A prime example of X inactivation is in the coat-color patterning of tortoiseshell or calico cats (Figure 1). In cats, the fur pigmentation gene is X-linked, and depending on which copy of the X ...

Tortoiseshell cats have a brindling pattern (mixture) of orange and non-orange hairs throughout the coat, with some areas mostly orange or non-orange. Calico cats have distinct patches of orange ...