A long stretch of DNA inherited from an interbreeding event with Neanderthals some 60,000 years ago has been linked to increase risk of severe COVID-19.
AsianScientist (Oct. 28, 2020) – While age and co-morbidities are known to influence the severity of COVID-19, research from the Okinawa Institute of Science and Technology Graduate University (OIST) in Japan has now found that leftover Neanderthal DNA also has an impact. These findings have been published in Nature.
Since first appearing in late 2019, the novel virus, SARS-CoV-2, has had a range of impacts on those it infects. Some people become severely ill with COVID-19 and require hospitalization, whereas others have mild symptoms or are even asymptomatic. Research by the COVID-19 Host Genetics Initiative has shown that genetic variants in one region on chromosome 3 impose a larger risk that their carriers will develop a severe form of the disease. In the present study, scientists have found that this genetic region is almost identical to that of a 50,000-year old Neanderthal from southern Europe.
“It is striking that the genetic heritage from Neanderthals has such tragic consequences during the current pandemic,” said Professor Svante Pääbo, who leads the Human Evolutionary Genomics Unit at OIST.
The identified genetic region is very long—spanning 49.4 thousand base pairs—and the variants that impose a higher risk to severe COVID-19 are strongly linked; if a person has one of the variants then they’re very likely to have all thirteen of them. Variants like these have previously been found to come from Neanderthals or Denisovans, so the researchers decided to investigate whether this was the case.
They found that a Neanderthal from southern Europe carried an almost identical genetic region whereas two Neanderthals from southern Siberia and a Denisovan did not.
Next, they questioned whether the variants had come over from Neanderthals or had been inherited by both Neanderthals and present-day people through a common ancestor. If the variants had come from interbreeding between the two groups of people, then this would have occurred as recently as 50,000 years ago. Whereas, if the variants had come from the last common ancestor, they would have been around in modern humans for about 550,000 years.
Because the variants between the Neanderthal from southern Europe and present-day people were so similar over such a long stretch of DNA, the researchers concluded that it was much more likely that they came from interbreeding.
The researchers also found that there are major differences in how common these variants are in different parts of the world. In South Asia, about 50 percent of the population carry them. However, in East Asia they’re almost absent. It is not yet known why the Neanderthal gene region is associated with increased risk of becoming severely ill.
“This is something that we and others are now investigating as quickly as possible,” said Pääbo.
The article can be found at: Zeberg & Pääbo (2020) The Major Genetic Risk Factor for Severe COVID-19 is Inherited from Neanderthals.
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Credited to: Asian Scientist Magazine