CIDRAP Contrary to prevailing belief, an evolutionary analysis finds no evidence that most viruses with epidemic or pandemic potential that jumped from animals to people were shaped by selection in a lab or prolonged evolution in an intermediate host—challenging claims that SARS-CoV-2, the virus that causes COVID-19, was engineered in a lab.
A University of California (UC) San Diego–led research team analyzed viral genomes to characterize natural selection under the hypothesis that zoonotic viruses (Ebola, Marburg, mpox, influenza A, and SARS-CoV-2) need to adapt before infecting people and achieving sustained human-to-human spread. They focused on the evolutionary period right before outbreaks, when viruses would be expected to leave detectable traces of any substantial adaptation.
The researchers validated their approach using known examples of artificially selected viruses grown in cell culture or lab animals, which showed clear and reproducible evolutionary footprints distinct from natural transmission.
The findings were published late last week in Cell.