic variant in a certain region of chromosome 3 - one of the 23 in the human genome - is associated with more severe disease.

This same region was already known to harbor genetic code from Neanderthals, which prompted Svante Paabo and his colleague and co-author of the study, Hugo Zeberg, to seek a link to Covid-19.

- Crossings of populations -

They found that a Neanderthal from southern Europe carried a nearly identical genetic segment, made up of some 50,000 base pairs, the primary constituents of DNA.

Telling clue, two Neanderthal specimens found in southern Siberia, and that of another species, Denisova's man, did not carry the famous segment.

The researchers concluded that while modern humans and Neanderthals may have inherited this gene fragment from a common ancestor around half a million years ago, it was more likely to have been integrated into the human genome by more recent population crosses.

This potentially dangerous segment for Covid-19 patients is not distributed evenly across the globe, according to the study.

About 16% of Europeans wear it, and roughly half of the population in South Asia, with the highest proportion (63%) in Bangladesh.

Which could explain why native Bangladeshis living in Britain are two more likely to die from Covid-19 than the general population, assume the study authors.

The incriminated gene segment is almost absent from the genome of the inhabitants of East Asia and Africa.

About 2% of the DNA of non-Africans originates in the genome of Neanderthals, according to several studies.

Denisova's man also transmitted part of his DNA to modern humans, but more modestly on a global scale.

We find less than 1% among Asians and American Indians, and about 5% among the Aborigines of Australia and the populations of Papua New Guinea.

© 2020 AFP