A. Golden is a writer and editor living in Alabama. They graduated with a B.A. in English.
What Is a Bicolor Cat?
A bicolor cat, also known as a piebald cat, is a cat with a coat consisting of one primary color combined with any amount of white. The amount of white can range from only a tiny streak to nearly the entire coat.
The word piebald is a portmanteau of magpie, a bird with black-and-white coloration, and bald, which denotes white patches. However, the term applies to coats of any solid color alongside white: black, grey, red, cream, brown, etc. Tabby patterns may also be present.
Bicolor patterns can occur in many breeds, including British Shorthair, Cornish Rex, Cymric, Exotic Shorthair, Maine Coon, Manx, Norwegian Forest Cat, Persian, and Turkish Van, as well as in common domestic cats.
The White Spotting Gene and Scale
Cats acquire bicolor patterns from the piebald, or white spotting, gene, which adds varying amounts of white to an otherwise solid-colored coat. The variation of white spotting is typically measured on a scale from 1 to 10, with 1 being the lowest amount of white and 10 being the highest. This scale can be divided into three main grades: low, medium, and high.
White Spotting Scale
- Low-grade: less than 40% of the coat is white
- Medium-grade: 40-60% is white
- High-grade: more than 60% of the coat is white
The white spotting gene, symbolized by S, is incompletely dominant. Generally speaking, if two dominant alleles (SS) are inherited, the white spotting will cover more than half of the cat’s body. If inheriting one dominant and one recessive gene (Ss), the cat will have low-to-medium grade white spotting. Two recessive genes (ss) result in little or no white.
A 2016 study discovered that the piebald gene develops in a randomized process rather than any set sequence. There is, however, a consistency in the order and location of white spotting as the amount increases. The chest and belly are typically the first areas white manifests, followed by the front paws. The white then progresses up the sides of the body, spreading to the legs and face. From here the white’s expansion is more arbitrary, reducing the remaining pigmented areas to small patches or streaks.
Note that due to the diverse nature of bicolor patterns, these categories are more of a general guide than an exact measurement. With any variation of coloring, there may be miscellaneous splotches of white that do not perfectly adhere to the definitions listed.
Low-Grade White Spotting
Coats with low-grade white spotting usually fall between grades 1 and 4 on the 1-10 scale. The most common patterns are the locket and the tuxedo.
A cat with only a single, small patch of white, called a “locket,” on the chest.
Arguably the most well-known bicolor variation, tuxedo cats have a coat that resembles—you guessed it—a tuxedo. White is limited to the chest, belly, and paws, and may show up on the face as well. The term “tuxedo cat” is most often applied to black-and-white cats, but the pattern can appear with any color.
Medium-Grade White Spotting
Medium-grade white spotting includes "true" or "standard" bicolor and mask-and-mantle coats.
A “true” or “standard” bicolor cat is one with a relatively equal ratio of white to pigment. In many official contexts, such as cat shows, these coats are simply referred to as bicolor. Outside of official contexts, the "true" and "standard" are there to differentiate this variation from the use of bicolor as an umbrella term.
Cat registry Fédération Internationale Féline (FIFe) defines an acceptable "standard" bicolor coat for cat shows by these conditions:
“The color patches must be clearly separated from each other, even in color and harmoniously distributed. At least ½ should be colored, but not more than ¾; the rest is white.”
The Cat Fancier Organization (CFA) is less specific, simply stating that “cats with no more than a locket and/or button [patch on the abdomen] do not qualify for this color class.”
Mask-and-mantle cats have the appearance of wearing a colored “mask” and cape, or “mantle.” White spotting appears on the legs, underside, shoulders, and most of the face. The mask and mantle may blend together or be separated by a small amount of white.
High-Grade White Spotting
Since the expression of white tends to become more varied as the amount increases, high-grade white spotting encompasses a broader range of patterns. The main types are cap-and-saddle, harlequin, and van.
