> If memory serves, that was a single generation. An rdrp produces one error per thousand bases, which comes out to 30 mutations per generation, so we're talking 40 generations away? That hardly seems significant.
Hi I made this exact calculation (as have others). You can find it here: https://www.reddit.com/r/science/comments/gk6y95/covid19_did...
Here's an excerpt of the important bit:
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SARS-CoV-2 is mutating at the rate of about 2 changes/month (68,69,70,71), out there in society, circulating in millions of humans. 2/month in the overall population of millions of tiny viruses, among 30,000 letters in each genome.
So, at the fixation rate (~2 fixed mutations/month), with all the many billions of SARS-2 viruses making copies inside all those people, how long would it take to change RaTG-13 into SARS-CoV-2?
Answer: about 50 years. 30 years before the world even knew about SARS or MERS or any other pandemic-potential coronavirus. Before we knew these viruses even existed. Before we knew they liked to live in bats (72,73,74,75). And, for the record, they didn’t even build a BSL4 (the kind of lab you really need to handle this kind of virus in animals) in Wuhan until 2016 (76).
And that estimate (50 years) is with all the many mutations that are happening in all the many infected humans during a pandemic situation.
We know that with a smaller group of lab animals (or even human subjects), the virus is much slower at “finding” mutations that “stick around” (77,78). You have to picture it kind of like a big room full of millions of slot machines. Each machine is a virus, pulling the lever each time it makes a copy of itself. And you only win a payoff when you’ve found a change in the virus that A) makes it look different, and B) doesn’t screw it up, so it can still survive and do its job (infect people). A lot of these mutations screw the virus up, so they wouldn’t be a payoff. They wouldn’t be a “fixed” mutation.
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We can't just focus on random mutation, we have to think about fixation. Because virus populations don't just evolve in one concerted direction. They evolve /outwards/ in a cloud. It's not simply A to B, it's A to B then back to A then over to C then to D, then back to B, then over to A again, then finally settled on C. A random walk.
That's why the population level data is so important.
> How many of those are in frame for an amino acid? How many of those are two in frame for arginine in a protein, next to each other?
Who said recombination events only happen in frame? Or that viruses only drift in frame?
> There are many reasons why it's unlikely. The first is pure statistics. But the statistics are almost certainly influenced by millions of years of biology.
I would respond to this if it contained any evidence other than 'statistics say it is so.'
> I don't think it's in the scientific spirit to discount other viable hypotheses.
Who said I'm discounting anything? I said it's just not very likely. Extraordinary claims require extraordinary evidence.