Knockout mice are important animal models for studying the role of genes which have been sequenced but whose functions are not yet known. By causing a specific gene to be inactive in the mouse, and observing any differences from normal behaviour or condition, researchers can infer its probable function.
Mice are currently the most closely related laboratory animal species to humans for which the knockout technique can easily be applied. They are widely used in knockout experiments, especially those genetic questions which relate to human physiology.
Aspects of the technology for generating knockout mice, and the mice themselves have been patented in many countries by private companies.