A research team from the US has gone through the viral genome of the coronavirus and found out that it results from bat viruses' recombination with a contribution from pangolin viruses as well.
They have determined that the virus is a result of the normal genetic process of recombination. In the process, mixing up pieces of RNA strands to form a distinct genetic combination took place to create what is now called SARS-CoV-2.
The findings of the study were published in the journal Science Advances on May 29, 2020.
The Coronavirus Genome
Professor Zhang Yongzhen and his team were the first ones to release the genome sequence of the coronavirus into the world back in January. A day after publishing their work on open platforms, their laboratory at the Shanghai Public Health Clinical Centre was forced to close for "rectification" purposes. The release of the virus' genome sequence tremendously helped many researchers develop test kits, which are now used to detect the virus.
The coronavirus genome is a single, long RNA molecule. The enzyme that duplicates the RNA genome goes down it from one end to the other, making a copy as it goes. A significant advantage here is that researchers now have a lot of coronavirus sequences from various hosts obtained in public databases.
For the new study, the team began with a collection of 43 different coronaviruses from various species. These included humans, bats, and the pangolin sequences similar to SARS-CoV-2.
The underlying genome investigation confirmed that SARS-CoV-2 is most closely associated with many viruses that had been secluded in bats. However, various areas of the virus were more or less related to other bat viruses.
More Epidemics to Come?
Furthermore, the researchers found that a vital stretch of the spike protein came from a pangolin version of the virus through the recombination process. These proteins are the ones responsible for determining which proteins on human cells it merges with.
Moreover, the researchers believe that both ideas from earlier work proved to be correct. SARS-CoV-2 is most closely related to bat viruses as well as pangolin viruses. According to the authors, it just depends on which angle in the genome you look at.
The sequences of the virus tell a story about a giant natural experiment presently going on around us. Scientists discover that there appears to be a considerable amount of coronaviruses that are routinely exchanging genetic information.
The authors find evidence that the viruses from different species may go through distinct selective pressure, but can also produce hard-to-predict results when those viruses transfer to a new species.
In conclusion, the researchers say there seem to be a plethora of coronaviruses out there, plenty of which are still unknown to humans. Some species are acting as labs in which new genetic combinations are concocted. As of present, only a partial window is made open to scientists in knowing the potential in which species have frequently come in contact with humans.
Additionally, some research noted by the authors suggests that there have been instances where humans have been exposed to at least some of these viruses based on their antibodies. Fortunately, the exposure was not enough to cause a major outbreak of disease. Finally, the study's findings suggest that future pandemics are a question of "when," rather than "if."
