zlacker

>>todd8+(OP)
> The virus does have an inexplicable feature: a so-called “furin cleavage site” in the spike protein that helps SARS-CoV-2 pry its way into human cells. While such sites are present in some coronaviruses, they haven’t been found in any of SARS-CoV-2’s closest known relatives.

This is false. First of all it should be stated clearer that there has been parallel evolution across several branches of coronaviruses which have independently evolved a furin cleavage site (so there is evolutionary pressure and advantage for coronaviruses to follow this path):

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

And then the statement is just wrong. The related sarbecoviruses found in Thailand have similar furin cleavage sites:

> The RacCS203 S gene is most similar to that of RmYN02 (Supplementary Fig. 3a). The two viruses shared part of the furin cleavage site unique to SARS-CoV-2 (Supplementary Fig. 3b) and have an almost identical RBD aa sequence with only two residue differences out of 204 aa residues

https://www.nature.com/articles/s41467-021-21240-1

>>lamont+UZ
I have to nitpick. I don't believe there's evolutionary pressure to evolve this. Evolution is (going to piss some people off) almost entirely random. There may be purifying selection but that has an entirely different set of properties than the idea of Lamarckian evolution.

Edit: Perhaps to clarify, what I'm trying to say is that evolution does not have foresight. And this is not my opinion, but merely that of Eugene Koonin, and I'm just repeating it.