Anyone who has a cat can tell you that they have a huge variety of different coat patterns, from solid colors to intricate stripes and spots. Until recently, we didn’t know how these complex stripe patterns came to be during development. Now, scientists have discovered more about how tabby cats get their stripes.

Fur stripes are formed from hair follicles that produce different colors of hair, and hair color is determined by what type of melanin, the same pigment that causes different skin colors in people, the hair follicle uses. How do hair follicles in different regions of skin know what type of melanin to make to create a stripe pattern? Researchers noticed the first clue when looking at skin samples from embryonic cats. They observed that even before hair follicles started to develop, certain areas of skin had a thicker top layer. The thick and thin skin areas matched the striped hair color pattern that tabbies have, but the researchers could not yet tell whether the thick skin areas would turn into light or dark stripes. Some cats have a genetic mutation that causes thicker stripes of dark hair. By looking at skin samples from embryonic cats that have this mutation, the researchers could tell that the stripes of thicker skin correspond to what will become darker fur and the thin skin areas to light fur. Going one step further, the scientists found that even before the skin shows thick and thin areas, skin cells that will form a thicker skin area express a particular gene called Dkk4. Certain cat breeds have mutations in this gene, which could explain their different coat patterns.

Formation of coat pattern is an old mystery in biology, and the genetics behind the coat patterns that define different breeds of cats are unknown in many cases. These findings expand what we know about how different coat patterns can form and could be applicable to many animals besides domestic cats.

This study was led by Dr. Christopher Kaelin and Dr. Kelly McGowan, both senior scientists in Dr. Gregory Barsh’s lab. The lab is affiliated with the Stanford University department of Genetics in California and the HudsonAlpha Institute for Biotechnology in Alabama.

Managing Correspondent: Gemma Johnson

Press Articles: “We finally know what turns cats into tabbies,” Popular Science

Original Journal Article: “Developmental genetics of color pattern establishment in cats,” Nature Communications

Image Credit: Rachel Wexler

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