Mechanisms of convergent flower color evolution above and below the species level

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This project will investigate whether evolution may be predictable at the genetic level. Phenotypic convergence, the appearance of similar forms in independent lineages, provides an opportunity for testing the predictability of genetic evolution. Similar phenotypes in different lineages are often due to similar changes at the genetic level. One possible explanation is that, among the possible mechanisms for producing a particular phenotype, some genetic changes are preferentially fixed during the course of evolution. This project will test the preferential fixation hypothesis by comparing the genetic basis of white flower coloration above and below the species level. The central hypothesis predicts that a wide array of mutations will be responsible for white-flowered mutants within pigmented species, but only a subset of these classes of mutations will be fixed during transitions from pigmented to white flowers at the species level. Using a group of species in the potato family, the PI will apply a combination of genetic, developmental, and biochemical approaches to test this prediction. The results will lead to a better understanding of the relationship between microevolutionary and macroevolutionary change. These studies will have important implications for manipulating and enhancing pigment content in horticultural varieties and crops. Plant pigments, including those targeted by this project, are strong antioxidants that contribute to the positive health benefits of a diet rich in fruits and vegetables. Thus, a better understanding of how genetic changes affect pigment biosynthesis adds to the potential for improving crop species. The project encompasses local outreach activities for K-12 students in order to promote interest in plant evolutionary biology and to spread awareness about the importance of plant pigments in human health.