Tyler Shimko, University of Utah
Differences in the genomes of organisms control an organism’s ability to deal with and adapt to environmental stresses. In this project, two strain isolates of the nematode Caenorhabditis elegans were analyzed using high-throughput assays measuring growth and offspring production to determine the genes that confer a greater resistance to the herbicide paraquat. Paraquat acts by interfering with electron transport mechanisms within the cells of living organisms. This mechanism not only allows it to act as an effective herbicide, but also causes it to pose a considerable risk to the health of animals, including livestock and humans. Using statistical genetics, regions of the genome were identified that are likely responsible for differences in growth rate and fecundity observed in the two strain isolates when grown in paraquat. Near-isogenic lines and extra-chromosomal arrays were then created to isolate these portions of the genome in a control genetic background. This approach allowed us to be able to attribute any differences in the two traits to the genes contained within the intervals. After analyzing the body size data, representing the growth of the animals over 72 hours, we were able to draw a preliminary conclusion that an interval on chromosome V may have a small but significant effect on growth determination. As a result of this project, a specific interval was identified that may be responsible for a greater growth rate, three near-isogenic lines were created, and 34 extra-chromosomal arrays were generated. This work will be used in the future to identify the gene(s) responsible for the greater growth rate and fecundity observed in some animals exposed to the herbicide paraquat. These results will allow us to draw conclusions about the roles that these genes, and others like them, play in an organism’s ability to cope with environmental stresses.