High mutation rates are thought to drive populations to extinction through the build-up of harmful genetic changes. This is not necessarily so, according to a new experiment.
James Bull and his colleagues at the University of Texas at Austin exposed a type of virus called a T7 bacteriophage to a toxin that increased its mutation rate by 2–3 orders of magnitude, to about four mutations per genome each generation. After 200 generations, the virus's fitness had increased, rather than decreasing as expected. The genomes were riddled with hundreds of deleterious mutations, but 28 adaptive mutations, mostly in DNA-metabolism genes, reached high frequencies.
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Evolutionary genetics: Mutation elevation. Nature 462, 14–15 (2009). https://doi.org/10.1038/462014f
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DOI: https://doi.org/10.1038/462014f
