Evolutionary drift


Evolutionary driftsearch for term

The accumulation of sequence differences that have little or no impact on the fitness of an organism; such neutral mutations are not under selection. Sequence polymorphisms arise randomly in a population, most of which have no effect on function. Stochastic processes allow a small fraction of these to increase in frequency until they are fixed in a population; these are detectable as neutral substitutions in interspecies comparisons. (Hardison 2003)