Figure 1. Effects of Rara gene dosage on eye weight

Both fixed eyes from each animal were weighed and averaged. The differences in weight among the three genotypes are expressed as residual values in milligrams after correction for differences in sex, body weight, and the logarithm of age. Note the dominance of the wildtype allele: mice with either one or two wildtype alleles (heterozygotes HT, or wildtype WT mice) do not differ significantly from each other in eye weight (see text). In contrast, the knockout mice (KO) have significantly smaller eyes (about 0.6 mg less). While this effect is modest it is nonetheless significant and has a p of 0.01 (dominant model, two tailed).