I wrote a few weeks ago about the seven genes that control your cat’s fur color. It turns out that scientists have been doing more advanced research on fur-color genetics, and recent findings make it even more obvious how closely related our domestic cats and their wild cousins are.
The African cheetah, the world’s fastest land mammal, has tawny fur and small black spots. But there’s a much rarer species, the king cheetah, whose coat pattern is similar to the classic blotched tabby pattern.
After years of research, two teams of scientists have discovered that the gene responsible for turning the spotted fur of the African cheetah into the ink-spill pattern of the king cheetah is the same one that turns a mackerel-striped tabby cat into a blotched "classic" one.
A couple of years ago scientists discovered the gene called Taqpep (the one that produces the T, Ta, and Tb alleles I talked about in my fur article) and determined that the alleles of this gene are present in all striped and blotched tabby cats, as well as cheetahs. But they became confused when they found that Taqpep is present in low levels in dark as well as light areas of the fur.
An important clue came when researcher Kelly McGowan discovered that tabby markings appear when the fetus is seven weeks old, when some hair follicles begin producing high levels of melanin (and therefore sprout dark hairs) and others don’t. But that raised another question: What gene controls the level of melanin produced by hair follicles?
That’s when Lewis Hong came into the picture. He found 60 genes that vary in their activity levels between the yellow and black parts of a cheetah’s skin. One of these, Edn3, produces a hormone that speeds up the growth and division of melanocytes, the cells that make the melanin.
But what about Taqpep? The researchers don’t know exactly what that gene does, but they believe it plays a role in tabby striping. They believe Taqpep creates zones in the skin of fetal cats that determine how active Edn3 will be, which then determines the number of melanocytes — and thus, the striping or spotting pattern
When the Taqpep gene has the Tab mutation, it sets up wider and more erratic zones of darkening, which leads to the blotched fur of the classic tabby and the king cheetah.
There’s a lot more to the story, so I’d encourage you to read the source article if you’re interested.
Source: Discover Magazine
