FIG. 4.

Time dependence of the mutant frequency at different initial populations: purely mutant (reversion) (thicker line in upper panel), purely wild type (accumulation) (lower panel), or 50% mutant (growth competition) (dashed line). The thinner curve shows the intrapatient genetic distance T(t) during reversion. The horizontal bar is the time interval during which the base would be classified as variable (5 to 95%). Values shown in the upper left corner correspond to parameters as follows: the forward (wild type → mutant) and reverse mutation rates, μ_f and μ_r, corresponding to either A or C wild type; the replication cycle time, t_rep; and selection coefficient, s. The reversion half-time, t₅₀, is given by the equation t₅₀ = (t_rep/s)ln(s/μ_r).