Evolution of Plasticity in Response to Ethanol between Recently Separated Populations of D. melanogaster with Different Ecological Histories
While there is abundant theoretical work on the evolution of phenotype plasticity, empirical support has lagged. One model for the evolution of phenotype plasticity is by genetic accommodation. Under this model of evolution when a population encounters a new environment there are widely variable responses amongst different genotypes, which are then pruned by selection into a single adaptive response. Because of the requirement to replicate genotypes, testing this prediction requires inbred lines as well as populations that are both adapted and not adapted to a resource. We previously demonstrated that D. melanogaster adapted to ethanol through genetic accommodation using D. simulans as an ancestral proxy lineage. However, we wondered how generalizable these results were. Using a new population of D. melanogaster from France and an ancestral range population from Zambia we demonstrated here that the Zambian population is not adapted to ethanol and that the French population has evolved ethanol resistance through genetic accommodation. We also investigated alternative splicing in response to ethanol and find that gene expression and splicing appear to evolve independently of one another, and that the splicing response to ethanol is largely distinct between populations. Thus, we have independently replicated evidence for evolution by genetic accommodation in D. melanogaster, suggesting that the evolution of plasticity may be an important contributor to the ability to exploit novel resources.