Mice & genetics

Mice have been used to study mammalian specific genes to be altered. For many years humans have altered the genetics of animals through selectively breeding for particular traits.

The first mouse genetics studies

Mice were first used for genetics research by the French biologist Lucien Cuénot in 1902. His breeding experiments showed that three mnemons (genes), allowed production of one chromogen (pigment) and two distases (enzymes). The combination of the chromogen and one of the enzymes produced either a black or yellow colour. If there was no chromogen the mouse was albino. He showed mice inherited these coat colours in ratios predicted by Mendel’s inheritance laws.ANCHOR Mendelian genetics had only been applied to plants previously, and the news that the same rules held true for animals was groundbreaking for the field of genetics. A few years later Cuénot discovered the first lethal genetic mutation in the mouse.ANCHOR

Inbred strains

In the United States, William Castle and Clarence Little began to breed mice, and produced a series of studies on the genetics of mouse coat-colours.ANCHOR Little worked with a mouse-breeder and realized that they could breed for particular characteristics, which were useful for modeling different diseases. He developed the first ‘lab mouse’ inbred laboratory strains. It was soon realized that to notice the changes when the genetics of mice are altered, all the mice of a particular strain must be as similar as possible. This gave a uniform background to compare with new variations. Having strains of mice with very similar genetics has advantages for all biological sciences for the same reason – it is easier to identify a change. Today, there are several hundred strains of inbred mice, and many of Little’s original inbred strains are still in use.

The first inbred mouse strain created by Little was the DBA (dilute brown non-agouti) mouse in 1909. In 1921 he bred the C57BL/6 strain, which became the first mammal to have genome sequenced, many years later in 2002.ANCHOR Clarence Little went on to found the Jackson Laboratory in the USA, a world-famous centre for mouse genetics.

Later developments

Most laboratory mice are hybrids of different sub-species, most commonly Mus musculus domesticus and Mus musculus musculus, and many, although not all are from inbred strains. The long history of breeding, together with their short life-spans and breeding cycles has made mice particularly useful for studying mammalian genetics.

The history of using mice as a model for genetics ensured that many mutations and genes were identified during the 20th century, and the first mouse gene was isolated in 1977.ANCHOR Genetic technology advanced rapidly during the 1980’s leading to the development of transgenic and knockout mice.

• Year: 1902
• Scientist(s): Lucien Cuénot, William Castle, CC Little
• Animal(s): Mouse
• Countries: France, United Kingdom, United States of America
• Research field(s): Evolution and environment, Genetics, Medical technologies
• Medical application(s): Basic research

Last edited: 3 November 2014 12:08