This is a progression from the mask-and-mantle pattern in which the pigmented “mask” shrinks into a “cap” over the top of the head, and the “mantle” shrinks into a “saddle” on the lower back area. The tail may or may not be white.
A harlequin cat is loosely defined as a predominantly white cat with small, random spots of another color, commonly on the body and legs. They usually have a colored tail as well.
FIFe's cat show guidelines define a harlequin coat as the following:
“The solid colored patches must cover at least ¼, but no more than ½ of the body’s surface. Preferably the colored parts should consist of various patches surrounded by white.”
In a van pattern, color is limited to the head—usually between the ears— and the tail only; everywhere else is white. It is named after the Turkish Van breed of cat who sports the same markings.
The van pattern is actually a specific subset of the Seychellois pattern. The Seychellois pattern is divided into three variants: Septième (7th), Huitième (8th), and Neuvième (9th). The numbered names reflect the patterns’ relative locations on the white spotting scale. In other words, the degree of white in the Seychellois pattern can vary from grade 7 to grade 9.
- Seychellois Septième: white with splashes of color on the head, tail, legs, and body.
- Seychellois Huitième: white with splashes of color on the head, tail, and legs.
- Seychellois Neuvième: white with color on the head and tail only. The traditional van pattern falls under this category.
Unusual bicolor markings that do not fit any of the standard grade descriptions exist as well. Some, like the "skunk stripe" pattern, are rare mutations; others are the result of health-related conditions. Little information about these oddities is available, but Sarah Hartwell has extensive section dedicated to them on her research website Messybeast.
- Lyons, Leslie A. "Coat Colors & Fur Types." The Feline Genome Project. 30 Nov. 2004. Accessed 20 June 2018.
- Mort, R. L. et al. "Reconciling diverse mammalian pigmentation patterns with a fundamental mathematical model." Nature Communications, vol. 7, 2016. Accessed 17 June 2018.
- "Breed standards." Fédération Internationale Féline. 1 Jan. 2018. Accessed 16 June 2018.
- "Show Rules (2018-2019)." The Cat Fanciers' Association, Inc. Accessed 16 June 2018.
- Hartwell, Sarah. "Feline Depigmentation Conditions." Messybeast. 2017. Accessed 20 June 2018.
EllieMeaAndTheCats on July 31, 2020:
This helped me a lot! Thank you!
lilly on March 07, 2019:
hey i like it
silverlover on December 29, 2018:
7+ Bicolor Pattern Variations in Cats (and Why They Occur) - pets
My friend JudyвЂ™s cat is a calico cat. She has the beautiful coat associated with calico cats: distinct patches of white, black, and orange (tabby).
Before I knew anything about tricolor cats I thought that she was just a regular domestic cat with a pretty, colorful coat. But as I became more interested in all things cat, I learned that my friendвЂ™s cat is a calico. I also learned that this type of cat can have different color patterns.
I also learned that calico isвЂ¦
Not a cat breed
Calicos do not belong to any particular breed. Instead, the term refers to their color pattern.
The coloring of these felines is very specific: they must have a three-color coat. That is why they are called true tricolor cats. The most common colors are white, black, and orange or red (see below for other color combinations). Interestingly, the orange fur always has tabby markings. There is no solid orange.
By the way, the patches of each color must be very distinct. Generally, the more white fur a calico has, the more distinct the other patches are.
Another interesting fact is that not all tricolor cats are calicos. Tricolor coats also occur in other cat breeds. But again, that doesn't mean they are calicos. The Javanese and the Himalayan are two of these breeds. Their coats can have tricolored spots or points. However, these spots are much smaller than the patches of calicos.
Interestingly, even though calicos are not a specific breed they can occur in several breeds. For example, there are instances of tricolors in the Manx, American Shorthair and American Longhair breeds. Here are more cat breeds that can have calico markings.
Calicos can have different color combinations. White is always the predominant color. The second color is usually red (orange) or cream. The third color can be: black, blue, cinnamon, chocolate, fawn, or lilac (lavender). Chocolate and cinnamon occur very rarely.
