Length of adaptive walk on uncorrelated and correlated fitness landscapes
Abstract
We consider the adaptation dynamics of an asexual population that walks uphill on a rugged fitness landscape which is endowed with a large number of local fitness peaks. We work in a parameter regime where only those mutants that are a single mutation away are accessible, as a result of which the population eventually gets trapped at a local fitness maximum and the adaptive walk terminates. We study how the number of adaptive steps taken by the population before reaching a local fitness peak depends on the initial fitness of the population, the extreme value distribution of the beneficial mutations, and correlations among the fitnesses. Assuming that the relative fitness difference between successive steps is small, we analytically calculate the average walk length for both uncorrelated and correlated fitnesses in all extreme value domains for a given initial fitness. We present numerical results for the model where the fitness differences can be large and find that the walk length behavior differs from that in the former model in the Fréchet domain of extreme value theory. We also discuss the relevance of our results to microbial experiments.
 Publication:

Physical Review E
 Pub Date:
 September 2014
 DOI:
 10.1103/PhysRevE.90.032703
 arXiv:
 arXiv:1406.6826
 Bibcode:
 2014PhRvE..90c2703S
 Keywords:

 87.23.Kg;
 02.50.Cw;
 02.50.Ey;
 Dynamics of evolution;
 Probability theory;
 Stochastic processes;
 Quantitative Biology  Populations and Evolution;
 Condensed Matter  Statistical Mechanics
 EPrint:
 To appear in Phys. Rev. E