SCIENTIFIC RESEARCH
I’ve published peer-reviewed scientific research in two major fields of study: evolutionary biology and behavioral genetics. As an undergraduate and as a lab manager, I studied the genetic basis for Post-Traumatic Stress Disorder at the Ann Arbor Veteran’s Hospital. As a Ph.D. student, I made a somewhat bizarre transition (ask me about it!) to studying plant evolution, and particularly the evolution of a plant-microbe symbiosis called “nodulation.”
EVOLUTIONARY HISTORY OF NODULATION GENES
My dissertation research was about the evolution of nodulation, a symbiotic partnership that some plants make with bacteria at their roots that’s important for human nutrition and agriculture. The plants feed sugar to bacteria housed in root “nodule” organs in exchange for nitrogen, an important nutrient used to make protein. Nodulation is the reason why legumes like lentils or beans have so much protein, which is why vegetarians and vegans tend to eat these foods. It’s also important in replenishing nitrogen in soils; that’s why corn is usually rotated with soy in farm fields.
Only legumes and a few related plant families can nodulate, which raises the question of why these lineages evolved this ability while other plants did not. My research focused on the evolutionary history of genes involved in the nodulation signaling pathway. I used a transcriptomics approach (looking at expressed genes) to identify nodulation-related genes in a nodulating non-legume called Elaeagnus umbellata, or autumn olive. I compared the gene sequence of these genes with those in other related species that do or do not nodulate, to identify patterns of gene duplication and loss involved the evolution of nodulation.
EVOLUTION OF LIFE CYCLE IN LAND PLANTS
All sexually reproducing eukaryotes (organisms with a nucleus in their cells) have a “life cycle” that alternates between a haploid phase (one set of chromosomes) and a diploid phase (two set of chromosomes). Humans are “diploid dominant” - we have two sets of chromosomes in our cells (one set from your mother and one from your father), and our haploid phase is reduced to sperm or eggs. In other organisms, like mosses, the haploid phase is the dominant, free-living phase, with the diploid phase being nutritionally dependent on the haploid body. Land plants show a striking pattern of reduction of the haploid phase, and expansion of the diploid phase, over the course of evolutionary history. We undertook a thorough synthesis of morphological, developmental and phylogenetic aspects of this evolutionary trajectory.
GENETIC VULNERABILITY FOR POST-TRAUMATIC STRESS DISORDER
Post-Traumatic Stress Disorder (PTSD) develops after trauma, but not all who are traumatized end up developing PTSD. Many factors influence susceptibility to PTSD, including genetics. My research as an undergraduate and later as a lab manager at the Ann Arbor Veteran’s Hospital, focused on how genetic and environmental risk factors interact to increase vulnerability.