[benkuhn]

I'm not an evolutionary biologist, but it seems to me that the claimed magnitude of the change is wildly implausibly fast from an evolutionary perspective. I'm confused that neither the article, nor the paper it cites, addresses this.

To go from 10% to 30% in ~5 generations, the median-artery-having population would have had to expand by (30/10)^(1/5) = 25% more than the non-median artery population over each generation. It just seems totally implausible that median artery carriers could have that much more offspring.

This makes me pretty suspicious that the paper may be wrong.

[rixed]

You could also suspect that your understanding of evolution is not 100% correct.

Genes do not necessarily propagate in a population because they enhance reproduction. They can have no or very little influence but still propagate by chance. (Similarly, beneficial mutations can disappear from the genetic pool by chance). Lookup "genetic drift".

By the time the environment does change (which can happen as quick or slow as one wants), the lucky genes are already spread in the population and may turn useful or detrimental to the individuals after that environmental change.

Also, genetics is not the only driver for evolution.