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
https://www.sciencedirect.com/science/article/pii/S187350612... Here is a paper that states that the furin cleavage site appears naturally in a number of viruses.

I looked into these lab origin theories for the furin cleavage site last year. The problem with it being a laboratory insertion was that although performing an insertion is relatively easy once you know what to insert, generally it’s beyond current science to independently create mutations for a specific purpose.

It’s a bit beyond me as a non-biologist but my feeling based on the literature was that the lab origin was unlikely. However it is pushed in certain circles partly for ideological reasons, based on evidence that is plausible at first glance but with a lot more digging not entirely convincing evidence.

However, there didn’t really seem to be much neutral expert analysis of the evidence.

>>ximeng+ky
The natural origin hypothesis is also pushed for ideological reasons - at this level of meta analysis we are at a stalemate. The article was good at revealing that there is not just ideology - but also material interests involved and that the two prestigious letters that were so categorical in dismissing the lab escape hypothesis were quite a bit tainted by conflicts of interests.

>>zby+PB
My colleague, an evolutionary biologist's comment on this: the virus is unlikely to prevail if manually tweaked since evolution does such an amazing job that it's very unlikely it alone could dominate and infect large populations.

>>dumb12+2M
How about a virus that's just allowed to evolve inside human tissue? Not "manually tweaked" just allowed to evolve faster.

>>zpeti+rx3
I'm not an evolutionary biologist. I merely want to pass on his comment. He studied the viral genome segments inserted in human genome. I can pass that question to him if you want.

>>dumb12+wN3
The Coronavirus Gain-Of-Function research the Wuhan lab was doing probably wasn't manually tweaking the virus, or inserting viral genome segements.

It was more likely putting evolutionary pressure on Coronaviruses in order to change it's properties and behaviour.

>>Closi+Fd5
'Manually tweak' is a bad word invented by me. He didn't mean it was viral segment insertion either.

Regarding selection pressure people do that all the time, in fact it is far from easy to artificially apply environmental pressure and obtain highly functional new variants. In cancer research, xenograft are extremely tricky to do with immunodeficient animal models, let alone human tissue in the lab. Sure you can have some success but it's difficult enough to reproduce. His point is that even if an artificially selected highly viable variant was obtained, it is very unlikely it can prevail in real world nature selection (large scale too). I'm no expert but happy to read about any paper if it's not the case.