Experimental evolution across different thermal regimes yields genetic divergence in recombination fraction but no divergence in temperature-associated plastic recombination

Phenotypic plasticity is pervasive in nature. One mechanism underlying the evolution and maintenance of such plasticity is environmental heterogeneity. Indeed, theory indicates that both spatial and temporal variation in the environment should favor the evolution of phenotypic plasticity under a variety of conditions. The frequency of recombination in the model system Drosophila melanogaster has long been known to exhibit phenotypic plasticity in response to temperature. Here were use a panel of replicated experimental evolution populations of D. melanogaster to test whether variable environments favor enhanced plasticity in recombination rate in response to temperature. In contrast to expectation, we find no evidence for enhanced plasticity in recombination in the variable environment lines. Our data confirm a role of temperature in mediating recombination fraction in D. melanogaster, and indicate that recombination is genetically and plastically depressed under lower temperatures. Our...