posted on Sep, 4 2021 @ 09:31 AM
a reply to: mikegaiser
It’s probably true but they’re definitely not sure. 2 of the 4 major coronaviruses weren’t discovered until after SARS and our shifting to
coronavirus disease research. Plus, it is highly likely that there have been several pandemic level spreads of a SARS like or other coronavirus that
we just missed because we weren’t looking or didn’t have the ability.
SARS-CoV-2 does have a unique spike, we’re still not sure where it came from aside from a bat. There is a portion of it that requires cleaving by a
protein called furin in between the S1/S2 site that really makes it get into the ACE2 receptor. It increases binding strength, speed of entry, and
helps it access the cell. It’s not required but it is the force multiplier that really helps separate it from others. The other SARS like
coronaviruses don’t have this and the animal sources we analyze don’t have it either.
We are missing that link that made it jump so much in its ability to enter its target. But it was most likely a recombination event. What happens is
there are two template sources for the genetic printer RdRp (RNA dependent RNA polymerase) to draw from. RdRp is a viral RNA copy machine protein, our
cells can’t copy RNA so the virus generates RdRp right when it enters the cell. It is notoriously inaccurate and has no capacity for error
correction like a DNA polymerase. So it bounces between the two template RNA strands from 2 different sources or viruses, and combines different
portions into a single novel strand. Usually it would be trash compared to the original and outcompeted. But every once in awhile there is one unique
brand new sequence that gives it an edge.