Leland H. "Lee" Hartwell was a pioneer in the mid-1960s in developing yeast as a model system for genetics. He then used that system to help decipher the cell cycle and to discover in the 1980s an important pathway in cancer development. Through his hypothesis on checkpoints, he proposed a genetic link between disruptions the normal cell cycle and cancer cell proliferation.

Born in Los Angeles, California, Hartwell first began to explore his interests in science, and particularly physics and math, with the help of his high school teachers. After a year at Glendale Junior College, he transferred to the California Institute of Technology (CalTech) as an undergraduate student and spent much of his time conducting research on phages in various scientists' labs. One of the most noted of the scientists was Bob Edgar, who was part of the Max Delbrück group. Delbrück...