Phenotypic plasticity promotes recombination and gene clustering in periodic environments

The impact of changing environments on the evolution of genetic recombination is still unclear. While the Red Queen hypothesis provides a reasonable explanation for recombination, it requires coevolution with antagonistic species, such as host-parasite systems. We present a novel scenario for the evolution of recombination in changing environments: the genomic storage effect due to phenotypic plasticity. Using an analytic approximation and Monte Carlo simulations, we demonstrate that recombination evolves between a target locus that determines fitness, and a modifier locus that modulates the effects of alleles at the target. Evolution of recombination by this plasticity effect does not require antagonistic inter-specific interactions and, unlike in previous models, it occurs when only one target locus codes for a trait under selection. Furthermore, if the effects of multiple target loci are modified by the same plasticity locus, then the recombination rate among the target loci will tend to decrease, clustering the loci that influence a trait. These results provide a novel scenario for the evolution of recombination, highlighting the importance of phenotypic plasticity for recombination modification.