The pioneering work in yeast genetics of Gerald R. Fink has played a significant role in advancing the broader field of molecular genetics. Leading the list of Fink’s groundbreaking contributions was his development of yeast transformation, a now commonly used technique that allows scientists to introduce genetic material (DNA) from another organism into living yeast cells so that the expression and hereditability of the introduced DNA can be studied. Today, not only is yeast used to study the genetic dissection of basic cellular processes in other organisms, including humans, but it is used as a kind of mini-factory to produce medically important products, including insulin and vaccines. Among Fink’s many other discoveries was the identification of the genetic mechanisms by which disease-causing fungi form probing filaments and switch from being benign to infectious. Uncovering the genetic mechanisms behind the formation of the filaments has led to a better understanding of how fungi can overpower the immune system—clues that may lead to new life-saving drugs.