The Nobel Prize in Physiology or Medicine 1965
Born: 8 May 1902, Ainay-le-Château, France
Died: 30 September 1994, Paris, France
Affiliation at the time of the award: Institut Pasteur, Paris, France
Prize motivation: "for their discoveries concerning genetic control of enzyme and virus synthesis."
Prize share: 1/3
Bacteriophages are viruses that attach themselves to bacteria, emptying their genetic material into them. At times, many new phage are created quickly, while at other times, new phage are formed only several bacterial generations later. In the early 1950s André Lwoff successfully explained how this process, known as lysogeny, works. The bacteriophage's genes are incorporated into the bacteria's genetic material, but remain latent until a trigger factor causes new phage to be formed. André Lwoff also showed that ultraviolet light can be one such factor.