20 MAY 2011 by ideonexus
Genes are Under Constant Attack
Every animal and plant genome is subject to a constant bombardment of deleterious mutations: a hailstorm of attrition. It is a bit like the moon's surface, which becomes increasingly pitted with craters due to the steady bombardment of meteorites. With rare exceptions, every time a gene concerned with an eye, for example, is hit by a marauding mutation, the eye becomes a little less functional, a little less capable of seeing, a little less worthy of the name of eye. In an animal that lives i...Constantly bombarded by things that mutate them so that the moment the expression is no longer used, it becomes ruined, thus we have blind animals living in caves.