Figure 1

Error threshold The minimum permissible replication accuracy per base (q_min) is plotted against λ for three different ways of the calculation. The solid line is obtained from the additive assumption and the binomial approximation (Eq. 3). The binomial approximation is threatened at a high error rate. To examine this, the error threshold is calculated without the binomial approximation (but with the additive assumption) in the extreme example, where the binomial approximation deviates most (see the text). Let N _δ be the sum of the sequence length of the parts where all single mutations are deleterious. Then q_mim is calculated as . The dotted line represents the so calculated error threshold in this extreme example. The x-axis for the dotted line (i.e., λ) is calculated as (N - N _δ )/N. The dashed line is obtained from the formulation of Reidys et al. [5] (Eq. 5). In all cases, N = 100 and σ = 10. (The same values of N and of σ as those used in [5] are chosen for a comparison purpose.)