I think it is implausible that an unrelated coronavirus with a FCS would magically make itself very genetically similar to existing sarbecoronaviruses. Of course it could make itself phenotypically similar (like whales are to sharks) but the genome would look very different.
Most very large changes is viral evolution is lateral transfer between viruses, rather than accumulation of point mutations. The better claim would be that this was acquired by a proto-SARS-CoV-2 virus that way, not that it was the result of cross-species changes alone.
I appreciate you writing this post! I was curious about the evidence for lab leak, but was too lazy to investigate on my won.
You point out COVID-19 is the only sarbecovirus with furin cleavage site. But couldn’t it have evolved by switching host from some other species? According to Nature, “viruses more often evolve by jumping from one host species to another than by remaining within a particular species.”
So the general prevalence of furin cleavage sites seems relevant too. Did anyone look into what that is?
I think it is implausible that an unrelated coronavirus with a FCS would magically make itself very genetically similar to existing sarbecoronaviruses. Of course it could make itself phenotypically similar (like whales are to sharks) but the genome would look very different.
https://en.wikipedia.org/wiki/RaTG13#Phylogenetics
Most very large changes is viral evolution is lateral transfer between viruses, rather than accumulation of point mutations. The better claim would be that this was acquired by a proto-SARS-CoV-2 virus that way, not that it was the result of cross-species changes alone.