3 ms·

I suppose if people were inserting furin cleavage sites specifically into the Sars-CoV-2 precursor sequence, then they might generate a series of variants to se

I suppose if people were inserting furin cleavage sites specifically into the Sars-CoV-2 precursor sequence, then they might generate a series of variants to see which one worked best when it came to results of infectivity tests in human cell lines? Regarding bat lineages and host viruses, this 2019 paper seems to indicate that the other betacoronavirus lineage with the furin site, the Merbecovirus, has a different bat host range from the Sarbecovirus lineage that gave rise to Sars-CoV-2: https://www.mdpi.com/1999-4915/11/2/174 https://www.mdpi.com/1999-4915/11/2/174 "Compared to Sarbecovirus and Nobecovirus, the bat hosts that harbor viruses from the Merbecovirus sub-genus are more diverse. This is in line with the presence of more CoV species belonging to Merbecovirus." (I generally trust papers on this evolutionary origin stuff published before the pandemic a bit more than those published after, as there might be less conflicts-of-interest issues).

anonymouskimmer 4y ago
> I suppose if people were inserting furin cleavage sites specifically into the Sars-CoV-2 precursor sequence, then they might generate a series of variants to see which one worked best when it came to results of infectivity tests in human cell lines? This makes sense. I think here's the most relevant quote from that article: "So far, no betaCoVs from the sub-genus Merbecovirus have been detected in bats of suborder Yinpterochiroptera." While the paper does mention one member of Yangochiroptera (Chaerephon plicatus) that has been discovered infected with sarbecoviruses, it looks like there's little room for infectious overlap of merbecoviruses and sarbecoviruses (which predominantly infect Yinpterochiropterans, at least as detected as of the paper publication). So if the SARS-CoV-2 progenitor did get its furin cleavage site from a co-infection with a merbecovirus, this would have been a really rare event indeed. At least if the co-infection happened in a bat species, and not in another animal or a human who deals with bats.

anonymouskimmer 4y ago

> I suppose if people were inserting furin cleavage sites specifically into the Sars-CoV-2 precursor sequence, then they might generate a series of variants to see which one worked best when it came to results of infectivity tests in human cell lines? This makes sense. I think here's the most relevant quote from that article: "So far, no betaCoVs from the sub-genus Merbecovirus have been detected in bats of suborder Yinpterochiroptera." While the paper does mention one member of Yangochiroptera (Chaerephon plicatus) that has been discovered infected with sarbecoviruses, it looks like there's little room for infectious overlap of merbecoviruses and sarbecoviruses (which predominantly infect Yinpterochiropterans, at least as detected as of the paper publication). So if the SARS-CoV-2 progenitor did get its furin cleavage site from a co-infection with a merbecovirus, this would have been a really rare event indeed. At least if the co-infection happened in a bat species, and not in another animal or a human who deals with bats.