Figure 3. The mutational fitness distribution.
The stochastic process governing the evolution of fitness values of cells within a compartment depends on the shape of the fitness distribution conferred by mutations. For simplicity, we consider a general family of fitness distributions determined by the shape parameters α and β, which govern the decay of advantageous and deleterious mutations, respectively. This flexible setup allows us to study the effects of varying the mutational fitness distribution on the dynamics of cancer initiation. As specific examples, the figure displays the probability density function of fψ for α = 0.5 and β = 0.4, 0.5, 0.6.