BecomeMe

Fish get fat, blind, and long-lived in just a few generations after you put them in a cave.

This implies that evolution isn't creating these traits out of nothing, but that fish either have fat-blind-long-lived genes that don't express unless they're in the appropriate environment, or that the environment is causing them to become that way without genetic changes.

They did some experiments that imply that the effect is caused by genetics, not just the environment, and suggest that human beings may have longevity genes that just aren't being expressed.