Free French hero won Nobel Prize for gene discovery

Francois Jacob, the geneticist, who has died aged 92, served with the Free French in the Second World War, when he was decorated for bravery, and in 1965 shared the Nobel Prize for Physiology or Medicine with Andre Lwoff and Jacques Monod for their discovery of how genes are regulated in bacteria and viruses.

Every cell of an organism contains all of its genetic blueprint — the genome — but until Jacob and Monod’s breakthrough, no one knew how cells selectively employ parts of the genome to endow themselves with specific capabilities. The concept they pioneered, known as “negative gene regulation,” is fundamental to cellular regulation for all organisms and is considered central to the subsequent development of molecular biology.

Francois Jacob was born in Nancy, eastern France, on June 17, 1920, the only child of middle-class Jewish parents. His father was a merchant, while his maternal grandfather had been the first Jewish four-star general in the French Army.

From the Lycée Carnot in Paris, Francois entered medical school at the Sorbonne, hoping to become a surgeon.

However, in 1940, he signed up to General de Gaulle’s Free French Army. Shipped to subSaharan Africa, for the next four years he served as a medical officer in General Leclerc’s 2nd Armoured Division.

Following the D-Day landings, in August 1944 he landed in Normandy, but a week later, Jacob was badly wounded when a German fragmentation bomb exploded beside him.

Although he was awarded the Cross of Liberation and the Legion d’honneur and Croix de Guerre, his dream of becoming a surgeon had to be abandoned because of his wounds. In 1950 Jacob managed to talk himself into a fellowship at the Pasteur Institute.

Jacob became laboratory director at the Pasteur Institute in 1956 and four years later was appointed head of its new department of cell genetics, where he remained until his retirement in 1991. When he, Lwoff and Monod won the Nobel Prize in 1965, it was the first time in 30 years that French scientists had won a Nobel in any of the sciences.

Jacob was professor of cellular genetics at the College of France from 1965 to 1992. He was elected a foreign member of the Royal Society in London in 1973. He later devoted his attention to genetic analysis of the mechanisms of cell division and the genetic properties of mammalian cells.