Piebaldism [is] the result of a mutation in the KIT gene, which causes an unusual distribution of melanocytes—the cells that give eyes, skin, and hair or fur pigment.

When a cat is still an embryo, all of its available melanocytes are bunched up toward its back, where its spinal column will eventually form. As the fetus develops into a mewling kitten, pigment cells spread throughout the developing body. If the melanocytes are evenly distributed, the cat could have a unicolor coat, like Sabrina the Teenage Witch's all-black cat, Salem, or the all-white Hello Kitty. But in many animals, the cells spread irregularly. That's how you get a cat like Sylvester, who's black from his back to his legs, but white down to his toes.

Our team of researchers from the universities of Bath, Edinburgh and Oxford have been working to unlock the mystery of how these animals get their distinctive patterns. We have discovered that the way these striking pigment patterns form is far more random than originally thought. Our findings have implications for the study of a wide range of serious embryonic disorders in humans, including diseases affecting hearing, vision, digestion and the heart.[...]

Although the effects of piebaldism are relatively mild, it is one of a range of more serious defects called neurocristopathies. These result from defects in the development of tissues and can manifest as heart problems, deafness, digestive problems and even cancer. The diseases are all linked by their reliance on a family of embryonic cells called neural crest cells. By understanding piebaldism better, we can improve our understanding of these related and more serious diseases.

The distinctive patterns were known to be caused by a mutated gene, but how the faulty DNA produced the signature white bellies and other splashes of light on animals’ coats was far from clear.

The discovery has led researchers to a mathematical model that describes how the curious patterns arise through the movement and growth of pigment cells when the animals are still growing in the womb.

The formula could help scientists understand not just the variations of animal colourings but also more serious, related conditions called neurocristopathies that cause deafness, gut disorders, heart defects and cancer in humans when cells fail to move to the right positions.