According to the research, there is evidence that the spike protein came from the “combination” of coronaviruses that affect multiple species, not a single one.
Sars-CoV-2 may have appeared from the genetic combination and evolutionary selection of coronaviruses that target bats and pangolins. This is the conclusion of a study carried out by a group of scientists from different institutions around the world. A preprint of the study, not yet peer-reviewed, was published last Friday (29) in the journal Science Advances.
The researchers examined 43 complete genomes of three Sars-CoV-2-like coronavirus strains that target bats and pangolins. They selected the ones most similar to the new coronavirus, especially concerning the spike protein, which the virus uses to enter our cells.
Researchers have found evidence of a strong evolutionary selection around RBM, a part of the spike protein sequence that comes into direct contact with host cell receptors. According to them, these amino acids are practically identical in coronaviruses that target humans, bats and pangolins, suggesting that common evolutionary mechanisms have shaped these distinct strains.
For the scientists, the study makes it clear “that reducing or eliminating direct human contact with wild animals is critical to preventing new coronavirus zoonoses in the future,” they said in a statement. The proximity of different species in a market, for example, increases the potential for infections from one species to another, as it makes recombination between different organisms feasible.