My project at the KLI will build on and expand my previous work on the environmental response capacities of organisms by addressing a central conceptual problem: resolving the role of genetic variation in adaptive evolution from an eco-evo-devo perspective. Although evolutionary biologists increasingly accept this updated perspective with regard to phenotypic variation, the field adheres to a gene-based model of evolutionary change. This explanatory disconnection has led to a scientific impasse, reflected in a current divide between researchers who emphasize eco-evo-devo approaches and those who view these ideas as inadmissable departures from the accepted evolutionary framework. To move forward and fully integrate development into evolutionary theory requires resolving this conceptual incongruity. Clarifying the relation of gene variants to complex phenotypes has broad resonance beyond evolutionary biology as well, from ideas about human diversity to funding priorities for medical research.