How did the lab mouse come to be?

The history of mouse genetics might have begun in the 1860s if Gregor Mendel had not been forbidden to breed mice within the monastery and, thus, carried out his classic genetic studies with sweet peas. Rather, French geneticist Lucien Cuénot was the first to demonstrate Mendelian inheritance in mammals using the inheritance of coat colors in mice (1902). In 1903 William Castle at the Bussey Institute at Harvard also published a paper on coat color genetics in mice. Castle’s student, Clarence Cook (“C.C.”) Little, is credited with conceiving of and creating the first inbred strain of laboratory mice (DBA, named for its coat color genes: dilute, brown, nonagouti) to unravel the genetics of cancer. Little also created the C57/C58 family of strains at the Bussey and later went on to found The Jackson Laboratory in 1929.

Mouse fanciers of the late 19th and early 20th centuries in Asia and, later, Europe and America were the origin of most laboratory mice of today. Because of their beginnings in the mouse fancy trade, laboratory mouse strains are a genetic mix of four different subspecies: Mus musculus musculus (eastern Europe), Mus musculus domesticus (western Europe), Mus musculus castaneus (Southeast Asia) and Mus musculus molossinus (Japan). Within common inbred strains, the largest contribution of each strain’s genome originates from Mus musculus domesticus.

Many inbred strains derive from the colonies of Miss Abbie Lathrop, a mouse fancier who bred and sold mice in Granby, Massachusetts, from ~1900 to her death in 1918. Not only was Lathrop an avid mouse breeder, she was a scientist, carrying out experiments in collaboration with scientists such as William Castle and C.C. Little. She was one of the first to discover a link between hormones and cancer susceptibility back in 1916. Lathrop’s breeding records and notebooks, including many published observations, are preserved in the library at The Jackson Laboratory.