Molecular and genetic characterization of sex-linked orange coat color in the domestic cat.

The mutation in domestic cats causes variegated patches of reddish/yellow hair and is a defining signature of random X-inactivation in female tortoiseshell and calico cats. Unlike the situation for most coat color genes, there is no apparent homolog for in other mammals. We show that the is caused by a 5 kb deletion that leads to ectopic and melanocyte-specific expression of the ( ) gene.