The scientific legacy of Jacques Monod.

The operon model was the last "great" discovery of molecular biology, and a decisive event for the entrance of molecular biology into embryology. But the work of Monod was not limited to the elaboration of this model. He was one of the founders of molecular biology, in the paradigm of which biologists still work. I focus on two episodes of Monod's career--his strong opposition to Lysenkoism and the elaboration of the allosteric model--to outline the ideas and convictions of the early molecular biologists. Copyright 2010 Elsevier Masson SAS. All rights reserved.