Contrary to what many people believe, analysis of the virus genome reveals that it evolved naturally.
The new coronavirus SARS-CoV-2 emerged as a result of natural evolution, according to an article published in Nature Medicine. The analysis of public data of the virus genome sequence proved that the organism was not produced in the laboratory or manipulated by humans.
“By comparing the available genome sequence data for known coronavirus strains, we can firmly determine that SARS-CoV-2 originated through natural processes,” said Kristian Andersen, one of the study’s authors, in a statement.
The scientists analyzed the genetic model of spike proteins, a structure that makes up the outside of the virus and is used to grab and penetrate the cells of humans and animals. More specifically, the team focused on two important characteristics of the spike protein: the receptor-binding domain (RBD), a kind of “hook” that holds host cells to the organism, and the location of the cleavage, which works as a molecular “can opener”, allowing the virus to open and enter host cells.
The scientists found that the RBD of the SARS-CoV-2 spike proteins evolved to target ACE2, a receptor located outside human cells involved in regulating blood pressure. According to the team, the protein is so effective in binding with human cells that it can only be the result of natural evolution.
This evidence is supported by data from the SARS-CoV-2 “backbone” – its general molecular structure. For experts, if someone were trying to design a new coronavirus as a pathogen, they would have built it from the backbone of a virus already known to cause disease. The new coronavirus, however, differs substantially from microorganisms already known – and resembles mainly viruses found in bats and pangolins.
“These two features of the virus, the mutations in the RBD portion of the spike protein and its distinct backbone, rules out laboratory manipulation as a potential origin for SARS-CoV-2,” said Andersen.
The origin of the new coronavirus
Based on their analysis of genetic sequencing, Andersen and his colleagues concluded that two possible scenarios can explain the origins of SARS-CoV-2. In the first, the virus evolved into its current pathogenic state through natural selection on a non-human host and then jumped to humans. In the other scenario, a non-pathogenic version of the virus jumped from an animal host to a human one and then evolved to its current pathogenic state in the human population.
For now, experts say it is difficult to determine how the new coronavirus emerged. Still, discovering that it is the result of natural evolution is very important “to bring an evidence-based view to the rumors circulating about the origins of the virus (SARS-CoV -2) that causes Covid-19,” said Josie Golding, co-author of the study.