The story of how the cat got its coat

Ever wonder how some cats get their distinctively black and white tuxedo-style coats? New research is showing the answer may also help scientists understand some human medical conditions and debilitating diseases.

Cats with skin and fur marked by white patches in this way are known as “bicolor" or “piebald,” a recent article explains. Piebaldism is seen not only in cats and is also common in dogs, cows, pigs, deer and horses. I also appears rarely on human skin and is caused by a mutation in a gene called “KIT.”

Piebaldism usually manifests as white areas of fur, hair or skin due to the absence of pigment-producing cells in those regions. These areas usually arise on the front of an animal, commonly on the belly and the forehead.

The article states that although the effects of piebaldism are relatively mild, it is one of a range of more serious defects called neurocristopathies and can manifest as heart problems, deafness, digestive problems and even cancer. These diseases are all linked by their reliance on a family of embryonic cells called neural crest cells.

Animals acquire piebald pigmentation patterns on their skin when they are still developing embryos. Piebaldism arises when the precursors of pigment-producing cells spread incorrectly through the embryo. In normal development, pigment cells start near the back of the embryo and spread through its developing skin to the belly. As the cells spread they also multiply, creating more cells, some of which are left behind to ensure all the skin is pigmented.

With piebaldism, however, the darkly colored pigment cells don’t make it as far as the belly in time to pigment the hair and skin. This results in distinctive white patches of fur and skin, usually around the furthest point from where they started. It has long been thought that pigment cells migrate directly from the back to the front and that the lack of pigmentation at the front is due to pigment cells not moving fast enough.

The article explains that new research paints a different picture and if anything, cells in piebald animals migrate faster than in normal animals, but they don’t divide as often. This means that there simply aren’t enough cells to pigment all the areas of the developing embryo.

Using this new information, scientists are exploring and evaluating a huge range of possible alternative for pattern formation and are creating a deeper understanding when it comes to the early development of cell types. The article states that these findings are also creating new opportunities to learn more about medical conditions linked to early cell positioning, including those that give rise to certain types of cancers of the nervous system and other debilitating diseases such as Waardenburg syndrome, Hirschsprung disease and others.

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