People with certain Neanderthal genes could be more vulnerable to COVID-19. 
Photo: dpimago/bonn-sequenza

Berlin/LeipzigThe interbreeding of Homo sapiens with Neanderthals thousands of years ago is still having knock-on effects to this day - with real health consequences. Scientists have shown that people with Neanderthal genes on chromosome 3 are up to three times as likely to suffer severe symptoms from Covid-19.

"The probability of having to be artificially ventilated in case of an infection with the novel coronavirus Sars-CoV-2 is about three times higher," researchers Hugo Zeberg and Svante Pääbo from the Max Planck Institute for Evolutionary Anthropology in Leipzig say in the current issue of 'Nature' magazine.

The probability of belonging to this risk group is relatively high in Germany. According to the researchers, one in six people in Europe has inherited the risk variant, while it is almost non-existent in Africa and East Asia.

Zeberg and Pääbo report that the variant is particularly common among people in South Asia, where about half of the population carries the Neanderthal variant in its genome.

The scientists have discovered that the DNA sequence which is the subject of the study is very similar to the DNA sequences of an approximately 50,000-year-old Neanderthal from Croatia. To be precise, it is a group of genes, also known as gene clusters.

"It has been shown that modern humans inherited this gene variant from Neanderthals when they mixed together about 60,000 years ago," explains Zeberg.

Mechanism unclear

Researchers led by David Ellinghaus from the University of Kiel had already become aware of this gene cluster in the summer. Their large-scale international study focused on chromosome 3. Zeberg and Pääbo then analysed this gene cluster at the Max Planck Institute in Leipzig  - which led them to the Neanderthals.

The Kiel study, which was published in June in the New England Journal of Medicine, attracted attention because it found that people with blood type A have a 50 per cent higher risk of developing severe Covid-19 symptoms than people with other blood types. People with blood group 0, on the other hand, were nearly 50 per cent better protected from the serious effects of infection with Covid-19.

Thanks to the Leipzig team, chromosome 3 is again of interest when it comes to Covid-19 therapies and individual risk assessment. Why people with this gene variant have a higher risk, however, is still unclear.

"The sequences in question contain interesting genes that could play a role in regulating the immune response," says Hugo Zeberg. Max Planck Institute director Pääbo finds it alarming that the genetic heritage of the Neanderthals has apparently resulted in tragic consequences during the current pandemic. He says: "We must research why this is the case as quickly as possible."

People alive today whose roots are from outside Africa carry between one and three percent Neanderthal DNA in their genomes. In Europe it's about two percent. Early humans probably mixed with Neanderthals in the Middle East about 50,000 to 60,000 years ago, when they came from Africa before spreading across Asia, Europe and the rest of the world.

Discoveries in different parts of Europe show that modern humans and Neanderthals may have lived together in Europe for up to 5,000 years and may have intermingled there. The Neanderthals became extinct 40,000 years ago.

This article was adapted from the original German version for Berliner Zeitung English Edition by Maurice Frank.