[A] small fragment of the genetic code that has been inherited by modern humans from Neanderthals could carry the secret of why some people succumb to a severe form of COVID-19 requiring hospitalization, while others recover.
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The team of researchers explained that this particular genetic variant found on chromosome 3 has a low rate of recombination or change and has been handed down from our ancestors. They wrote that this genetic variant, or “haplotype,” “entered the human population by gene flow from Neandertals or Denisovans that occurred some 40,000 to 60,000 years ago.”
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This gene was a significant risk factor for severe SARS-CoV-2 infection and hospitalization. This gene fragment of 49.4 kb size was inherited from the Neanderthals and occurred in around 30 percent of the South Asian population and 8 percent of the European population. In Bangladesh, for example, 63 percent carry at least one copy of this risk factor gene. In East Asia, the gene is present in around 4 percent of individuals, the team wrote. It is absent in African populations, they added.
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Hugo Zeberg, the lead researcher on the study, said that the evolutionary story behind this inheritance is not clear, saying, “That’s the $10,000 question.” He said that this segment could be responsible for a better immune system among those in South Asia and could have been inherited.