As COVID-19 has hitchhiked around the globe,causing lockdowns, pneumonia and fear, scientistshave been racing to determine where the SARS-CoV-2 coronavirus has come from.
While we don't have all the answers yet - includingwhether it came from an animal reservoir - a newanalysis has definitively put to rest the conspiraciesthat claim it's a lab-made disease.
The study raises some interesting possibilities regarding the origin of the new coronavirus. Oneof the scenarios suggests the virus may have been circulating harmlessly in human populationsfor quite a while before it became the pandemic that's now stopped the world in its tracks.
"It is possible that a progenitor of SARS-CoV-2 jumped into humans, acquiring [new genomicfeatures] through adaptation during undetected human-to-human transmission," the teamfrom the US, UK and Australia writes in the study.
"Once acquired, these adaptations would enable the pandemic to take off and produce asufficiently large cluster of cases."
The researchers analysed genomic data available from SARS-CoV-2 and other similarcoronaviruses, showing that the receptor-binding domain (RBD) sections of SARS-CoV-2 spikeproteins were so effective at binding to human cells, they had to be caused by naturalselection.
"By comparing the available genome sequence data for known coronavirus strains, we canfirmly determine that SARS-CoV-2 originated through natural processes," said one of theresearchers, immunologist Kristian Andersen at Scripps Research.
"Two features of the virus, the mutations in the RBD portion of the spike protein and itsdistinct backbone, rules out laboratory manipulation as a potential origin for SARS-CoV-2."