Science 300 (5624): 1404-1409
Copyright © 2003 by the American Association for the Advancement of Science
Stress-Induced Mutagenesis in Bacteria
Abstract: The evolutionary significance of stress-induced mutagenesiswas evaluated by studying mutagenesis in aging colonies (MAC)of Escherichia coli natural isolates. A large fraction of isolatesexhibited a strong MAC, and the high MAC variability reflectedthe diversity of selective pressures in ecological niches. MACdepends on starvation, oxygen, and RpoS and adenosine 3\',5\'-monophosphateregulons; thus it may be a by-product of genetic strategiesfor improving survival under stress. MAC could also be selectedthrough beneficial mutations that it generates, as shown bycomputer modeling and the patterns of stress-inducible and constitutivemutagenesis. We suggest that irrespective of the causes of theiremergence, stress-induced mutations participate in adaptiveevolution.
1 INSERM U571, Faculté de Médecine Necker-Enfants Malades, Université ParisV, 156 rue Vaugirard, 75730 ParisCedex 15, France.
2 INSERM E0339, Faculté de Médecine Xavier Bichat, Université ParisVII, 16 rue Henri Huchard, 75870 ParisCedex 18, France.
3 Departamento de Ecología Evolutiva, Instituto de Ecología, Universidad Nacional Autónoma de México, Apartado Postal 70-275, México D.F. 04510, México.