Jacob Kimmel

And this explains a whole lot.

If you look at most genes in the genome, they actually arise at least at some point in evolution from a duplication event.

So that means you've got gene A, it's doing, you know, it's performing some job, and then some new environmental concern comes along.

Maybe it's like a lack of particular source of nutrient.

Maybe it's a pathogen challenging you.

And maybe gene A, if it were to dedicate all of its energies, so to speak, you were to mutate it to solve this new problem, could be adapted with a minimal number of mutations.

but then you lose its original function.

So we have this nice feature of the genome, which is it can just copy and paste.

And so occasionally what will happen in evolution is you get a copy paste event.

Now I've got two copies of gene A and I can preserve my original function in the original copy.

And then this new copy can actually mutate pretty freely because it doesn't have a strong selective pressure on it.

So most mutations might be null.

I've got two copies of the gene.

I can have lots of mutations in it accumulate.

Nothing bad really happens because I've got my backup copy, my original.

And so that you can end up with drift.

It's not that the base rate goes up.

It's not like DNA polymerase is more erroneous or that you're just like doubling it.

It's not like, oh, well, I've got two copies.

That is true, but I don't think it's the main mechanism.