François Jacob's lab in the seventies: the T-complex and the mouse developmental genetic program.

The existence of a genetic program of development was proposed by molecular biologists in the nineteen-sixties. Historians and philosophers of science have since thoroughly criticized this notion. To fully appreciate its significance, it is interesting to consider the research which was pursued during this period by molecular biologists who proposed this notion. This study focuses on François Jacob's work and on the model of development supported by his lab in the early seventies, the T-complex model. This episode of Jacob's scientific activity has since been forgotten. Characterization of this model shows that the notion of program was used in a metaphoric way and that it did not put any constraint on the work pursued in the lab at that time. Some attention is devoted to the origin of this metaphor in the context of the nineteen-seventies.