Joshua Lederberg, molecular biology pioneer

Joshua Lederberg, a bacterial geneticist, died on Saturday. This guy had a huge influence on my field, discovering that bacteria can exchange genetic materials. Indeed, he and his ex-wife developed the now classical technique of "replica-plating" that allows screening of hundreds of thousands of bacterial isolates (believe me, I've done it!). From the New York Times obituary:

Donald Kennedy, the editor of Science magazine in Washington and a former colleague of Dr. Lederberg’s at Stanford, said that on Dr. Lederberg’s arrival at the school nearly a half century ago, “he was already a hero, the most important founder of bacterial genetics and microbiology.”

He was 82.