In 1952, Turing described a way to explain mathematically how patterns can spontaneously emerge in nature. To find out how these cells actually make a pattern of stripes on a cat’s body, the team turned to Alan Turing, computer scientist and founder of mathematical biology. ( Learn surprising things you never knew about your cat.) A spontaneous pattern develops Alterations can also occur in pigmentation: An all-black coat, for example, results when pigment cells that should have made colors only produce dark pigment. But mutations often occur, resulting in other coat colors and patterns, such as white spots or thinner stripes. When everything goes as planned, cells with DKK4 eventually become the dark markings that make tabby cats tabbies. You are the area where dark hair needs to grow.”
GREY TABBY CAT SKIN
When they looked at how cells expressed DKK4 in embryos of about 20 days old, they discovered that the cells involved were the ones that formed the thick skin pattern a few days later.īarsh explains that DKK4 is also a messenger protein, called a “secreted molecule,” which signals to other cells around it, essentially saying, “You are special. Among these, the gene that differed the most was the elaborately named Dickkopf WNT Signaling Pathway Inhibitor 4, or DKK4. To get a closer look, the team analyzed embryos’ individual skin cells and found two different types, each of which expressed separate sets of genes. ( Read more about little-known small wildcats.) She was especially surprised to find such a pattern so early in an embryo’s development, long before the presence of hair follicles and pigment, which are the keys to coloring in animals. When McGowan examined the skin cells of embryos that were 25 to 28 days old under the microscope, she noticed that thicker areas of skin were interspersed with thinner areas, creating a temporary color pattern that resembled the tabby coloring of an adult cat. Cat cells of a different stripeĪs part of an ethically approved research protocol, Barsh Christopher Kaelin, a geneticist at Stanford University and HudsonAlpha senior scientist Kelly McGowan collected nearly a thousand embryos that would otherwise have been discarded from veterinary clinics that spay feral cats, many of which are pregnant when admitted. He didn’t have modern genetics, but he turned out to be right: It’s an inherited genetic abnormality. ( Read how house cats domesticated themselves.) During development, he said, species sometimes acquired inconsequential changes, like hair color, because they were linked to other, more useful changes. Charles Darwin, for example, proposed that most deaf cats were white with blue eyes. The genetics behind the colors and patterns of domestic cats have long intrigued scientists. This is likely to be the case in this situation as well.” But the discovery is amazing in another way too, he says: “Biology uses the same sets of tools over and over again, so it's very rare to find something that does not apply more broadly to lots of other situations. “There the satisfaction of understanding something a little bit more about the world,” says study leader Greg Barsh, an investigator at the HudsonAlpha Institute for Biotechnology, a research facility based in Huntsville, Alabama. But the stripes themselves likely originate from the domestic cat’s direct ancestor, the striped Near Eastern wildcat.
The word “tabby” derives from al-‘Attābiyya, a quarter in Baghdad that produced a fine, striped silk taffeta in the 16th century. This unique genetic process may be the same mechanism that creates stripes and spots in wild felines, the authors theorize.
The early skin cells even mimic tabby stripes under the microscope, a discovery never seen before in embryonic cells. In a study published this week in Nature Communications, scientists report that the genes that set up the tabby pattern are activated in an embryo’s skin cells before the cat’s fur develops. Of the nearly 60 million pet cats in the United States, one of the most common is the classic tabby-a coat pattern that features stripes, dots, and swirls and what looks like an M imprinted on the cat’s forehead.Īs popular as tabbies are (think Garfield the cat), scientists know little about how they get this distinctive appearance.
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