This mutation is located in the Rho GTPase Activating Protein 36 (Arhgap36) gene and appears to occur in no other mammal, according to a research team led by Stanford University School of Medicine scientists. The sex-linked orange 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...