The overarching goal of this recently funded research project is to understand how the structure of genetic and developmental pathways shapes the trajectory of phenotypic evolution on a phylogenetic scale. Focusing on the colorful Petunieae clade, we will trace the evolution of floral pigmentation and the expression of the underlying pigment pathway across the phylogeny to test the role of regulatory variation in color diversification. First, we plan to infer the history of flower color shifts in the tribe using a new phylogeny constructed from transcriptomic data. Building on this phylogenetic framework, we will use comparative methods and biochemical profiling to quantify the evolutionary relationship between changes in the expression of pathway genes and pigment variation. Given the modular nature of the regulation of these genes, we will also test for correlated evolution of gene expression across the phylogeny. As part of the NSF-CAREER program, this interdisciplinary project will be integrated with a large suite of educational initiatives.  We will be designing inquiry-based course modules for undergraduates and high school students as well as outreach activities to share with the local community.

We will be carrying out the field collections for this project in collaboration with Dr. Loreta Brandão de Freitas from the Universidade Federal do Rio Grande do Sul in Brazil and Dr. Gloria Barboza from the Universidad Nacional de Córdoba in Argentina.

Supported by NSF-DEB 1553114

Relevant publications:

Ng, J.+, L. B. Freitas & S. D. Smith. Stepwise evolution of floral pigmentation predicted by biochemical pathway structure. Evolution 72: 2792-2802. LinkReprint Request

Ng, J.+ & S. D. Smith. 2018. Why are red flowers so rare? Testing the macroevolutionary causes of tippiness. Journal of Evolutionary Biology 31: 1863-1875. LinkReprint Request

Image by Vo Rogačevski dvor 15 maj 2012 (106)