Why these other colors? The so-called dilution gene causes variations of the colors red and black. If a cat has the dilution gene, his/her colors will be diluted (washed out). So, the catвЂ™s coat will have cream instead of red and blue instead of black.
Similarly, the dilution gene turns chocolate into lavender and cinnamon into fawn (a paler shade of brown with a yellow tint in it). Cats with dilute colors are called dilute calicos.
It turns out that my friendвЂ™s cat is a non-dilute calico: she possesses a beautiful coat of white, orange and black.
-Due to genetics, most calicos are female. Male calicos are very rare, and usually sterile.
-MarylandвЂ™s state cat is a calico cat.
-Some cultures consider calico cats to be bearers of good luck. Japanese sailors, for example, are said to carry calico cats on their ships as lucky talismans.
-The word calico is derived from Calicut, an Indian city where a hoarse, brightly printed fabric was produced. This cloth was also named Calicut, and it was later called Calico by European traders.
-Interestingly, the term calico was also used to describe brightly spotted horses.
-Tortoiseshell and calico are two different types of cat. See below for more information about the differences between these two cat types.
--In the UK, calicos are called tortoiseshell-and-white cats.
Difference between calico and tortoiseshell
Before I knew anything about calicos and tortoiseshells (affectionately called torties), I thought they were the same type of cat. But I learned that there is a difference between torties and calicos.
To begin with, torties have less white hair than calicos. Some torties have no white fur at all. In addition, calicos have very distinct patches of each color. By contrast, tortiesвЂ™ colors are blended and you can barely tell where one color ends and where the other color begins.
Interestingly, some tortoiseshell cats have larger amounts of white than usual, but their other two colors remain blended.
Calico gift ideas
Books on cats make great gifts for cat lovers. And if you or your friends love calicos, you might want to check:
-Cats Are Not Peas: A Calico History of Genetics by Laura L. Gould
-Calico Cats by Nancy Furstinger
-Counting on Calico by Phyllis Limbacher Tildes, Phyllis L. Tildes (Illustrator)
-Hello, Calico! (Board book) by Karma Wilson, Buket Erdogan (Illustrator)
More calico-themed gift ideas
- Posters вЂ“ These make relatively inexpensive cat lover gifts.
Paintings вЂ“ For the sophisticated art and cat lover- and if your budget allows it- a calico cat painting may be the perfect gift. Here are more cat art gift ideas.
Calendars вЂ“ Another low-cost gift idea.
Figurines вЂ“ A great idea for collectors, both seasoned and beginners.
Plush calico вЂ“ A plush kitty is a great gift idea for cat lovers of all ages.
- 1 Solid colors
- 1.1 Eumelanin
- 1.2 Sex-linked orange/red
- 1.3 Dilution and Maltesing
- 1.4 Other genes
- 2 Tabbies
- 2.1 Agouti
- 2.2 Mackerel or blotched
- 2.3 Spotted tabby
- 2.4 Ticked tabby
- 2.5 Other genes
- 3 Tortoiseshells and calicos
- 3.1 Variations
- 4 White spotting and epistatic white
- 5 Colorpoint and albinism
- 6 Silver and golden series
- 6.1 Tipped or shaded cats
- 7 Fever coat
- 8 Fur length and texture
- 8.1 Curly-coated
- 8.2 Hairlessness
- 9 See also
- 10 References
- 11 Further reading
- 12 External links
The browning gene B/b/b l codes for TYRP1 ( Q4VNX8 ), an enzyme involved in the metabolic pathway for eumelanin pigment production. Its dominant form, B, will produce black eumelanin. It has two recessive variants, b(chocolate), and b l (cinnamon), with b l being recessive to both B and b.  Chocolate is a rich brown color, and is referred to as chestnut in some breeds. Cinnamon is a lighter reddish brown.
