The first model for the control of protein production was the lac operon. This system of feedback and negative regulation is used by bacteria, however, the general principles also apply to higher organisms. Another method of protein regulation involves the unwrapping of DNA.
Francois Jacob and Jacques Monod figured out how bacteria controlled the production of an enzyme called beta-galactosidase. This system of feedback and negative regulation became the lac operon and was the first model for the control of protein productio
François Jacob talks about bacterial mutants that could not metabolize lactose. Using these mutants, Jacob and Monod figured out how protein production is controlled.