The Birth of the Operon

Abstract

What is the operon, whose 50th anniversary is being celebrated this week? The word heralded the discovery of how genes are turned on and off, and it launched the now-immense field of gene regulation. The idea was born in André Lwoff's laboratory at the Institut Pasteur. At one end of a long corridor in the loft of a building devoted to research on bacteria were Lwoff, Elie Wollman, and myself. At the other end were Jacques Monod and his group. Lwoff studied lysogenic Eschericia coli bacteria capable of producing bacteriophage without infection. Monod was analyzing the properties of the β-galactosidase enzyme in the same bacterium: an enzyme required for the metabolism of lactose that was produced only when the culture medium contained galactosides. To all and sundry the two systems appeared mechanistically miles apart. But their juxtaposition would produce a critical breakthrough for our understanding of life, demonstrating that we cannot presume to know how new ideas will arise and where scientific research will lead.