André Lwoff

Origins and early life

André Michel Lwoff was born on 8 May 1902 at Ainay-le-Château, in the Allier, into a Jewish family of Russian and Polish origin: his mother Marie Siminovitch was an artist, his father Solomon Lwoff a psychiatrist. He joined the Pasteur Institute in Paris at nineteen and stayed there for his entire career, finishing his doctorate in 1932 and continuing with a Rockefeller grant.

Work and career

His question was what a virus is doing when it appears to be doing nothing. A bacteriophage can enter a bacterium and vanish — the cell goes on dividing, generation after generation, apparently unharmed, and then one day the culture bursts and phage pours out. Lwoff showed that the virus had not left: it had folded itself into the bacterium's own genome and was being copied along with it, silent until something — ultraviolet light, for instance — released it.

Lysogeny, as this is called, gave biology its first sight of a virus living inside a host's heredity, and the model on which François Jacob and Jacques Monod built the regulation of genes. The three shared the Nobel Prize in Physiology or Medicine in 1965. He worked all his life with his wife, the microbiologist Marguerite Lwoff, and opposed capital punishment. He died on 30 September 1994.