Does selective gene activation direct evolution?

Mechanisms may have evolved such that the unique metabolic reaction to a particular environmental stress results in higher mutation rates of those genes most likely to solve the problem. Evidence is presented indicating that the environment in effect directs the evolution of organisms by (1) presenting various kinds of stress resulting in metabolic activities that target particular genes for increased rates of transcription and mutation, and (2) selecting among this specifically enriched mutant population those variants that alleviate the imposed stress. This process should be ongoing and would be expected to accelerate the rate of microbial evolution.