Natural Selection and the Emergence of a Mutation Phenotype: An Update of the Evolutionary Synthesis Considering Mechanisms that Affect Genome Variation
Caporale, Lynn Helena
Most descriptions of evolution assume that all mutations are completely random with respect to their potential effects on survival. However, much like other phenotypic variations that affect the survival of the descendants, intrinsic variations in the probability, type, and location of genetic change can feel the pressure of natural selection. From site-specific recombination to changes in polymerase fidelity and repair of DNA damage, an organism's gene products affect what genetic changes occur in its genome. Through the action of natural selection on these gene products, potentially favorable mutations can become more probable than random. With examples from variation in bacterial surface proteins to the vertebrate immune response, it is clear that a great deal of genetic change is better than "random" with respect to its potential effect on survival. Indeed, some potentially useful mutations are so probable that they can be viewed as being encoded implicitly in the genome. An updated evolutionary theory includes emergence, under selective pressure, of genomic information that affects the probability of different classes of mutation, with consequences for genome survival.