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JJacob, François ACOB, FRANÇOIS(1920- )
French molecular biologistFrançois Jacob made several major contributions to the field
of genetics through successful collaborations with other scien-
tists at the famous Pasteur Institute in France. His most noted
work involved the formulation of the Jacob-Monod operon
model, which helps explain how genes are regulated. Jacob
also studied messenger ribonucleic acid (mRNA), which
serves as an intermediary between the deoxyribonucleic acid
(DNA), which carries the genetic code, and the ribosomes,
where proteins are synthesized. He also demonstrated that
bacteriafollow the same general rules of natural selectionand
evolutionas higher organisms. In recognition of their work in
genetic control and viruses, Jacob and two other scientists at
the Pasteur Institute, Jacques Lucien Monodand André Lwoff,
shared the 1965 Nobel Prize for Physiology or Medicine.
Jacob was born in Nancy, France, to Simon Jacob, a
merchant, and the former Thérèse Franck. Jacob attended
school at the Lycée Carnot in Paris before beginning his col-
lege education. He began his studies toward a medical degree
at the University of Paris (Sorbonne), but was forced to cut his
education short when the German Army invaded France dur-
ing World War II in 1940. He escaped on one of the last boats
to England and joined the Free French forces in London, serv-
ing as an officer and fighting with the Allies in northern
Africa. During the war, Jacob was seriously wounded. His
injuries impaired his hands and put an abrupt end to his hopes
of becoming a surgeon. For his service to his country, he
received the Croix de Guerre and the Companion of the
Liberation, two of France’s highest military honors.
Despite this physical setback, Jacob continued his edu-
cation at the University of Paris. In his autobiography, The
Statue Within,Jacob said he got the idea for his thesis from his
place of work, the National PenicillinCenter, where a minor
antibiotic called tyrothricin was manufactured and commer-
cialized. For his thesis, Jacob manufactured and evaluated the
drug. Nearing thirty years old, he earned his M.D. degree in1947, the same year he married Lysiane “Lise” Bloch, a
pianist. They would eventually have four children.
With his professional future unsure, Jacob continued to
work for a while at the National Penicillin Center. The tide
turned when he and his wife had dinner with her cousins,
including Herbert Marcovich, a biologist working in a genet-
ics lab. Jacob recalled, “As Herbert spoke, I felt an excitement
rising like a storm. If a man of my generation could still go
into research without making himself ridiculous, then why not
I?” He decided to become a biologist the next day.
Jacob joined the Pasteur Institute in 1950 as an assistant
to André Lwoff. Lwoff’s laboratory location and its cramped
quarters earned it the name of “the attic.” The year 1950 was
an exciting one in Lwoff’s lab. Lwoff had been working with
lysogenic bacteria, which are destroyed (lysed) when attacked
by bacteria-infecting virus particles called bacteriophages.
The bacteriophages invade the bacterial cell, then multiply
within it, eventually bursting the cell and releasing new bacte-
riophages. According to Lwoff’s research, the bacteriophage
first exists in the bacterial cell in a non-infectious phase called
the prophage. He could stimulate the prophage to begin pro-
ducing infective virus by adding ultraviolet light. These new
findings helped to give Jacob the background he would need
for his future research.
Jacob continued his education at the University of Paris
during his first years at the Pasteur Institute, earning his bach-
elor of science in 1951 and studying toward his doctor of sci-
ence degree, which he received in 1954. For his doctoral
dissertation, Jacob reviewed the ability of certain radiations or
chemical compounds to inducethe prophage, and proposed
possible mechanisms of immunity.
Once on staff in the lab, Jacob soon formed what would
become a fruitful collaboration with Élie Wollman, also sta-
tioned in Lwoff’s laboratory. In the summer of 1954 he and
Wollman discovered what they termed erotic induction in the
bacteria Escherichia coli.They later changed the name of the
phenomenon to zygotic induction. In zygotic induction, the
chromosome of a male bacterial cell carrying a prophagewomi_J 5/6/03 3:28 PM Page 317