Fitness dependence of the fixation-time distribution for evolutionary dynamics on graphs

Abstract

Evolutionary graph theory models the effects of natural selection and random drift on structured populations of competing mutant and non-mutant individuals. Recent studies have found that fixation times in such systems often have right-skewed distributions. Little is known, however, about how these distributions and their skew depend on mutant fitness. Here we calculate the fitness dependence of the fixation-time distribution for the Moran Birth-death process in populations modeled by two extreme networks: the complete graph and the one-dimensional ring lattice, obtaining exact solutions in the limit of large network size. We find that with non-neutral fitness, the Moran process on the ring has normally distributed fixation times, independent of the relative fitness of mutants and non-mutants. In contrast, on the complete graph, the fixation-time distribution is a fitness-weighted convolution of two Gumbel distributions. When fitness is neutral the fixation-time distribution jumps discontinuously and becomes highly skewed on both the complete graph and the ring. Even on these simple networks, the fixation-time distribution exhibits rich fitness dependence, with discontinuities and regions of universality. Extensions of our results to two-fitness Moran models, times to partial fixation, and evolution on random networks are discussed.

arXiv comment16 pages, 7 figures, 1 table; SM: 8 pages

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Cited by in corpus (5)

• Toward a universal model for spatially structured populations
• Transient amplifiers of selection and reducers of fixation for death-Birth updating on graphs
• Game-theoretical approach for opinion dynamics on social networks
• Asymptotic absorption-time distributions in extinction-prone Markov processes
• Effect of the degree of an initial mutant in Moran processes in structured populations