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posted 02. June 2003 17:02
Science May 30, 2003
Stress-Induced Mutagenesis in Bacteria
Ivana Bjedov,1* Olivier Tenaillon,2* Bénédicte Gérard,2* Valeria Souza,3 Erick Denamur,2 Miroslav Radman,1 François Taddei,1 Ivan Matic1
The evolutionary significance of stress-induced mutagenesis was evaluated by studying mutagenesis in aging colonies (MAC) of Escherichia coli natural isolates. A large fraction of isolates exhibited a strong MAC, and the high MAC variability reflected the diversity of selective pressures in ecological niches. MAC depends on starvation, oxygen, and RpoS and adenosine 3',5'-monophosphate regulons; thus it may be a by-product of genetic strategies for improving survival under stress. MAC could also be selected through beneficial mutations that it generates, as shown by computer modeling and the patterns of stress-inducible and constitutive mutagenesis. We suggest that irrespective of the causes of their emergence, stress-induced mutations participate in adaptive evolution.
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