in ,

Cat Colors and How they Occur

8 Cat Colors

Share this image on your site!

Everything you wanted to know about cat colors and markings.

 

Cat Markings

The ‘tabby’ is used to describe a cat with stripes or irregular patterns and comes from the Spanish word tabi – a kind of cloth with irregular tie-die-like markings.

How Cat Colors are made…

Table of Contents

The Color-Conformation Genes

The color-conformation genes determine the color, pattern, and expression of the coat. Since these characteristics are among the most important of the cat’s features, at least from a breeding point of view, more emphasis is given the color conformation genes than the others.

These genes fall into three logical groups: those that control the color, those that control the pattern, and those that control the color expression. Each of these groups contains several differing but interrelated genes.

The Color Gene

The first of the genes controlling coat color is the color gene. This gene controls the actual color of the coat and comes in three alleles: black, dark brown, or light brown. This three-level dominance is not at all uncommon: the albinism gene, for example, has five levels.

The black allele, B, is wild, is dominant, and produces a black or black-and-brown tabby coat, depending upon the presence of the agouti gene. Technically, the black allele is an almost-black, super-dark brown that is virtually black; true black is theoretically impossible, but often reached in the practical sense (so much for theory).

The dark-brown allele, b, is mutant, is recessive to black but dominant to light brown, and reduces black to dark brown.

The light-brown allele, bl, is mutant, is recessive to both black and dark brown, and reduces black to a medium brown.

The Color-Density Gene

The second of the genes controlling the coat color is the color-density gene. This gene controls the uniformity of distribution of pigment throughout the hair and comes in two alleles: dense, D, and dilute, d.

The dense allele, D, is wild, is dominant, and causes pigment to be distributed evenly throughout each hair, making the color deep and pure. A dense coat will be black, dark brown, medium brown, or orange.

The dilute allele, d, is mutant, is recessive, and causes pigment to be agglutinated into microscopic clumps surrounded by translucent unpigmented areas, allowing white light to shine through and diluting the color. A dilute coat will be blue (gray), tan, beige, or cream.

The Orange-Making Gene

The second of the genes controlling coat color is the orange-making gene. This gene controls the conversion of the coat color into orange and the masking of the agouti gene and comes in two alleles: non-orange and orange.

The non-orange allele, o, is wild and allows full expression of the black or brown colors. The orange allele, O, is mutant and converts black or brown to orange and masks the effects of the non-agouti mutation of the agouti gene (all orange cats are tabbies).

This gene is sex-linked; it is carried on the X chromosome beyond the limit of the Ychromosome. Therefore, in males there is no homologous pairing, and the single orange-making gene stands alone. As a result there is no dominance effect in males: they are either orange or non-orange. If a male possesses the non-orange allele, o, all colors (black, dark brown, or light brown) will be expressed. If he possesses the orange allele, O, all colors will be converted to orange.

In females there is a homologous pairing, one gene being carried on each of the two Xchromosomes. These two genes act together in a very special manner (as a sort of tri-state gene), and again there is no dominance effect.

If the female is homozygous for non-orange, oo, all colors will be expressed. If she is homozygous for orange, OO, all colors will be converted to orange. It is when she is heterozygous for orange, Oo, that interesting things begin to happen: through a very elegant process, the black-and-orange tortoiseshell or brindled female is possible.

Shortly after conception, when a female zygote is only some dozens of cells in size, a chemical trigger is activated to start the process of generating a female kitten. This same trigger also causes the zygote to ‘rationalize’ all the sex-linked characteristics, including the orange-making genes. In this particular case, suppression of one of the orange-making genes in each cell takes place in a not-quite-random pattern (there is some polygene influence here). Each cell will then carry only one effective orange-making gene.

