Joshua Lederberg, a pioneering geneticist and former president of Rockefeller University, died on Saturday of pneumonia, the university has announced. He was 82.

Mr. Lederberg shared the Nobel Prize in Physiology or Medicine in 1958 for demonstrating, while still in graduate school, that bacteria reproduce sexually. That discovery was key to the techniques underlying molecular biology and biotechnology.

Mr. Lederberg also served as president of Rockefeller, from 1978 to 1990, and advised nine presidential administrations. See an obituary in today’s New York Times for more details. —Lila Guterman