Recombination and mutational robustness in neutral fitness landscapes

Abstract

Mutational robustness quantifies the effect of random mutations on fitness. When mutational robustness is high, most mutations do not change fitness or have only a minor effect on it. From the point of view of fitness landscapes, robust genotypes form neutral networks of almost equal fitness. Using deterministic population models it has been shown that selection favors genotypes inside such networks, which results in increased mutational robustness. Here we demonstrate that this effect is massively enhanced by recombination. Our results are based on a detailed analysis of mesa-shaped fitness landscapes, where we derive precise expressions for the dependence of the robustness on the landscape parameters for recombining and non-recombining populations. In addition, we carry out numerical simulations on different types of random holey landscapes as well as on an empirical fitness landscape. We show that the mutational robustness of a genotype generally correlates with its recombination weight, a new measure that quantifies the likelihood for the genotype to arise from recombination. We argue that the favorable effect of recombination on mutational robustness is a highly universal feature that may have played an important role in the emergence and maintenance of mechanisms of genetic exchange.

15 figures, Supplementary appendix, supplementary figures

References in corpus (6)

• Mutation, selection, and ancestry in branching models: a variational approach
• Statistical theory of phenotype abundance distributions: a test through exact enumeration of genotype spaces
• The Effect of Recombination on the Neutral Evolution of Genetic Robustness
• Rare events in population genetics: Stochastic tunneling in a two-locus model with recombination
• Increased adaptability to rapid environmental change can more than make up for the two-fold cost of males
• Large components in random induced subgraphs of n-cubes

Cited by in corpus (2)

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