François Jacob, or the thirst for novelty

François Jacob tackled embryonic development from 1972 onwards, in the "Génétique cellulaire" Unit of the Molecular Biology Department at the Pasteur Institute, taking as models teratocarcinoma and the early stages of mouse embryo development. Studies on teratocarcinoma provided no major information about developmental processes, but they were the essential step without which embryonic stem cells (ES, iPS) would probably not have been discovered. The mechanisms of development were revealed by genetic approaches coupled to molecular biology, but with the Drosophila model rather than the mouse embryo. Since these studies, it has been revealed that developmental mechanisms among animals have proven to be universal. None of these results were predicted in 1972.