The laboratory mouse. Its diploid chromosome number is 20, and extensive genetic maps are available for the 19 autosomes and the X chromosome. There are large collections of strains containing neurological mutants, loci associated with oncogenic viruses (especially retroviruses), loci that encode enzymes, and histocompatibility loci. The total number of mapped genes is about 7,000. The mice housed in laboratories throughout the world are all derived from three subspecies. These are all offshoots of an original population that began migrating from northern India about 900,000 years ago. The mouse genome contains 2.5 gbp of DNA and about 30,000 structural genes. Roughly 80% of these have identifiable orthologs in the human genome. See Classification, Chordata, Mammalia, Rodentia; Chronology, 1905, Cuénot; 1909, 1914, Little; 1936, Bittner; 1940, Earle; 1942, Snell; 1948, Gorer et al.; 1953, Snell; 1967, Mintz; 1972, Benacerraf and McDevitt; 1975, Mintz and Illmensee; 1976, Hozumi and Tonegawa; 1980, Gordon et al.; 1987, Kuehn et al.; 1988, Mansour, Thomas and Capecchi; 1994, Zhang et al., Arendt and Nübler-Jung;, Mouse Databases; Hox genes, mouse inbred lines, oncomouse, T complex.
Subjects: Genetics and Genomics.