A study conducted by the Karolinska Institute in Sweden has revealed a unique genetic variant inherited by Europeans from Neanderthals that protects against severe COVID-19 infections. Scientists were able to identify this genetic variant by studying individuals of European and African descent. A recent study published in the journal "Nature Genetics" indicates that genes can also influence the severity of COVID-19 infections, similar to factors such as aging and asymptomatic underlying conditions like malignant cancers and silent heart attacks.
Previous research by geneticists at the Max Planck Institute for Evolutionary Anthropology primarily focused on individuals of European descent, highlighting a specific region on chromosome 12 associated with the risk of severe COVID-19. Individuals carrying this DNA segment, which contains a unique genetic variant, have a 20% lower risk of severe COVID-19 infections. This DNA segment encodes genes in the immune system, inherited from Neanderthals in about half of the individuals outside Africa.
However, this region of DNA is filled with numerous genetic variants, complicating the task of isolating the precise genetic variant that could be targeted for developing more effective treatments against severe COVID-19 infections.
Determining the Genetic Variant
Thanks to previous studies, scientists have established that we inherited this genetic variant due to interbreeding events between Homo sapiens and Neanderthals in Europe and Asia, following ancient migrations from Africa. Therefore, there is a hypothesis suggesting, "The earliest human groups in Africa did not inherit Neanderthal genes."
This hypothesis served as a good starting point for researchers in the new study, where they compared individuals of European descent with their African counterparts. If African individuals possess the genetic variant that protects against COVID-19, it would be sufficient to compare the genes located on chromosome 12 with those found in the genomes of Europeans.
With a bit of luck, the analyses from the Swedish researchers revealed that one of the genetic variants inherited from Neanderthals is also present in the genomes of African populations, leading to an estimated 20% lower risk of severe COVID-19 infections.
The scientists found that this genetic variant produces a slightly longer protein than usual, and this specific length difference appears to be the reason for its strong efficacy in limiting coronavirus replication and resisting the most virulent strains. This mechanism was initially discovered last September by a team of researchers from the University of Glasgow, but the new study reaffirms it as a basis for protection against the disease for carriers of this unique genetic variant.
The researchers emphasize the importance of including individuals from diverse backgrounds in experiments and studies, stating, "Studying only one human group would not have succeeded in identifying the genetic variant."