Sex-linked orange/red Edit
The sex-linked Orange locus, O/o, determines whether a cat will produce eumelanin. In cats with orange fur, phaeomelanin (red pigment) completely replaces eumelanin (black or brown pigment).  This gene is located on the X chromosome. The orange allele is O, and is codominant with non-orange, o. Males can typically only be orange or non-orange due to only having one X chromosome. Since females have two X chromosomes, they have two alleles of this gene. OO results in orange fur, oo results in black or brown fur, and Oo results in a tortoiseshell cat, in which some parts of the fur are orange and others areas non-orange.  Male tortoiseshell cats are known to exist, but, as expected from the genetics involved, they are rare and often exhibit chromosomal abnormalities.  In one study, less than a third of male calicos had a simple XXY Klinefelter's karyotype, slightly more than a third were complicated XXY mosaics, and about a third had no XXY component at all. 
This color is known as red by breeders. Other names include yellow, ginger, and marmalade. Red show cats have a deep orange color, but it can also present as a yellow or light ginger color. Unidentified "rufousing polygenes" are theorized to be the reason for this variance. Orange is epistatic to nonagouti, so all red cats are tabbies. "Solid" red show cats are usually low contrast ticked tabbies. 
The precise identity of the gene at the Orange locus is unknown. It has been narrowed down to a 3.5 Mb stretch on the X chromosome in 2009. 
Dilution and Maltesing Edit
The Dense pigment gene, D/d, codes for melanophilin (MLPH A0SJ36 ), a protein involved in the transportation and deposition of pigment into a growing hair.  When a cat has two of the recessive d alleles (Maltese dilution), black fur becomes "blue" (appearing gray), chocolate fur becomes "lilac" (appearing light brown), cinnamon fur becomes fawn, and red fur becomes cream. The d allele is a single-base deletion that truncates the protein. 
Other genes Edit
- Barrington Brown is a recessive browning gene that dilutes black to mahogany, brown to light brown and chocolate to pale coffee. It is different from the browning gene and has only been observed in laboratory cats. 
- The Dilution modifier gene, Dm, "caramelizes" the dilute colors as a dominant trait. The existence of this phenomenon as a discrete gene is a controversial subject among feline enthusiasts.
- A mutation at the extension locus E/e (the melanocortin 1 receptor, MC1R) changes black pigment to amber or light amber. Kittens are born dark but lighten up as they age. Paws and nose still exhibit the original undiluted color, this in contrast to other diluted colors, where paws and nose have the diluted color. This phenomenon was first identified in Norwegian Forest cats. 
- Another recessive mutation at extension was discovered which causes the russet color in Burmese cats. It is symbolized as e r . Like amber cats, russet cats lighten as they age. 
- A modifying factor has also been hypothesized in shaded silver and chinchilla Persians whose fur turns pale golden in adulthood, due to low levels of phaeomelanin production. These cats resemble shaded or tipped goldens, but are genetically shaded or tipped silvers. This is probably related to the phenomenon known as "tarnishing" in silvers.
Tabby cats are striped due to the agouti gene. Their stripes have an even distribution of pigment, while the background is made up of banded hairs. Tabby cats usually show the following traits:
- M on forehead. (Visible in ticked tabby cats, but hard to discern in shaded silver/golden, and tipped cats)
- Thin pencil lines on face. (Visible in ticked tabby cats, but hard to discern in shaded silver/golden, and tipped cats)
- Black "eyeliner" appearance and white or pale fur around eyeliner.
- Pigmented lips and paws.
- A pink nose outlined in darker pigment.
- Torso, leg, and tail banding. (Torso banding disappears in the ticked tabby.)
The Agouti gene, with its dominant A allele and recessive a allele, controls the coding for agouti signaling protein (ASIP Q865F0 ). The wild-type A produces the agouti shift phenomenon, which causes hairs to be banded with black and an orangish/reddish brown, this revealing the underlying tabby pattern (which is determined by the T alleles at the separate tabby gene). The non-agouti or "hypermelanistic" allele, a, does not initiate this shift in the pigmentation pathway and so homozygotes aa have pigment production throughout the entire growth cycle of the hair—along its full length.  As a result, the non-agouti genotype (aa) is solid and has no obvious tabby pattern (sometimes a suggestion of the underlying pattern, called "ghost striping", can be seen, especially in bright slanted light on kittens and on the legs, tail and sometimes elsewhere on adults). Agouti is found on chromosome A3.
