Natural Selection and Mutability

Abstract

In sexual organisms, alleles increasing the mutation rate of the entire genome are invariably selected against, whereas in asexual organisms such "general mutators" are favored if they adjust the mutation rate closer to an optimum balancing the advantages of responsiveness to environmental change against those of a small mutational load. Unless very small selective pressures are effective, it seems that no mechanisms exist to establish optimum mutation rates in sexual organisms.