[Houshalter]

Evolvability can also evolve away too. For instance, a gene that decreases the mutation rate to 0. Most mutations are harmful, so any organism with the gene will be more likely to have successful children. And eventually the gene will become dominant and there will be no more mutations. And evolution will stop.

[vanderZwan]

What you say is fairly hypothetical, since the way genetics works at a fundamental level prevents this possibility.

You are also oversimplifying by not distinguishing local and global success. Locally, this gene will be successful. Globally, some mutations will be beneficial, and the children with those mutations will be more successful.

The gene may become "dominant" (and then gain the beneficial mutations through sexual reproduction), but it will not achieve a monopoly and not remove the existence of evolution.

It is somewhat comparable to why some people are left-handed[0].

However, what you allude to is basically the necessity of evolution of forms of "error correction" against mutations for complicated organisms. Sex plays a large part in that as well[1]. And interestingly, DNA repair, another involved mechanism, may actually help evolvability[2].

[0] https://www.youtube.com/watch?v=TGLYcYCm2FM

[1] https://www.quantamagazine.org/missing-mutations-suggest-a-r...

[2] https://www.quantamagazine.org/beating-the-odds-for-lucky-mu...

[Houshalter]

It's not hypothetical. We haven't observed it in nature because any organism that evolved this would simply go extinct. But similar "evolving to extinction" phenomenons have been observed. Such as genes in mice that make the entire population male, or transposons in plants: http://lesswrong.com/lw/l5/evolving_to_extinction/

>it will not achieve a monopoly and not remove the existence of evolution.

Yes it will. It's easy to do simulations. Statistically the children of the organism with less mutations will have an advantage. Eventually the gene will reach 100% of the population. The population will stop evolving and eventually go extinct.

[vanderZwan]

To be clear on this: I agree with almost all of your reasoning (in this and the previous post), but this is not exactly the most convincing way to open your counter-argument:

> It's not hypothetical.

> We haven't observed it in nature

Also, the fact that in the long term such a mutation would cause a population to go extinct eventually is not really evidence that we should not find this in the wild, because it would still be effective in the short term. Look at that recent story about the mutated lobster taking over the waters of Germany for an example.

Anyway, the crucial disagreement lies here:

> It's easy to do simulations.

Yes, if a gene would evolve that brings the mutation rate to zero, this simulation works. But achieving such a thing sounds a lot like beating the laws of thermodynamics and stopping entropy from increasing. And sure, reducing entropy locally is possible by globally increasing it - in this case that would mean increasing the energy/resource budget spent on it, but I suspect that this in itself will be at a cost too high to give an advantage.

I basically don't believe (and I fully admit that this is a subjective point of view) that the "easy simulations" are noisy, large or complex enough to reflect the messy biological reality here. Essentially, there's too much approximation going on.

And btw, evolving to extinction is not the same thing: a gene that makes the entire population male is not in itself advantageous like reducing mutations is. It is more generic than the "mutation rate zero"-gene scenario, the latter is basically a specific hypothetical example of it.