zlacker

>>todd8+(OP)
The evidence is circumstantial, but there has yet to be any evidence ruling it out. To be clear, the lab leak hypothesis is always possible. Things can always leak out of labs, let's not kid ourselves.

Some things (going by memory here) that seem to support the hypothesis:

1) Major point of differentiation for this virus is that compared to it's closest known relatives, it has acquired a furin site (eukaryotic protein cleavage site) that enhances its virulence.

2) That furin site RNA contains a non-canonical amino acid codon

3) That non-canonical codon contains a restriction site that could easily be used to track, whether, say, your added furin site is surviving multiple cell passages, by performing a restriction digest and running the fragments on a cell.

Like I said above, it's circumstantial, but this is all very normal. Both adding the furin site (how does coronavirus evolve into something more virulent?) and tracking it that way. Then all it takes is someone to get infected (EVERYONE working in biology has broken at least one lab safety rule in their life, even in BSL4) and either not be symptomatic and realize, or not say anything.

>>COGlor+lE
Furin cleavage sites very similar if not largely identical to this one have also been found in nature, and have been generated in nature in very short spans of time (on the order of a few decades, which is what is suspected to have happened with SARS-CoV-2).

I describe the evidence in detail in this detailed longform post I wrote on reddit a few months back: Hi, I have a PhD in virology focused on emerging viruses, and a few months back I wrote a very lengthy and involved piece full of sources.

And in there, I describe exactly how wrong your point 1 is. And how misguided your point 3 is.

The post also won a "best of r/science 2020" award!

You can find it here: https://www.reddit.com/r/science/comments/gk6y95/covid19_did...

See under "Addendum to Q2"

>>jedueh+u41
> Furin cleavage sites very similar if not largely identical to this one have also been found in nature

I don't believe this is correct.

There are no other examples of a CoV within the sub-genera Sarbecovirus of a species/strain that shows evidence of insertion of a polybasic furin cleavage site.

>>EMM_38+gG1
I just wanted to add that I probably was exaggerating when I said "we have no idea how that happened." re: VP40, bats, and ebola.

Best guess is: a retrovirus and an ebola-like virus infected a bat cell at the same time, the retrovirus accidentally picked up some of the bat genome, which then somehow recombined with the negative sense RNA genome of the ebola-like virus. We have no proof this happened like this, but it's the best guess.

Just as an example of the crazy things that we think probably happen in the world of viruses in nature.