zlacker

>>datafl+(OP)
There is an interesting peer reviewed paper published last month with analysis of existing facts about the origin of covid-19. A part from their conclusion:

More than a year after the initial documented cases in Wuhan, the source of SARS-CoV-2 has yet to be identified, and the search for a direct or intermediate host in nature has been so far unsuccessful.

The low binding affinity of SARS-CoV-2 to bat ACE2 studied to date does not support Chiroptera as a direct zoonotic agent. Furthermore, the reliance on pangolin coronavirus receptor binding domain (RBD) similarity to SARS-CoV-2 as evidence for natural zoonotic spillover is flawed, as pangolins are unlikely to play a role in SARS-CoV-2′s origin and recombination is not supported by recent analysis.

At the same time, genomic analyses pointed out that SARS-CoV-2 exhibits multiple peculiar characteristics not found in other Sarbecoviruses.

A novel multibasic furin cleavage site (FCS) confers numerous pathogenetically advantageous capabilities, the existence of which is difficult to explain though natural evolution...

source: https://link.springer.com/article/10.1007/s10311-021-01211-0

>>novaRo+ep
> "Furin cleavage sites naturally occur in coronaviruses"

> https://www.sciencedirect.com/science/article/pii/S187350612...

They exist in the human HCoV-HKU1, HCoV-OC43, MERS-CoV and appear to have evolved independently at least 6 times in betacoronaviruses.

Furthermore while this article claims that the furin cleavage site has not found in any sarbecoviruses, that is now outdated information:

> "Evidence for SARS-CoV-2 related coronaviruses circulating in bats and pangolins in Southeast Asia"

> https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7873279/

Both RacCS203 (91.5% similar to SARS-CoV-2) and RmYN02 (93.3% similar to SARS-CoV-2) have furin cleavage sites. So we're up to 7-to-9 times now that evolution has evolved a furin cleavage site in betacoronaviruses, including 3 sarbecoviruses that may or may not be directly related.

The whole "furin cleavage site is an indication of human engineering" argument is just falsified at this point.

>>lamont+FD1
What's your estimate of the relative prevalence of an FCS among the likely space of lab-created SARS-like coronaviruses vs. among natural, SARS-like coronaviruses? My understanding is that adding an FCS is a very common method of lab gain of function, but rare among such viruses in nature.

I don't think the FCS is determinative, and I agree Wade's article overstates its significance. In a Bayesian analysis, it still seems to me like it points weakly (at least 3x prevalence?) towards lab origin, though.