A major exception to the solid masking of the tabby pattern exists: the O allele of the O/o locus is epistatic over the aa genotype. That is, in red or cream colored cats, tabby striping is displayed despite the genotype at the agouti locus. This explains why you can usually see the tabby pattern in the orange patches of non-agouti tortoiseshell cats, but not in the black or brown patches.
However, some red cats and most cream cats show a fainter tabby pattern when they have no agouti allele to allow full expression of their tabby alleles. That is, in genetically red cats (O males and OO and Oo females) the aa does still have an effect, especially in dilute coats (when having dd genotype at the D gene locus), where the tabby pattern is sometimes not expressed except on the extremities.
Mackerel or blotched Edit
The Tabby gene on chromosome B1 accounts for most tabby patterns seen in domestic cats, including those patterns seen in most breeds. The dominant allele Ta M produces mackerel tabbies, and the recessive Ta b produce classic (sometimes or once referred to as blotched) tabbies.  The gene responsible for this differential patterning has been identified as transmembrane aminopeptidase Q (Taqpep, M3XFH7 ), which also produces the king cheetah coat variant. 
The wild-type (in African wildcats) is the mackerel tabby (stripes look like thin fishbones and may break up into bars or spots), the most common variant is the classic tabby pattern (broad bands, whorls, and spirals of dark color on pale background usually with bulls-eye or oyster pattern on flank). The classic tabby is most common in Iran, Great Britain and in lands that were once part of the British Empire and Persian Empire. 
Spotted tabby Edit
Spotted tabbies have their stripes broken up into spots, which may be arranged vertically or horizontally. A 2010 study suggests that spotted is caused by the modification of mackerel stripes, and may cause varying phenotypes such as "broken mackerel" tabbies via multiple loci. 
Ticked tabby Edit
The Ticked (Ti) locus on chromosome A1 controls the generation of ticked coats, a non-patterned agouti coat having virtually no stripes or bars but still considered a tabby coat. The Ti A is the dominant allele that produces ticked coats Ti + is the recessive one. Stripes often remain to some extent on the face, tail, legs, and sometimes the chest in heterozygotes (Ti A Ti + ) but are nearly or completely nonexistent in homozygotes (Ti A Ti A ). The Abyssinian breed is fixed for the ticked allele—all Abyssinians are homozygotes for this gene. The ticked tabby allele is ultimately dominant and therefore completely (or mostly) masks all the other tabby alleles, “hiding” the patterns they would otherwise express. 
It was once thought that Ti A is a very dominant allele of the Tabby gene called T a . 
Other genes Edit
- Other genes (pattern modifier genes) are theorized to be responsible for creating various type of spotting patterns, many of which are variations on a basic mackerel or classic pattern. There are also hypothetical factors which affect the timing and frequency of the agouti shift, affecting agouti band width and the number and quality of alternating bands of eumelanin and phaeomelanin on individual hairs.
- There is a gene not yet identified, but believed to be related to the agouti gene in the Chausie breed that produces silver-tipped black fur similar to Abyssinian ticked fur, known as "grizzled." This phenomenon is purported to have been inherited from the hybridization of the domestic cat to the jungle cat (Felis chaus).
- The inhibited pigment gene, I/i. The dominant allele (I) produces tipped hairs that are fully colored only at the tip and have a white base. This allele appears to interact with other genes to produce various degrees of tipping, ranging from deeply tipped silver tabby to lightly tipped shaded silver and chinchilla silver. The inhibitor gene interacts with the non-agouti genotype (I-aa) to produce the color known as smoke. The homozygous recessive genotype when combined with the agouti gene (iiA-), produces tabby coloration, which can vary along a spectrum ranging from a deeply patterned brown tabby, to a lighter "golden tabby", to the very lightly colored shaded or chinchilla golden colors. Orange cats with the inhibitor gene (I-O-) are commonly called "cameo".
