Dr. Jonathan Fitz Gerald, assistant professor of biology at Rhodes, has been awarded a $400,000 three-year National Science Foundation (NSF) grant (effective June 15, 2013) for his research using the flowering plant Arabidopsis thaliana as a model to understand the different roles played by maternal and paternal genes.
This grant includes funds for 12 summer research opportunities for Rhodes students and nine fellowships during the fall/spring semesters. Currently, Ellen Dahl ’14 and Phuong Le ’15 are working on these projects and recently presented their research at the Society for Developmental Biologist’s southeastern regional meeting.
Fitz Gerald’s work is titled “RUI-Identification of Genes and Cellular Processes Targeted by Imprinted Pathways in Natural Variants of Arabidopsis thaliana.” According to Fitz Gerald, “Most of us are aware that we carry two copies of our genes, one copy from our mothers and one from our fathers. What most people don’t realize is these genes can have completely different properties depending on which parent provides them. In particular, I study a gene where only the maternal copy gets turned on. The paternal copy just sits there doing nothing even if it is genetically identical to the maternal copy.”
The project will first employ mathematical modeling to identify the inheritance patterns of these parentally "imprinted" or "silenced" genes. These models then will be used to isolate the genes responsible for parental controls. Finally, the project aims to link these genes to specific events in early development using 3D time-lapse video microscopy.
This type of gene regulation is called “Parental Genomic Imprinting” and has only been characterized in seed plants, like Arabidopsis, and placental mammals. When asked about this unlikely pairing, Fitz Gerald replied “if you try to imagine what trait we have in common with, say, a banana that we don’t share with other animals, like chicken or fish, it is essentially that mammals and seed plants maintain a nutrient bridge to our offspring after fertilization. The placenta in mammals and the seed endosperm in plants provide a conduit of resources that is under the regulation of both maternal and paternal genes. The parental conflict hypothesis states that the father will ‘take advantage’ of this structure to get more resources for his offspring whereas the mother will balance resources. In fact, many of the parentally imprinted genes were first characterized based on their effect on offspring size.”
The work on this project will be directly translatable to agriculture, particularly in biofuel production, as seed size is associated with plant vigor. Potentially, this work could lead to the capacity to modulate seed sizes independent of normal genetic mechanisms. Because plants are the only model outside of mammals where this phenomenon exists, Fitz Gerald says these studies also might shed new light on human imprinting and be important in understanding childhood disorders, such as Prader-Willi Syndrome and Angelman’s Syndrome, which stem from mutation in imprinted genes.