39 - Leptosiphon and Flower Color: Investigating Color Acquisition in Polemoniaceae using Phylogenetics
University of Florida
Molecular Systematics & Evolutionary Genetics
Transitions in flower color are asymmetric over evolutionary time, with some transitions more favorable than others. Several selective pressures and mechanisms involving pollinators often drive these color changes, while other forces such as genetic drift and pleiotropic effects may drive others. In this project, we investigated transitions in flower color in Leptosiphon (Polemoniaceae). Leptosiphon comprises 38 species and has a center of distribution in California. Based on our initial analyses, it appears that flower color (blue/purple, pink, and yellow) has been gained in many independent transitions from a white-flowered ancestor. A well-supported species-level phylogeny will allow for better mapping of floral characteristics. To refine phylogenetic relationships, plant material was obtained from field, herbaria, and greenhouse collections for 197 accessions, representing all 38 species, plus Phlox as an outgroup. We selected 96 samples, including all species and each color morph for a targeted gene capture protocol using MYbaits, a procedure that allows custom design of baits. Probe sequences were created through a reciprocal blast using four transcriptomes (two species of Phlox, Fouqueria macdouglaii, and Ternstroemia gymanthera) and the Arabidopsis genome. Probes for one hundred markers were created, those with large introns discarded before probe design. After gene capture, samples were multiplexed and sequenced with Illumina. Reads were assembled, and phylogenetic analyses were conducted on concatenated and individual gene data sets. The resolved phylogeny will be used to determine the number of transitions in flower color in Leptosiphon and the directions in which these changes have occurred.