Year of Publication


Degree Name

Master of Science (MS)

Document Type

Master's Thesis


Agriculture, Food and Environment



First Advisor

Dr. Xuguo Zhou


Assessing the risk of transgenic crop products is essential when determining the safety of a crop for deregulation and commercialization. The Organization of Economic and Cooperative Development (OECD), International Standards Organization (ISO), and governmental regulatory agencies require a battery of tests to demonstrate the safety of a GM product against several surrogate species of organisms that perform various ecosystem services. Assays are performed using toxicology methods established for pesticides. These methods have been applied to testing the safety, specificity and fate of Bacillus thuringiensis (Bt) Cry protein toxins engineered into crop plants and information exists on the effects on non-target organisms (NTOs). Toxicology assays are typically evaluated through a tier-based approach, where, if no or negligible risk via oral toxicity or phenotypic changes then a risk decision can be made. Long term exposure studies are often performed after commercial release of the crop occurs and provide a more in depth understanding of environmental impacts. Risk analyses are currently being performed on the product of the next generation of GM crops that express dsRNAs against Western Corn Rootworm. This thesis provides another such study, primarily focused on Folsomia candida, a microarthropod that is the subject of numerous toxicological studies. I describe the development of dsRNA stability assays, which indicate stability of dsRNA across assay time, both with and without F. candida. When exposed to dsRNA levels several orders of magnitude higher that what would be encountered in the environment, F. candida is not negatively impacted as seen through gene expression and life history trait analysis.

Digital Object Identifier (DOI)