The mechanisms of action of most antifungal drugs are well known. However, we still do not know many of the resistance mechanisms. Still to be discovered are the set of potential resistance mutations, the conditions that affect their likelihood of occurrence, and the fitness benefits and tradeoff they incur. I will present our most recent attempts to fill these knowledge gaps using budding yeast as a model and one of the oldest antifungals, flucytosine. We performed experiments at two leve...