The Covid-19 virus has caused public anxiety and a feeling of powerlessness across the world. Since the outbreak, misinformation and false statements have been doing the rounds, including conspiracy theories that the virus is a "man-made bioweapon", reports Forbes. However, a new study, published in the journal Nature Medicine, found no evidence that the virus was created in a laboratory or otherwise engineered.
SARS-CoV-2 a product of natural evolution
Shortly after the outbreak of the novel strain of coronavirus on December 31 last year and Chinese authorities alerting the World Health Organization (WHO), Chinese scientists sequenced the genome of the Covid-19 virus – named SARS-CoV-2 – and made the data available to researchers across the world.
Researchers behind the recent study, which was published yesterday, then analysed this public genome sequence data from SARS-CoV-2, as well as related viruses, and focused in on a number of revealing features of the virus, in the hope of determining its origin and evolution. They concluded that it was the product of "natural evolution".
"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, PhD, an associate professor of immunology and microbiology at Scripps Research and one of the authors of the study.
The paper, titled The proximal origin of SARS-CoV-2, explains an analysis of the genetic template for spike proteins – the viral membrane protein responsible for cell entry. The researchers then narrowed their focus further by examining two significant features of the spike protein, explains Science Daily:
- The receptor-binding domain (RBD): this has a "grappling hook" that grips onto host cells
- The cleavage site: a molecular "can-opener" that allows the virus to crack open and enter host cells
They concluded that because the SARS-CoV-2 spike protein was incredibly effective at binding the human cells, it couldn’t have been the product of genetic engineering.
The researchers also found that the backbone (overall molecular structure) of the new coronavirus mostly resembled related 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, putting to rest speculation about deliberate genetic engineering of the virus.
Where it might have originated
Andersen and his fellow researchers considered two possible scenarios for the origin of SARS-CoV-2:
- Natural selection in an animal host before zoonotic transfer: the virus evolved to its current pathogenic (capable of causing disease) state through natural selection in a non-human host, and then jumped to humans.
- Natural selection in humans following zoonotic transfer: a non-pathogenic (incapable of causing disease) version of the virus jumped from animal host into humans, and then evolved to its current pathogenic state within the human population.
In a detailed explanation, the paper concludes with co-author Andrew Rambaut saying that it is difficult, if not impossible, to know at this point in time which of the scenarios is more likely.
However, he added that, if the SARS-CoV-2 entered humans in its current pathogenic state from an animal source, there is a high likelihood of future outbreaks. This is because the illness-causing strain of the virus could still be circulating in the animal population, and there is a chance that this might then jump to humans again.
In the event that researchers find the second scenario to be true, the chances of future outbreaks are less worrisome.