DISSERTATION RESEARCH: Tracking Timing of Migration and Diversification Across North and South America in Agalinis (Orobanchaceae)

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The underlying evolutionary history, or phylogeny, of organisms from diverse biomes provide a framework for understanding where these lineages originated geographically, how they have subsequently diversified, and how these biomes were assembled in the past. This project explores evolutionary relationships in Agalinis (Orobanchaceae), a flowering plant genus of approximately 70 species with a New Word distribution and with South American centers of diversity in two recognized biodiversity hotspots: the Andes and the Cerrado of Brazil. Agalinis is an ideal clade for investigating historical biogeography and diversification between the two continents and between the Andes and Cerrado, as well as patterns of morphological evolution following a rapid radiation into South America. In addition to using standard phylogenetic and divergence time estimation approaches, this research will also employ a newly developed multi-species coalescent approach for estimation of the species tree and divergence times within the South American clade of Agalinis. Our goals are to: 1) assemble the first broadly-sampled phylogeny of Agalinis, 2) estimate the species tree and divergence times, using both standard phylogenetic and new coalescent methods for the South American clade, 3) investigate migration and diversification between North and South America and between the Andes and the Cerrado within South America, with efforts to correlate potential shifts in diversification with geological and paleoclimatic reconstructions, and 4) investigate morphological character evolution. The utility of this research extends beyond the systematics of Agalinis and will be a valuable contribution not only to studies of diversification and character evolution of lineages in South America, but also to comparative phylogenetic research in the Neotropics. This project relies extensively on established international collaborations, particularly in Brazil. The results of the research will be disseminated through peer-reviewed publications, presentations at national conferences, and through the my-plant.org web portal. Photos of plants in the field have already been deposited with the Parasitic Plant Collection, a website which provides information to researchers and the public. The co-PI is supervising an undergraduate student on a small project overlapping with the research outlined here, and will mentor a Brazilian undergraduate in a lab exchange from USP in 2013. Additionally, the co-PI will continue her involvement with the NSF-supported Planting Science online high school mentoring program, furthering the educational impact of the proposed research.