Abstract

Many historical studies have been devoted to the French school of molecular biology, in particular to the work of Jacques Monod on adaptive enzymes. By focusing on Francois Jacob's studies on lysogeny between 1950 and 1960, we intend to redress the imbalance of historiography, as well as proposing a more fruitful point of view for understanding the relative importance of international contacts and local traditions in the genesis of the operon model.Elie Wollman and Jacob's work on temperate bacteriophages rendered respectable a system that had been considered an artefact for more than two decades. They did this firstly by modelling their studies on those of the US phage group and secondly by basing these studies on a complex vision of the relations between bacteria and bacteriophages. The interaction between bacteria and temperate bacteriophages was considered ab initio as a biochemical process, the mechanisms of which would eventually be characterized. It was also considered as a ''normal'' phenomenon that could be used as a model to understand the process of differentiation, as well as the role of viruses in diseases and cancer. The temperate bacteriophage was a model system that was far more epistemologically open and, for this reason, in a sense more productive than the virulent phage studied by the US phage group.