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Chapter 12 : The Switch
The epoch, that of molecular biology, may in its turn be seen as a composition of various “scenes,” as those which are threaded along a play by Bertolt Brecht, where a multitude of protagonists move about and spread their energy with passion. Jacques Monod has been, and will be remembered as, one of those very great men around whom the main events of contemporary biology have synthesized and harmoniously gathered, as the large tableaux around Brecht’s hero. According to the author, the history of RNA is that of a mysterious substance which did not interest anybody except a few cytologists. The finding that plant viruses contain, apart from proteins, ribonucleic acid has not only led one to perceive the functional universality of the RNA in biological systems, but has also helped in the analysis of its physicochemical composition. Jacob, Meselson, and Brenner brilliantly demonstrated that Volkin and Astrachan's RNA operated on preexisting ribosomes as a template biopolymer, organizing as a real "viral messenger" the proteins newly synthesized by the phage. The birth, at times difficult, of messenger RNA was received with great acclaim. The finding of a strict complementarity in the sequences of the messenger RNA and the homospecific DNA (Spiegelman) was also a major contribution.