Abstract
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.
Publication types
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Research Support, Non-U.S. Gov't
MeSH terms
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Adaptation, Physiological
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Air Microbiology
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Alleles
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Animals
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Bacterial Proteins / genetics
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Bacterial Proteins / metabolism
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Biological Evolution*
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Computer Simulation
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DNA Repair
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DNA-Directed RNA Polymerases / genetics
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Escherichia coli / classification
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Escherichia coli / genetics*
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Escherichia coli / growth & development
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Escherichia coli / physiology*
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Escherichia coli Infections / microbiology
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Escherichia coli Proteins / genetics
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Escherichia coli Proteins / metabolism
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Feces / microbiology
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Gene Expression Regulation, Bacterial
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Genes, Bacterial
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Geologic Sediments
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Humans
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Lac Operon
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Models, Biological
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Mutagenesis*
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Oxidative Stress
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Oxygen / metabolism
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Phenotype
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Phylogeny
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Rec A Recombinases / metabolism
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Regulon
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SOS Response, Genetics
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Selection, Genetic
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Sigma Factor / genetics
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Sigma Factor / metabolism
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Water Microbiology
Substances
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Bacterial Proteins
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Escherichia coli Proteins
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Sigma Factor
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sigma factor KatF protein, Bacteria
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Rec A Recombinases
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DNA-Directed RNA Polymerases
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RNA polymerase beta subunit
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Oxygen