Tortoiseshells are also known by the abbreviation "tortie". Tortoiseshells have patches of orange fur (pheomelanin based) and black or brown (eumelanin based) fur, caused by X-inactivation. Because this requires two X chromosomes, the vast majority of tortoiseshells are female, with approximately 1 in 3,000 being male.  Male tortoiseshells can occur as a result of chromosomal abnormalities such as Klinefelter syndrome, by mosaicism, or by a phenomenon known as chimerism, where two early stage embryos are merged into a single kitten.
Tortoiseshells with a relatively small amount of white spotting are known as "tortoiseshell and white", while those with a larger amount are known in North America as calicos. Calicos are also known as tricolor cats, mi-ke (meaning "triple fur") in Japanese, and lapjeskat (meaning "patches cat") in Dutch. The factor that distinguishes tortoiseshell from calico is the pattern of eumelanin and pheomelanin, which is partly dependent on the amount of white, due to an effect of the white spotting gene on the general distribution of melanin. A cat which has both an orange and non-orange gene, Oo, and little to no white spotting, will present with a mottled blend of red/cream and black/blue, reminiscent of tortoiseshell material, and is called a tortoiseshell cat. An Oo cat with a large amount of white will have bigger, clearly defined patches of red/cream and black/blue, and is called a calico. With intermediate amounts of white, a cat may exhibit a calico pattern, a tortie pattern, or something in between, depending on other epigenetic factors. Diluted calico cats with lighter coloration are sometimes called calimanco or clouded tiger. 
A true tricolor must consist of three colors: white a red, orange, yellow, or cream pheomelanin color and a black, brownish, or gray (blue) eumelanin color. Tricolor should not be mistaken for the natural gradations in a tabby pattern. The shades which are present in the pale bands of a tabby are not considered to constitute a separate color. 
- The basic tortoiseshell pattern has several different colors depending on the color of the eumelanin (the B locus), and dilution (the D locus).
- Tortoiseshell tabbies, also known as torbies, display tabby patterning on both colors. Calico tabbies are also called calibys or tabicos. 
White spotting and epistatic white (also known as dominant white) were long thought to be two separate genes, but in fact they are both on the KIT gene. White spotting can take many forms, from a small spot of white to the mostly-white pattern of the Turkish Van, while epistatic white produces a fully white cat. The Birman-specific recessive "gloving" trait is also located on the KIT gene. 
- W D = dominant white, linked to blue eyes and deafness. The deafness is due to a reduction in the population and survival of melanoblast stem cells, which in addition to creating pigment-producing cells, develop into a variety of neurological cell types. White cats with one or two blue eyes have a particularly high likelihood of being deaf.
- W S = white spotting. It exhibits codominance and variable expression heterozygous cats have somewhere between 0-50% white, and homozygous cats have between 50-100% white.
- w = wild type, no white spotting.
- w g = recessive Birman white gloving allele. 
W D causes congenital sensorineural deafness in cats. Domesticated W D cats are often completely deaf. 
The colorpoint pattern is most commonly associated with Siamese cats, but may also appear in any domesticated cat. A colorpointed cat has dark colors on the face, ears, feet, and tail, with a lighter version of the same color on the rest of the body, and possibly some white. The exact name of the colorpoint pattern depends on the actual color, so there are seal points (dark brown), chocolate points (warm lighter brown), blue points (dark gray), lilac or frost points (silvery gray-pink), red or flame points (orange), and tortie (tortoiseshell mottling) points, among others. This pattern is the result of a temperature sensitive mutation in one of the enzymes in the metabolic pathway from tyrosine to pigment, such as melanin thus, little or no pigment is produced except in the extremities or points where the skin is slightly cooler. For this reason, colorpointed cats tend to darken with age as bodily temperature drops also, the fur over a significant injury may sometimes darken or lighten as a result of temperature change. More specifically, the albino locus contains the gene TYR ( P55033 ). 
