Sex, Robustness, and Evolvability

Ricardo Azevedo (February 8, 2012)

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Abstract

Evolution is the movement of populations through a space of genotypes. This space can be modeled as an undirected network connecting genotypes that can be reached through mutation. In this view, the mutational robustness of a genotype is the proportion of its mutational neighbors that are viable. Robustness can facilitate the exploration of genotype networks, or evolvability. Sexual reproduction is also widely believed to promote evolvability, for two reasons. First, because it allows long jumps through genotype space. Second, because it selects for mutational robustness. Here, I show that, depending on the structure of the genotype network, sexual reproduction may not select for the highest mutational robustness, and can actually reduce evolvability.