Architecture and Evolutionary Stability of Yeast Signaling Pathways

I have researched the effect that selection for the function of the High Osmolarity Glycerol (HOG) pathway has on the evolutionary stability of the pheromone response pathway in the yeast Saccharomyces cerevisiae. I first set out to demonstrate that, because the pheromone and HOG response pathways share protein components, selection for HOG function will enrich a population for cells capable of pheromone response. I performed experiments in both continuous and batch culture to demonstrate this effect. I then characterized the decay of the pheromone response pathway first, by measuring its mutation rate and second, by measuring the fitness of a series of strains with pheromone response gene deletions. I conclude with thoughts on possible experiments that may be used to further this research.