Mice homozygous for the smaller size mutation are 25-50% smaller in body size than wild-type siblings. Only approximately 5% homozygotes are produced from either heterozygote x heterozygote or heterozygote x homozygote crosses, far fewer than predicted by Mendelian inheritance, indicative of either incomplete penetrance or premature death before the phenotype is evident. This strain also has a high rate of cataracts in mice assessed at 18 weeks of age.
The smsz mutation arose spontaneously in the CByJ.Cg-hml/GrsrJ strain at The Jackson Laboratory. The hml phenotype was selected away in sibling intercrossing the smsz mutant subline, although there is a small possibility that this recessive mutation may still be segregating in the genome. Sperm was cryopreserved from homozygous males at generation F16.
When using the CByJ.Cg-smsz/GrsrJ mouse strain in a publication, please cite the originating article(s) and include JAX stock #018550 in your Materials and Methods section.