Fig 4. Average clone mass is set by mutation-expansion balance.

The ensemble-averaged final mass of mutant clones 〈X〉 as measured from 1D simulations as a function of rescaled mutation rate, scaled by the expected dependence ($\propto 1/\sqrt{\tilde{u}}$) for wavelike growth of clones. Results from different system sizes (symbols) are presented for each dispersal kernel quantified by μ (colours); the values are (from top to bottom) μ = {0.2, 0.6, 0.8, 1, 1.2, 1.4, 1.6, 1.8, 2, 3}. Each point represents an average over 20 or more independent simulations. Error bars denote measured standard deviation across repetitions. Dashed lines show the theoretical predictions for $\chi \left(\tilde{u}\right)$ for each dispersal kernel (see S1 Appendix, Section A for details), multiplied by a μ-dependent magnitude factor whose value is 1.5 for 1 ≤ μ < 2, 1.6 for μ > 2, and 1.65 for all other values.