The importance of non-additive effects for adaptation

Wider research context: Although epistasis and dominance are well-documented and common, their importance during rapid adaptive processes is not yet understood. Hypotheses: We will test the hypothesis that non-additive effects have no large effect on the trajectories of selected alleles, although the influence of non-additive effects on the phenotype of individuals is ubiquitous. Approach: The proposed project builds on the strength of experimental evolution using the obligate sexual model organism Drosophila melanogaster. Starting from two founder genotypes the genomic signature of adaptation to different stressors, which are either applied individually or combined, is used to measure non-additive effects (i.e. epistasis and dominance). Two complementary approaches are used to quantify the deviations from expectations based on purely additive effects: time resolved allele frequency changes and pairwise competition experiments of three different genotypes. The project will provide a robust empirical basis about the importance of epistasis and dominance for the selection response during adaptive processes. Hence, genome scans for selection signatures will benefit from the outcome of this study. Innovation: The proposal provides an entirely novel approach to study the impact of non- additive effects during adaptive processes. Primary researchers involved: Christian Schlötterer