The mouse is the best genetic model organism for human biology. Among the animals used in research, teaching and testing, mice comprise the majority of all experimental mammals. The animal is easy to house and to use. Moreover, mice produce family lines that express genetic traits or conditions that can mimic the human condition, both physiologically and genetically. This genetic similarity, combined with the great convenience of use, accounts for their popularity. Genetically defined mouse lines have proved crucial because they have allowed researchers all over the world to perform experiments on the same genetic material. This has allowed results to be directly compared.

Mice were first used in cancer research in 1894. Initially, mice were used for same-species tumor transplantations and drug treatment studies. The genetic utility of mice in human disease processes was first recognized early in the twentieth century, when William Ernest...