During the fox ranch in Wisconsin a mutation arose, which gave rise to a platinum coat color. It has proved popular with the buyers of fox coats. But the breeders could not develop pure-breeding strain. Each time two platinums were crossed, the progeny obtained is 82 platinum and 38 normal progeny.
Platinum must be heterozygous in nature and should be in normal color (A/a). A number of 82:32 should be approximately close to the ratio 2:1. This shows that it is a part of the heterozygous ration (1:2:1) in which one genotype is non-available (A/A – homozygous platinum).
Thus, shows that the platinum allele is lethal allele, when in homozygous stage and in heterozygous state provides the coat color.