Evolution of the mutation rate.

<p>Ancestral genomic mutation rates are shown as squares, evolved mutation rates at generation 3000 as circles, and 95% confidence intervals of mutation rate estimates are shaded. Each evolved strain's mean change in mutation rate is shown as the percentage of its ancestor's mutation rate. Data from MR^S strains are shown in blue, from MR^M strains in yellow, from MR^L strains in orange, and from MR^XL strains in red.