People who survive an episode of Covid-19 with mild symptoms or even no symptoms at all can thank their Neanderthal ancestors. They carry a genetic mutation that reduces the risk of serious infection.
- A genetic mutation present in Neanderthal DNA reduces the risk of serious Covid-19 infection by 22%.
- The genetic region involved affects the body’s immune response to RNA viruses, such as coronavirus or hepatitis C or West Nile virus.
- This discovery could explain why some patients are harder hit by the virus than others, especially black-skinned patients, the researchers say.
Thank you Neanderthal! German researchers have discovered a genetic mutation present in the DNA of this branch of our ancestors which reduces the risk of serious Covid-19 infection by 22%. This mutation was also seen in approximately 30% of samples from people of European and Asian descent. These results were published on January 22 in the PNAS.
Chromosome 12 involved
The genetic region involved affects the body’s immune response to RNA viruses, such as coronavirus or hepatitis C or West Nile virus. “This region codes for proteins that activate important enzymes during infections with RNA virusesthe researchers said. A haplotype on chromosome 12 is associated with an approximately 22% reduction in the relative risk of becoming seriously ill with Covid-19 when infected with SARS-CoV-2, is inherited from Neanderthals.” The haplotype is present in all regions of the world but is “in populations of Eurasia and the Americas at carrier frequencies that reach and often exceed 50%”, add the scientists.
This discovery could explain why some patients are harder hit by the virus than others, especially black-skinned patients, the researchers say. “Neanderthals, who died out around 40,000 years ago, lived alongside modern humans and sometimes encountered them in Europe and Asia but not Africa, and people of purely African descent do not carry Neanderthal DNA”, continue the team of scientists. Previous studies have revealed that between 1 and 5% of our modern DNA comes from Neanderthals.
Another Neanderthal gene favors severe forms
For the study, the researchers used samples taken from more than 2,200 people with severe cases of Covid-19 infection. They first discovered a genetic region that affects susceptibility to severe disease. Next, they checked DNA taken from the skeletons of four ancient humans – a 70,000-year-old Neanderthal from Siberia, a 50,000-year-old Neanderthal from Croatia, a 120,000-year-old Neanderthal from Denisova Cave in Siberia, and a dating back 80,000 years. They found that all four samples carry the same versions of this genetic sequence.
Last year, the same team of researchers discovered that other genes from Neanderthals would, on the other hand, increase the risk of serious illness. This is chromosome 3 which would multiply by three the risks of developing a severe form of respiratory distress. This fragment is present in 50% of the population of South Asia, in 16% of Europeans but almost absent in African populations.
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