François Jacob (1920-2013)
Born in Nancy in June 1920, François Jacob was the only son of Simon Jacob and Thérèse Franck, both from Jewish families with strong but surprisingly divergent convictions. Of his father, who combined religious practice with radical-socialist opinions, François Jacob wrote that he combined "a taste for tradition with a taste for revolution [1]".
His mother, an agnostic or even atheist, was politically much more conservative. François grew up with the affection and tenderness of this woman, who died in June 1940, "...in time," he wrote, "not to experience the horror, [...] the flight from the yellow star [2]". But "his ideal, his model", to use his own words, François Jacob found it in Dijon, with his maternal grandfather, Albert Franck, to whom he dedicated, he says, "a kind of adoration [3]". The first Jew to reach the rank of Lieutenant General, Albert Frank, "the General" as he calls him, made him understand that "heaven was empty" and that "there was an earth to fill [4]". As a child, he relied on him to build "a coherent representation of the world". From his time at the Lycée Carnot in Paris, he remembers a Republic school that was less concerned with teaching than with "subduing young people, standardizing them, casting them all in the same mold [5]". After passing his baccalauréat, attracted by surgery, he began studying medicine, but was soon interrupted by the war.
On June 17, 1940, his twentieth birthday, François Jacob was on the road to exodus with three of his comrades. It was there, on the way to southwest France, that he heard Pétain announce the armistice, which he had requested - in the words of his press release - "with honor and dignity... [6]". François Jacob immediately refused to submit. Determined to fight, he reached Saint-Jean-de-Luz and set sail the very next day for England with a friend. There, with a few thousand men, the Free French movement was formed, with the strategy of entering the war with the support of the African colonies. François Jacob asked to be assigned to the artillery. The health service was imposed on him. On September1, 1940, it was off to Dakar, then Brazzaville, Libreville and finally Fort-Archambault, where François Jacob was assigned to the Senegalese Tirailleurs regiment. From there, he was sent to Mao, a large isolated village north of Lake Chad, to work as a doctor, as punishment for refusing an assignment that would have kept him away from the fighting units. He was not allowed to join the troops heading for Libya until the summer of 1942. Fort-Lamy, then the desert crossing to Fezzan and Tripolitania - "a trek to the end of the world", for three thousand men, in "an impossible desert", he writes [7]. Finally, it's southern Tunisia. Days of uncertainty and nightmare in Ksar Rhilane, days decisive for the course of the war... First combat at Djebel Matleb, then at Djebel Garci, where he was wounded in May 1943. In April 1944, he left Casablanca for England. On August 1st, he landed on Utah Beach in Normandy. Eight days later, he was seriously wounded in an air attack. Evacuated to Cherbourg, then to the Val de Grâce hospital in Paris, François Jacob remained there for six months, and was later hospitalized again.
"Gloriously wounded", in his own words [8], he had another desert crossing ahead of him. The after-effects of his injuries put an end to his hopes of becoming a surgeon... What could he do? Finish his medical studies "as soon as possible", he writes [9]. A spell at the Cabanel center, set up by the army to produce antibiotics, and a medical thesis on one of them, tyrothricin, in 1947. The center closed and the years went by... François Jacob gradually developed an interest in biological research. He saw in it a "promise of future effervescence", "at the frontiers of genetics, bacteriology and chemistry [10]". He approached the few research centers that might be willing to take him on, but to no avail. As a last resort, he knocked on the door of the director of the Institut Pasteur, Professor Tréfouël, who welcomed him and offered him a research grant. All that remained was to find a laboratory willing to take him on. François Jacob's choice was made, and nothing would deter him: he wanted to join the laboratory headed by André Lwoff, where Jacques Monod was already working. André Lwoff's successive refusals did nothing to weaken his resolve. François Jacob insisted, and André Lwoff finally accepted him into his laboratory. Lwoff wrote of François Jacob's recruitment that his "preparation for research was [...] nothing less than classical", but that "energy, decisiveness, a spirit of sacrifice and enterprise, a refusal to accept defeat and tenacity in the struggle are among the essential qualities of a researcher [11] ". André Lwoff's sudden turnaround can be explained by the discovery he had just made. After years of effort, he has succeeded in inducing prophage in lysogenic bacteria. A new field of research is opening up, and... a new PhD student is very welcome! Scientific training at the Institut Pasteur and two science certificates later, François Jacob was finally up and running. The year was October 1950. Fifteen years later, he would open his Nobel lecture with these words: "I had the good fortune to arrive at the right place at the right time. In the right place, because there, in the attic of the Pasteur Institute, a new discipline was emerging in an atmosphere of enthusiasm, lucid criticism, non-conformism and friendship. It came at just the right time, because at the time, biology was in full effervescence, changing its ways of thinking, discovering new and simple material in micro-organisms, and moving closer to physics and chemistry. It was a rare moment when ignorance could become virtue André Lwoff embraced Darwinian and Mendelian theories, unlike many French biologists, who were more inclined towards heterodoxy. As for microbiology, it has yet to find its way into university lectures in Pasteur's homeland. François Jacob began with a rigorous and systematic study of lysogenic bacteria. On the one hand, he sets out to define the conditions for inducing the production of the viruses, bacteriophages, that they harbor in the form of proviruses, prophages, and, on the other, to understand the nature and properties of the latter, and the basis of the immunity that their presence confers on bacteria. In this way, he clarifies the phenomenon of lysogenesis, the capricious nature of which had even made us doubt its existence for a while. He transformed it into a subject of study with a much broader scope (the nature of the relationship between bacteria and their viruses), and attempted to generalize his conclusions to the viruses of complex organisms, both plants and animals. His unitary vision of living organisms, which was to guide all his thinking, was already evident in the monograph entitled Les bactéries lysogènes et la notion de provirus, a compilation of his thesis work, published in 1954. In the preface to this work, André Lwoff underlines his "exceptional research temperament"; "Within a fortnight, we knew we had recruited someone very good" says his colleague Georges Cohen. a "good friend", he adds, "he liked smooth relationships". Curious about the work carried out by the researchers around him, in particular Jacques Monod, he quickly established collaborations with several colleagues.
