Escherichia coli

E. coli is the most well-understood bacterium in the world, and is an extremely important model organism in many fields of research, particularly molecular biology, genetics, and biochemistry. It is easy to grow under laboratory conditions, and research strains are very safe to work with. As with many bacteria, E. coli grows quickly, which allows many generations to be studied in a short time. In fact, under ideal conditions, E. coli cells can double in number after only 20 minutes.

Furthermore, a very large number of E. coli bacteria can be grown in a small space—many millions in a drop of broth, for example. These are important characteristics in genetic experiments, which often involve selecting a single bacterial cell from among millions of candidates, then allowing it to reproduce into high numbers again to perform additional experiments.

Many vital techniques, such as molecular cloning and overexpression of cloned genes, were initially developed in E. coli and are still simpler and more effective in the bacterium. Crucial experiments that illuminated the details of fundamental biological processes such as DNA replication, transcription, and translation were performed for the first time or with greatest success in E. coli. The bacterium is still a primary resource in many modern laboratories. Even research efforts that focus on other organisms, including humans or crop plants, often use E. coli extensively as a tool to facilitate cloning and DNA sequencing.