Evolution-driving genes.
Genomic sequences provide evidence for a common origin of life and its evolution via selection of genetic variants created by mutation and recombination. Two classes of genes are known to accelerate mutation and/or recombination rates in bacterial populations: stress-inducible wild-type genes, usually part of the SOS regulon, and genes whose functional loss, or downregulation, increases the rate of genetic variability (mutator and/or hyper-rec mutants).