Incidentally, also strong evidence against it being a lab-strain. It’s a wild strain.
Closest related viruses: bats and Malayan pangolins
Mutation Descriptions
Polybasic Cleavage Sites (PCS): They seem to have something to do with increased rates of cell-cell fusion (increased rate of virus-induced XL multi-nucleated cells). Mutations generating PCS have been seen in Influenza strains to increase their pathogenicity, and they had similar effects in a few other viruses. So it’s not exactly increasing virus-cell fusion, it’s actually… increasing the rate at which infected cells glom into nearby cells. Fused cells are called syncytia.
O-linked glycans : Are theorized (with uncertainty) to help the virions masquerade as mucin, so hiding from the immune system. (Mutation unlikely to evolve in a lab on a petri dish)
Arguments strongly in favor of it being a wild strain
It’s not that similar to one of the known lab-strains, so it probably was wild
The “polybasic cleavage site” and “O-linked glycans” mutations would have required a very human-like ACE-protein binding site, so basically only human or ferret cells
O-linked glycans are usually evolved as an immune defense, which isn’t something cell cultures do.
Paper on some of nCOV’s mutations
Incidentally, also strong evidence against it being a lab-strain. It’s a wild strain.
Closest related viruses: bats and Malayan pangolins
Mutation Descriptions
Polybasic Cleavage Sites (PCS): They seem to have something to do with increased rates of cell-cell fusion (increased rate of virus-induced XL multi-nucleated cells). Mutations generating PCS have been seen in Influenza strains to increase their pathogenicity, and they had similar effects in a few other viruses. So it’s not exactly increasing virus-cell fusion, it’s actually… increasing the rate at which infected cells glom into nearby cells. Fused cells are called syncytia.
O-linked glycans : Are theorized (with uncertainty) to help the virions masquerade as mucin, so hiding from the immune system. (Mutation unlikely to evolve in a lab on a petri dish)
Arguments strongly in favor of it being a wild strain
It’s not that similar to one of the known lab-strains, so it probably was wild
The “polybasic cleavage site” and “O-linked glycans” mutations would have required a very human-like ACE-protein binding site, so basically only human or ferret cells
O-linked glycans are usually evolved as an immune defense, which isn’t something cell cultures do.