Evolution with no reason: A Neutral view on epigenetic changes, genomic variability, and evolutionary novelty

Abstract

Explanations about the origin of evolutionary novelties are generally related to their adaptive value and are therefore based on ultimate causes. However, the current knowledge of genomics allows inquiry into the molecular mechanism involved in the generation of genomic evolutionary novelties, which is an approach based on proximate causes. Recent genomic evidence suggests that adaptive processes may not be as relevant as neutral (i.e., nonadaptive) processes in evolution. Based on the logic of understanding proximate causes of evolution, it is proposed here that environmentally induced germ-line epigenetic changes could be important in generating genomic evolutionary novelty. Moreover, epigenetically induced genetic variability would be in tune with the neutral theory of evolution, because this variability would be produced independent of fitness effects or adaptive value.