Escherichia coli and the Emergence of Molecular Biology

The creation of the "Phage group" by M. Delbrück, S. E. Luria, and A. D. Hershey in 1940 at Cold Spring Harbor played a crucial role in the development of molecular biology. In the 1940s, working with Escherichia coli and its viruses, Luria and Delbrück discovered the spontaneous nature of bacterial mutations and Hershey described recombination in bacteriophages and demonstrated with M. Chase that the genetic material that infects bacteria is DNA. At the same time, S. Benzer defined the structure of a functional genetic unit and J. Lederberg and E. Tatum discovered sexual recombination between bacteria. Some years later, Lederberg's group discovered extrachromosomal particles, the plasmids, and a novel way of genetic transfer through bacteriophages, called transduction. In 1949, at the Pasteur Institute in Paris, A. Lwoff uncovered the mechanism of lysogeny. Shortly afterwards, F. Jacob and E. Wollman unraveled the mechanism of the sexual process in E. coli and established the circularity of the bacterial chromosome. In the 1960s, J. Monod and F. Jacob, by genetic analysis of the E. coli lactose system, proposed the operon model for gene regulation and introduced the concept of messenger RNA. The elucidation of the double helix structure of DNA in 1953 by F. Crick and J. Watson had major consequences: the establishment of the copying mechanism (Meselson and Stahl), the discovery of the nature of the genetic code (S. Brenner) leading to its deciphering. E. coli and its phages were instrumental in the development of recombinant DNA technology based on the discovery of the restriction-modification system by W. Arber.