Our beautiful domestic cats come fabulously clothed in hundreds of color, pattern and coat varieties, a pretty amazing feat for a species that developed from a rather drab-looking desert animal. The African wildcat, the predecessor of our modern domestics, is a shorthaired sandy brown cat with Abyssinian-type ticking and tabby stripes. This color and pattern combination acts as effective camouflage in the cat’s native desert environment.
After cats began their association with humans, however, they were transported into other areas and climates, and Mother Nature did the rest – spontaneous genetic mutation brought us the myriad colors, patterns and coat varieties we enjoy today. Because of these mutations, our feline friends come in hundreds of color and pattern combinations. Humans also played a role in coloring outside the bloodlines through selective breeding.
While all of these choices are great for the cat lover who likes variety, they also can be confusing. What does a “lilac” cat look like? What’s the difference between a tortoiseshell and a calico? And just what the heck is a particolor? Read on for a short course in cat color and pattern.
A cat’s color depends upon the presence of pigmentation in the epidermis. For cats, only two pigments exist: black and red. All cats, no matter what color they are on the outside, are genetically either black or red, or in females, a combination of the two. All other colors result from other genetic factors or modifiers acting on these two pigments. Pigments are produced in cells called melanocytes, and the distribution and number of these cells are determined by the cat’s genetic makeup. These cells pass the pigment onto the cat’s hair, skin and eyes, and create the pattern and color.
Three specific genes are essential to the cat’s colorful exterior: pigment, color and density. The pigment gene determines the amount of pigment that’s distributed over the cat’s body. The color gene determines the intensity of the cat’s color. The density gene determines the density of the pigmentation; the more densely packed the pigment, the darker the color will be. For example, in order for a cat to appear black, the cat must possess three genes: B for black pigmentation, D for dense coloration, and C for full color. These are all dominant genes. However, these genes have corresponding recessive mutations that can change the cat’s appearance.
The gene for red (also called orange) is carried on the X chromosome, and that’s why it’s called a sex-linked color. Females have two X chromosomes, while males have one X and one Y chromosome. Since the X chromosome is longer than the Y, no location for the red gene exists on the Y chromosome. Therefore, male cats with their one X chromosome always express whatever color gene is present on that chromosome. If the gene is red, he will be a red tabby. If he receives the black gene he will be black or one of its variations, depending upon his genetic makeup. Females, on the other paw, can have both the gene for red and the gene for black, which gives us the colorful tortoiseshell with patches of both colors. Male cats can only be tortoiseshell if they are born with an extra X chromosome, a very rare occurrence. However, male tortoiseshells are not extremely valuable as is sometimes thought.
The Tabby Pattern
When talking about cats, “pattern” refers to the color distribution on a cat’s coat that forms a particular pattern, such as tabby stripes. Just as all cats are genetically black or red, all cats are genetically tabbies, no matter what pattern they appear to be on the outside. All possess one or more of four tabby genes: mackerel, classic, ticked and spotted. Although these patterns are quite different in appearance, they are all variations of the mackerel tabby from which the others arose.
The Seven Ancient Mutations
So now we know all cats are tabbies and are either black or red (or both if female). However, the presence of other genes can mask the stripes and cause changes in the cat’s coloration. Researchers have identified seven mutations that occurred many years ago, when felines had only recently become so-called domestic animals. These mutations are not the only ones that affect color and pattern, but they are essential for the myriad color, pattern, and coat varieties we see in cats today. They are:
A system of internationally recognized symbols was established to make it easier to understand the feline color genes and relationships to one another. Capital letters indicate dominant genes while lower case letters represent recessive genes.
Today’s Colors and Patterns
The mixing and matching of these genes gives us the more than 300 color and pattern combinations we see in cats today. Since so many exist, cat color and pattern is generally broken into five divisions or categories to make it easier to organize. These divisions are solid, tabby, shaded, particolor and pointed.
In the cat fancy, a solid-colored cat is any cat that is one solid color without recognizable stripes, spots, ticking, patches of white or shading. These cats are sometimes called “self colored,” although this term is more commonly used in Great Britain. Solid-colored cats can be found in many breeds. In some breeds, breeders have worked very hard to eliminate any residual tabby striping and make the coat a consistent color.
Common solid colors are:
Tabbies can be found in many breeds, as well as in many random-bred domestic cats. Five varieties exist:
Shaded and Smoke
Shaded and smoke varieties (also called the silver group) all possess darker colored hair tips overlying a paler under color or ground color, giving the coat a contrasting or shimmering appearance. This effect is created by the dominant inhibitor gene (I), which inhibits the pigmentation in the hair. These varieties come in many colors, including black, blue, red and cream, and patterns such as tabby and tortoiseshell.
The golden color group is similar to the silver, except that the ground color is a rich cream instead of white. This effect is created by polygenes rather than the inhibitor gene. (Polygenes, which alone exert minor influence on a cat’s color, produce larger effects when grouped together.) Goldens can be seen in breeds such as the Persian, where the long fur gives this pattern a particularly spectacular look.
Three types exist:
Depending upon the cat association, a particolor is a cat that has patches of two or more colors, or that has any color or pattern combined with white. Some of the most common particolors include:
In the pointed color pattern (also called the Siamese or Himalayan pattern), the hair contains little pigment, but the “points” of the body (face, tail, feet and ears) contain more and therefore appear darker. Even at the darkest points of the body, however, the pigmentation is diminished so that, for example, black appears dark brown. The amount of pigment distributed in the hairs depends on temperature – the cooler the temperature the more pigment is produced. The skin temperature of the body’s extremities is a few degrees lower than the rest of the body, and therefore attracts more pigmentation. The pointed pattern can be found in many breeds, but is most commonly associated with the Siamese and other Oriental breeds and with the Himalayan. Common colors include: