Fertility studies of complementing genotypes at the albino locus of the mouse

Mice doubly heterozygous for two radiation-induced lethal alleles at the albino locus (C3H and C6H) show partial complementation: they are viable but runted and sterile. In C3H/C6H females oogenesis and mating are normal, but nearly all of their fetuses, even when genotypically normal (+/C3H or +/C6H), fail to survive beyond midgestation. Abnormalities of spermatogenesis, i.e. morphological defects in head condensation and a deficiency in numbers of maturing spermatids, are histologically detectable in the testes of C3H/C6H males. Spermatozoa from the vasa deferentia of such males are predominantly nonviable, immotile, and grossly abnormal in morphology.