THE BEHAVIORAL INDICATIONS THE MOUSE EXPRESSES IS A TYPICAL EXAMPLE OF A "KNOCK-OUT GENE" RESEARCH.
A knockout mouse, or knock-out mouse, is a genetically modified mouse (Mus musculus) in which researchers have inactivated, or "knocked out", an existing gene by replacing it or disrupting it with an artificial piece of DNA. They are important animal models for studying the role of genes which have been sequenced but whose functions have not been determined. By causing a specific gene to be inactive in the mouse, and observing any differences from normal behaviour or physiology, researchers can infer its probable function.
