Effects of mutant steel alleles on leukemogenesis and life-span in the mouse.

Mutant alleles at the steel locus produce the pleiotropic effects of congenital anemia, sterility, and lack of hair pigmentation. Strain (WC/Re X C57BL/6)F1 Sl/Sld mice lived only half as long as heterozygotes and homozygous normal controls, differing only at the steel locus. Lymphocytic leukemia developed spontaneously in 37% of mice of the Sl/Sld genotype at an average age of 370 +/- 25 days and in 5% of heterozygotes and homozygous normal controls at 965 +/- 41 days. Severe ulcerative dermatitis occurred in 56% of Sl/Sld mice at an average age o4f 441 +/- 21 days and in 20% of heterozygotes and homozygous normal controls at 722 +/- 50 days. The mutant steel alleles provided an opportunity for study of the role of chronic anemia in life shortening and of a mechanism of gene action in spontaneous leukemogenesis.