January 1, 2025, 8:38 am | Read time: 3 minutes
Whether ocelot, leopard, or Egyptian Mau and Bengal cat, many domestic and wild cats are spotted. But why is that? And why do scientists suspect that spotted fur is a further development of striped fur?
For many people, cats are absolutely fascinating creatures. It doesn’t matter whether they live with us as domestic cats or whether we are talking about other large and small cats, such as lions or cheetahs. Their graceful manner, self-determined nature, and the danger that lies dormant within them make cats a popular object of study in science. We know that all 41 cat species have a lot in common genetically and that our domestic cat is hardly any different from a predatory wild animal. Apparently, this also applies to the way cats develop spotted fur.
First Striped, Then Spotted Fur?
Scientists have long been fascinated by how cats develop their coat colors. The genes responsible for patterning were identified back in 2012. These were named “Taqpep” and “Edn3”. However, they appear to be involved not only in the formation of spotted fur but, first and foremost, in the formation of striped fur.
“In short: it’s complicated,” Greg Barsh, geneticist and professor emeritus, summarized his research findings in the science magazine LiveScience. Barsh and his colleagues conducted several studies on the subject before they were able to identify the genes responsible for it in 2012. While fish and other striped animals form their color via different cells, this cannot be the reason for patterns in the fur of cats. 1
“[I]n mammals, the skin and hair cells are identical throughout the body, and the color pattern is created by differences in genetic activity between the cells underlying a dark stripe, for example, and the cells underlying a light stripe,” Barsh continues.
Do Spotted Cats Have “Thick Fur”?
However, the researchers seem to have been on the right track. Because the Taqpep gene can change if both parents pass it on. Instead of stripes, the kittens then develop spotted or wavy color patterns. Interestingly, the mutated gene is most frequently found in feral cat populations.
To find out why, the team then began collecting discarded tissue from clinics that neuter feral cats; some of the removed cat uteruses contained non-viable embryos, which the researchers examined in the lab.
Through the tissue, Barsh and colleagues also found that cat embryos have thinner and thicker layers of skin in the first stage of their development, which later encode the different colors of their fur. So, do spotted cats literally “put on a thick coat”?
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Multicolored Spots – Even More Genes?
Another study identified the Taqpep gene as the key to coat patterning. A mutation in this gene causes the “marbled” pattern in domestic cats, which differs from the usual stripes (tabby pattern). The same mutation has also been identified in cheetahs. In cheetahs, however, the genes produce patches and, in places, stripes that merge into larger blocks.
Another central gene, Edn3, has been identified as a regulator of local coloration within these patterns. It controls pigment production in the skin via locally acting signaling pathways. Taqpep, on the other hand, creates a kind of “ground plan” for the patterning, which is then “painted” by Edn3. 2
However, the same gene also appears to be involved in the development of stripes and spots in many other wild cats. But why, then, do tigers almost always have stripes and not spots? In addition, leopards, Savannah, and Bengal cats also have multicolored spots, while the Egyptian Mau has tiny, dark spots. Researchers are now once again on the lookout for further genes that could finally solve the mystery of spotted fur in cats.