Comparison between the average number of mutants from 100 stochastic simulations without replacement and the number of mutants predicted by the ODE approximation.

<p>(a) Comparing the number of mutants for a high value of the proliferation probability, <i>v</i> = 0.9. (b) Comparing the number of mutants when the proliferation probability is small, <i>v</i> = 0.1. Solid lines correspond to the number of mutants in compartment <i>C</i>_<i>i</i>, <i>i</i> = 1, …, 3, predicted by the ODE approximation and dashed lines correspond to the mean number of mutants in compartment <i>C</i>_<i>i</i> from the stochastic simulations. We assume <i>n</i> = 3, a mutation rate of <i>u</i> = 10⁻³, and the compartment sizes are <i>N</i>₀ = 1063, <i>N</i>₁ = 10⁴, <i>N</i>₂ = 10⁵, <i>N</i>₃ = 10⁶.