André Michel Lwoff

André Michel Lwoff was born in France on 8 May 1902. He spent decades studying the microbial world, eventually focusing on bacteriophages — viruses that infect bacteria. His core discovery was lysogeny: the phenomenon where viral DNA integrates into a host cell's genome, sitting silent until triggered to replicate and destroy. The finding opened a new chapter in virology and genetics. In 1965, he received the Nobel Prize in Physiology or Medicine for that work. He continued research and teaching until his later years, dying on 30 September 1994.