An analysis of genetic factors regulating life-span in congeneic mice.

Controlled matings between two strains of mice that have minimum genetic heterogeneity but whose mean ages at death are significantly different were used to identify genetic factors that govern longevity. The congeneic pair, C57BL/10 (B10) and C57BL/10.F (B10.F), differ at a region of the genome in and around the H-2 complex and have mean ages at death of 706 +/- 14 and 456 +/- 15 days, respectively. B10.F also has a reduced level of basal serum IgA levels, a trait which segregates in F2 progeny. F2 and back-cross progeny were classified for the H-2 genotype and allowed to live out their life-span. Survival curves for F2 and backcross progeny selected on the basis of their H-2 type show that the progeny homozygous for the H-2 allele of B10.F have a mean age at death significantly different and reduced from that of the progeny homozygous for the H-2 allele of B10.