What maintains complex trait variation? Information on biochemical mechanisms can help us understand the link between genotype and phenotype, and the evolutionary factors that maintain genetic variation in populations or among species. Towards this goal, we are studying genetic variation in the enzymes of the glucosinolate pathway of Boechera and related genera to understand the evolutionary consequences of mutations causing changes in physiology, phenotype and fitness.

We are also interested in the forces that govern the evolution of biochemical pathways. We recently uncovered signatures of positive selection in two residues (pink residues in the figure) in the first enzyme in the glucosinolate pathway. Mutations at these sites cause a change in function of the enzyme that, in part, contribute to novel function in this pathway.