Generation of genetic diversity by DNA rearrangements in resting bacteria

Transpositional DNA rearrangements importantly contribute to the genomic plasticity of bacteria, their viruses and plasmids. Interestingly, enzymatically mediated transposition is not limited to propagating bacteria, but it also occurs in prolonged periods of rest. As revealed with RFLP analysis, genetic polymorphism increases steadily upon storage of bacteria in the resting phase. These results are discussed here in the wider context of accumulating knowledge on molecular mechanisms contributing to overall spontaneous mutagenesis, which is the result of a multitude of specific, often enzyme-mediated processes of variation generation.