Tuesday, July 25, 2006
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Evolution: Bacterial Mutation in Stationary Phase
Paul Sniegowski, Current Biology, March '04
Department of Biology, University of Pennsylvania, Philadelphia, Pennsylvania 19104, USA
A recent study indicates that the genomic mutation rate of the gut bacterium Escherichia coli is substantially higher in nongrowing than growing cultures. These findings are important in the light of the ongoing controversy over the generality and robustness of stationary phase mutagenesis and its evolutionary implications.
Article Outline begins:
The genomic mutation rate is a fundamental evolutionary parameter of any population, determining the rate of influx of new deleterious and beneficial alleles. Because most mutations are likely to be harmful to fitness, DNA repair and proofreading systems have probably evolved so as to minimize rates of mutation. Even the microbial extremophiles that normally inhabit harsh and potentially mutagenic environments seem to have low genomic mutation rates, suggesting that selection almost always puts a premium on the faithful maintenance and transmission of genetic information. Nonetheless, geneticists have long known that some environmental extremes can elevate mutation rates; indeed, this is the basis for the use of DNA damaging agents to induce mutations for study.
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