X-linked allozymes of phosphoglycerate kinase as tools in experimental carcinogenesis in the mouse.

Experimental conditions are discussed that are necessary for a useful application of genetically marked laboratory animals to distinguish between clonal and nonclonal origin of induced tumors: quantitative discrimination of biochemical markers, definition of the "patch" sizes, evaluation of possible admixture of "contaminating" cells and the approach to congenicity of parental animal strains.