Organismal and Molecular Evolution in Plants
Christopher P. Randle, Assistant Professor

My primary research interest is in establishing the connection between organismal and molecular evolution in plants, focusing on the evolution of photosynthetic genes in non-photosynthetic, or holoparasitic, plants. Holoparasitic plants obtain all water and nutrients from host-plants. The evolution of holoparasitism results in a decrease in functional constraint on characteristics associated with autonomous nutrient acquisition. Therefore, holoparasites often lack leaves or roots, chlorophyll, or any of the photosynthetic apparatus. My research indicates that function of some photosynthesis-related genes is maintained by natural selection in holoparasitic lineages. One explanation is that these genes have been “borrowed” by non-photosynthetic pathways in holoparasites. As a systematist I am also concerned with the classification of organisms based on shared ancestry. I have used a combination of molecular and morphological data to reclassify the parasitic genus Harveya as well as other, non-parasitic taxa, including the genus Crassula (Crassulaceae) and tribe Coreopsidae (Asteraceae). I am also interested in the process by which evolutionary trees are inferred from DNA-sequence data, specifically “Bayesian” methods. These methods require that probabilities of competing hypotheses be stipulated a priori. The focus of my work has been on whether a probability distribution can be obtained that is non-informative regarding all composite hypotheses of relationship in the absence of prior knowledge of diversification patterns.

For more information on this REU opportunity, please e-mail Dr. Randle at cpr003@shsu.edu.