Organisms are comprised of interacting parts. Even within single cells, networks of proteins regulate basic functions. The impact of perturbing one part of an organism – for example, via genetic mutation – can often be modified by perturbation to other parts. This creates obstacles for scientists: how do we predict traits from genetic data when the same mutation can have different impacts? This also presents challenges during evolution: how does an organism adapt or evolve when changing one trait can influence many other traits, resulting in complex tradeoffs? To quantify the spectrum of effects that a specific perturbation may have on an organism, the Geiler-Samerotte lab measures how yeast cells respond to subtle genetic or environmental changes. Then, we study how cellular responses change when multiple perturbations are combined or when the magnitude of a perturbation is systematically varied. Our research provides insight about how interactions between small-effect genetic variants shape the evolution of complex traits.