The increasing value of congenic mice in biomedical research.

The development of congenic mouse strains, strains which differ from their inbred partner strains by only a single selected character, was described; and three a examples of important finding made possible by the use of such strains were given. The first example showed how a gene in a major histocompatibility complex influences susceptibility to spontaneous leukemia. The second example illustrated how a particular constellation of genes in a congenic hybrid may lead to autoimmune disease that does not occur in either parental strain. The third example was concerned with function of major histocompatibility genes as identification markers which enable individual mice to recognize one an other by scent.