Escherichia coli is widely used as a standard laboratory model for studying bacterial gene regulation.
E. coli became a foundational organism in molecular biology because it grows quickly, is relatively easy to culture, and has well-characterized genetics. Researchers used it to uncover important principles of gene control, including the operon model. In 1961, François Jacob and Jacques Monod described the lac operon, which regulates genes needed to use lactose as an energy source.
E. coli also became central to recombinant-DNA technology. Scientists can insert genes into laboratory strains so they produce proteins such as human insulin. Most E. coli strains are harmless and live in the intestines of humans and other animals, although some strains cause diarrheal disease or urinary infections.
Laboratory E. coli should not be treated as representative of every E. coli strain. Their safety and behavior differ substantially from pathogenic variants such as enterohemorrhagic E. coli.