Neanderthal genes may reduce some people’s risk for severe COVID-19

• Some people have genes that are inherited from Neanderthals, which reduces their risk of severe COVID-19 by 22%.
• But the same researchers previously found that Neanderthal DNA could also put people at higher risk for respiratory failure due to COVID-19.
• The hereditary genes are more common in Europe and Asia.
• Visit the Insider Business Department for more stories.

As an emergency physician, Hugo Zeberg saw firsthand how many COVID-19 infections can differ in severity. So he started looking for answers in a place that was familiar to him: the genome of Neanderthal people.

Zeberg works at the Karolinska Institute in Sweden and has been studying for the last few years the extent to which Neanderthal humans – an extinct human species that became extinct about 40,000 years ago – transmitted genes to modern humans through crossbreeding.

Scientists think that Neanderthal DNA makes up 1% to 2% of the genomes of many people of European and Asian descent. That small fraction of humans’ genetic codes may contain important clues about our immune responses to pathogens.

In a study published this week, Zeberg and his colleague Svante Pääbo at the Max Planck Institute for Evolutionary Anthropology suggest that some people may have inherited a genetic benefit that reduces their risk of getting COVID-19 by 22%.

The benefit comes from a single haplotype – or long block of DNA – on chromosome 12. The same haplotype has been shown to protect humans against West Nile, hepatitis C and SARS (another coronavirus that has many genetic similarities to the new, SARS, Share). -CoV-2).

“The protective effect of this haplotype is probably not unique to SARS-CoV-2, but a more common part of our immune system,” Zeberg told Insider.

Some Neanderthal genes are useful, others are harmful

Reuters

Zeberg and Pääbo found that the Neanderthal-inherited haplotype could have been more common in humans over the past 1,000 years. One possible explanation for this, according to Zeberg, is the role of genes in protecting humans against other diseases caused by RNA viruses.

For their new study, the team relies on the genomes of three Neanderthals – two of which were found in southern Siberia and one from Croatia. The DNA dates back 50,000 to 120,000 years. They compared the Neanderthal genomes with the DNA of thousands of people with severe COVID-19.

The haplotype associated with less severe COVID-19 was found in all three Neanderthal genomes. It encodes proteins that activate enzymes that help break down RNA viruses.

However, a previous study by Zeberg and Pääbo, published in September, showed that not all Neanderthal DNA provides an advantage. In that study, they found that some modern humans inherited a haplotype on chromosome 3 that put them at a higher risk for respiratory failure due to COVID-19. That particular gene grouping was found in the Neanderthal from Croatia.

“If you have the variant, you have twice the risk of getting seriously ill with COVID-19 – maybe even more,” Zeberg said.

Zeberg’s research indicates that approximately 25% to 30% of people in Europe and Asia carry the protective haplotype, while up to 65% of people in South Asia and 16% of people in Europe carry the dangerous one. Unfortunately, the protective haplotype does not compensate for the danger of the dangerous for those who have both.

Revealing mysteries about how genes affect COVID-19

Nicolas Tucat / AFP via Getty Images

It seems that people in Africa mostly did not inherit any genes from Neanderthals.

“Neanderthals went to Europe and Asia and lived there before modern people,” Zeberg said. “Then modern people came 100,000 years ago and probably mixed them 60,000 years ago. So Africa has never met Neanderthals.”

However, he added that it is possible that Africans inherited other genetic variants from different ancestors that confer their own protection against COVID-19.

“There are variants in Africa that we and others are exploring,” Zeberg said.

Brendan McDermid / Reuters

Scientists still do not know how much of our disease protection was inherited from ancient ancestors compared to more recently. Finding out is complicated by the fact that part of the Neanderthal genome is still missing.

But studying ancient genes can still help reveal more about how the body responds to the coronavirus. In a December study, for example, eight sites on human chromosomes were identified where specific gene variants are more common among critically ill COVID-19 patients.

“If we can get a deeper understanding of how our evolutionary history shaped our immune system, it could be valuable,” Zeberg said.

It is possible, for example, that human ancestors relied on specific genes to protect them from viruses that have since become extinct. This may explain why some people’s immune systems overreact to the new coronavirus, which causes inflammation that can be fatal.

Zeberg said scientists have just begun to scratch the surface of these findings.