@alimhaider @_coltseavers 1/ That looks really interesting. The tidbit about the Yunnan mineshaft locals having antibodies in the article I posted is also interesting -- RaTG13 (4991) was the only SARS-like CoV they reported, so that virus or a close relative seems like the most obvious origin. And the
@alimhaider @_coltseavers 2/ finding that SARS-Cov-2 seems to have emerged already highly-adapted to humans, along with the failure of researchers to identify an intermediate host in the seafood market or anywhere else in the last 5 months dovetails nicely with that. So, maybe they took RaTG13 as-is,
@alimhaider @_coltseavers 3/ stuck it into a human cell bioreactor to help its evolution sometime after it was recovered in 2013, and took out news virus samples from time to time to see how the optimization was coming along. Might easily have engineered in the Furin cleavage site but my guess is that
@alimhaider @_coltseavers 4/ a long stay in a bioreactor with only human cells to grow in might well have provided sufficient selectiion pressure on its own to gain that insertion.
@alimhaider @_coltseavers 5/ Alternatively, the GOF enhancement could have been achieved in ferrets or some other animal model, or you could do a bit of both -- maybe flip back and forth between human cell culture (highest viral replication, might be possible to manipulate mutation rate) and animal
@alimhaider @_coltseavers 6/ passage -- slower evolution but would help avoid the virus losing adaptation to the whole animal and systemic immune context.
