Figure 3.

The average fraction of mutants conditioned upon no extinction. Our analytical approximation equation (2.7) is good for up to N/4 generations, in contrast to the approximations for the probability of extinction, which holds only for a single generation (cf. figure 2). For longer times, the fraction of mutants increases at a slower rate, reaching the maximum N after approximately 2N generations, which is consistent with the average conditional fixation time of the neutral mutants. The distribution becomes broader with time, but narrows again when almost all realizations have reached fixation, as illustrated for the case of N = 10 (error bars represent the standard deviation obtained from averages over 10⁶ independent realizations). (Online version in colour.)