Since the zygote was only some dozens of cells in size at the time of rationalization, only a few of those cells will eventually determine the color of the coat (the orange-making genes in the other cells will be ignored). If the zygote were homozygous for non-orange, oo, then all cells will contain o, and the coat will be non-orange. Likewise, if the zygote were homozygous for orange,OO, then all cells will contain O, and the coat will be orange. If, however, the zygote were heterozygous, Oo, then some of the cells will contain O and the rest of the cells will contain o. In this case, those portions of the coat determined by O cells will be orange, while those portions determined by o cells will be non-orange. Voila! A tortoiseshell cat!

A female kitten has two X chromosomes, and therefore two orange-making genes, one from each parent. Assuming for the sake of discussion an equal likelihood of inheriting either allele from each parent—an assumption that is patently false, but used here for demonstration only—then one quarter of all females would be non-orange, one-quarter would be orange, and one-half would be tortoiseshell. A male kitten, on the other hand, has only one X chromosome, and therefore only one orange-making gene. Keeping the same false assumption of equal likelihood, then one-half of all males would be non-orange and one-half would be orange. This means that there would be twice as many orange males as females if our assumption were correct.

Our equal-likelihood assumption is not correct, however. The orange-making gene is located adjacent to the centromere and is often damaged during meiosis. This damage tends to make an orange allele into a non-orange allele, giving the non-orange allele a definite leg up, so to speak, in a 7:3 ratio. This means that among female kittens 49% will be non-orange, 42% will be tortoiseshell, and only 9% will be orange, while among male kittens 70% will be non-orange and 30% will be orange: there will be more than 3 times as many orange males as females. That’s why there are so many Morris-type males around.

Since a male has only one orange-making gene, there cannot be a male tortie. An exception to this rule is the hermaphrodite, which has an XXY genetic structure. Such a cat can be tortie, since it has two X chromosomes, but is almost invariably sterile. In fact, despite the presence of male genitalia, a hermaphrodite is also an underdeveloped female, and may have both ovaries and testes, with neither fully functional.

The Eight Cat Colors

All possible expressions of the color, orange-making, and color-density genes produce the eight basic coat colors: black, blue (gray), chestnut or chocolate (dark-brown), lavender or lilac (tan), cinnamon (medium brown), fawn (beige), red (orange), and cream.

The brown and dilute colors are rarer (hence generally more prized) because they are recessive. A table of all possible combinations of the three genes controlling color will show all eight basic coat colors, among which are six female or twelve male black cats but only one female or two male fawn.

Note that although tortoiseshell females are two-color they introduce no new colors.

It may also be noted that red and cream dominate any of the true (black or brown) colors: a red coat is red regardless of whether the color gene is black, dark brown, or light brown. The color gene is masked by the orange-making gene. This, coupled with the fact that males are either red or non-red require that the color chart show oO and Oo as distinctly separate. A male has only the first of the two genes: o from oO or O from Oo. In some texts, the orange-making genes are indicated as o(O) and O(o) to emphasize the sexual distinction.

 SexBBBbBblbbbblblbl
ooDDM/FBlkBlkBlkDBrDBrMBr
ooDdM/FBlkBlkBlkDBrDBrMBr
ooddM/FGryGryGryTanTanBge
OoDDM
F
Red
Blk/Red
Red
Blk/Red
Red
Blk/Red
Red
DBr/Red
Red
DBr/Red
Red
MBr/Red
OoDdM
F
Red
Blk/Red
Red
Blk/Red
Red
Blk/Red
Red
DBr/Red
Red
DBr/Red
Red
MBr/Red
OoddM
F
Crm
Gry/Crm
Crm
Gry/Crm
Crm
Gry/Crm
Crm
Tan/Crm
Crm
Tan/Crm
Crm
Bge/Crm
OODDM/FRedRedRedRedRedRed
OODdM/FRedRedRedRedRedRed
OOddM/FCrmCrmCrmCrmCrmCrm

The Eight Cat Colors

The Albinism Gene

The first of the color-conformation genes affect coat pattern is the albinism gene. This gene controls the amount of body color and comes in five alleles: full color, C, Burmese, cb, Siamese,cs, blue-eyed albino, ca, and albino, c.

