I'll listen to the podcast of the journalist posted earlier (VF hits a paywall for me). I have followed the story but from my own angle. If there was some sort of deliberate engineering-which is what's ultimately implied by the gain of function stuff-it would be hard to do it without leaving traces in the viral genome sequence. If there is a signature, what is it? The CoV-2 genome has been scrutinized pretty hard at this point. If it is of natural origin, tracking the phylogeny should be able to reconstruct the lineage, although it is admittedly a difficult task-looking for strains in bats and other beasties spread all over the place. If it was a normal recombinant that arose from strains isolated in the wild and brought to Wuhan, with somebody screwing up and getting themselves infected, we may never learn of the event, unless our intelligence agencies have something definitive that has yet to see the light of day. Ultimately, for the biology, either two coronaviruses got together and recombined as they tend to do, either in a culture dish or in nature, or....not. If it's a recombinant it would be really great to know the parental strains. Solid evidence could come from intelligence or good muckraking journalism, although you could just get smoke and mirrors, which I think is pretty much where its at. But if you could see it or find it, the real answer must be embedded in viral genomes.