The full color allele, C is wild, is dominant, and produces a full expression of the coat colors. This is sometimes called the non-albino allele.

The Burmese allele, cb, is mutant, is recessive to the full color allele, codominant with the Siamese allele, and dominant to the blue-eyed albino and albino alleles, and produces a slight albinism, reducing black to a very dark brown, called sable in the Burmese breed, and producing green or green-gold eyes.

The Siamese allele, cs, is mutant, is recessive to the full color allele, codominant with the Burmese allele, and dominant to the blue-eyed albino and albino alleles, and produces an intermediate albinism, reducing the basic coat color from black/brown to a light beige with dark brown ‘points’ in the classic Siamese pattern and producing bright blue eyes.

The Burmese and Siamese alleles are codominant, that is they each have exactly as much dominance or recessivity. It is possible to have one of each allele, cbcs, producing a Siamese-patterned coat with a darker base body color and turquoise (aquamarine) eyes: the Tonkinese pattern.

The blue-eyed albino allele, ca, is mutant, is recessive to the full color, Burmese and Siamese alleles and dominant to the albino allele, and produces a nearly complete albinism with a translucent white coat and very washed-out pale blue eyes.

The albino allele, c, is mutant, is recessive to all others, and produces a complete albinism with a translucent white coat and pink eyes.

The albinism genes combine in some rather interesting ways:

Notice how the dominance characteristics among the alleles are normal except for the combination of Burmese and Siamese, which produce the Tonkinese pattern.

 Ccbcscac
Cnormalnormalnormalnormalnormal
cbnormalBurmeseTonkineseBurmeseBurmese
csnormalTonkineseSiameseSiameseSiamese
canormalBurmeseSiameseBE AlbinoBE Albino
cnormalBurmeseSiameseBE AlbinoAlbino

The Albinism Gene

The Agouti Gene

The next gene controlling the pattern of the coat is the agouti gene. This gene will control ticking and comes in two alleles: agouti, A, and non-agouti, a.

The agouti allele, A, is wild, is dominant, and produces a banded or ticked (agouti) hair, which in turn will produce a tabby coat pattern.

The non-agouti allele, a, is mutant, is recessive, and suppresses ticking, which in turn will produce a solid-color coat. This gene only operates upon the color gene (black, dark brown, or light brown) in conjunction with the non-orange allele of the orange-making gene and is masked by the orange allele of the orange-making gene.

The Tabby Genes

The last of the genes affecting the coat pattern is the tabby gene. This gene will control the actual coat pattern (striped, spotted, solid, etc.) and comes in three alleles: mackerel or striped tabby, T, Abyssinian or all-agouti-tabby, Ta, and blotched or classic tabby, tb.

The mackerel-tabby allele, T, is wild, is co-dominant with the spotted tabby and Abyssinian alleles and dominant to the classic-tabby allele, and produces a striped cat, with vertical non-agouti stripes on an agouti background. This is the most common of all patterns and is typical grassland camouflage, where shadows are long and strait.

A spotted tabby is genetically a striped tabby with the stripes broken up by polygene influence. There is no specific ‘spotted-tabby’ gene. This spotted coat is a typical forest camouflage, where shadows are dappled by sunlight shining through the trees. Do not confuse the spots of our domestic cats with the rosettes of the true spotted cats: entirely different genes are involved.

The Abyssinian allele, Ta, is mutant, is codominant to the mackerel-tabby allele and dominant to the classic-tabby allele, and will produce an all-agouti coat without stripes or spots. This all-agouti coat is a basic type of bare-ground camouflage, seen in the wild rabbit and many other animals.

Funny Cat Videos

Maine Coon Video – Fight Compilation

Two Faced Cat Funny Looking Cats

11 Funny Looking Cats