The tyrosine pathway also produces neurotransmitters, thus mutations in the early parts of that pathway may affect not only pigment, but also neurological development. This results in a higher frequency of cross-eyes among colorpointed cats, as well as the high frequency of cross-eyes in white tigers. 
- C = full color.
- cb = Burmese "sepia" pattern, similar to colorpoint but with lower contrast.
- cs = Siamese/colorpoint. It is codominant with cb cb/cs cats show a medium-contrast phenotype known as mink.
- ca = Blue-eyed albino.
- c = Pink-eyed albino.
The silver series is caused by the Melanin inhibitor gene I/i. The dominant form causes melanin production to be suppressed, but it affects phaeomelanin (red pigment) much more than eumelanin (black or brown pigment). On tabbies, this turns the background a sparkling silver color while leaving the stripe color intact, making a silver tabby. On solid cats, it turns the base of the hair pale, making them silver smoke. 
Silver agouti cats can have a range of phenotypes, from silver tabby, to silver shaded (under half the hair is pigmented), to tipped silver/chinchilla (only the very tip of the hair is pigmented). This seems to be affected by hypothetical wide band factors, which make the silver band at the base of the hair wider. Breeders often notate wide band as a single gene Wb/wb, but it is most likely a polygenic trait.
If a cat has the wide band trait but no inhibitor, the band will be golden instead of silver. These cats are known as golden tabbies. Shaded golden and tipped golden are also possible. However, there is no golden smoke, because the combination of wide band and nonagouti simply produces a solid cat.  
The genetics involved in producing the ideal tabby, tipped [fr] , shaded, or smoke cat is complex. Not only are there many interacting genes, but genes sometimes do not express themselves fully, or conflict with one another. For example, the melanin inhibitor gene in some instances does not block pigment, resulting in a grayer undercoat, or in tarnishing (yellowish or rusty fur). The greyer undercoat is less desirable to fanciers.
Likewise, poorly-expressed non-agouti or over-expression of melanin inhibitor will cause a pale, washed out black smoke. Various polygenes (sets of related genes), epigenetic factors, or modifier genes, as yet unidentified, are believed to result in different phenotypes of coloration, some deemed more desirable than others by fanciers.
Tipped or shaded cats Edit
The genetic influences on tipped or shaded cats are:
- Agouti gene.
- Tabby pattern genes (such as T a masking the tabby pattern).
- Silver/melanin inhibitor gene.
- Factors affecting the number and width of bands of color on each hair (such as the hypothetical wide band gene).
- Factors affecting the amount and quality of eumelanin and/or phaeomelanin pigment expression (such as theorized rufousing factors)
- Genes causing sparkling appearance (such as glitter in the Bengal, satin in the Tennessee Rex, grizzle in the Chausie).
- Factors to clear up residual striping (hypothetical Chaos, Confusion, Unconfused, Erase, and Roan factors).
Fever coat is an effect known in domestic cats, where a pregnant female cat has a fever or is stressed, causing her unborn kittens' fur to develop a silver-type color (silver-grey, cream, or reddish) rather than what the kitten's genetics would normally cause. After birth, over some weeks the silver fur is replaced naturally by fur colors according to the kitten's genetics.   
Cat fur length is governed by the Length gene in which the dominant form, L, codes for short hair, and the recessive l codes for long hair. In the longhaired cat, the transition from anagen (hair growth) to catagen (cessation of hair growth) is delayed due to this mutation.  A rare recessive shorthair gene has been observed in some lines of Persian cat (silvers) where two longhaired parents have produced shorthaired offspring.
The Length gene has been identified as the fibroblast growth factor 5 (FGF5 M3X9S6 ) gene. The dominant allele codes for the short coat is seen in most cats. Long coats are coded for by at least four different recessively inherited mutations, the alleles of which have been identified.  The most ubiquitous is found in most or all long haired breeds while the remaining three are found only in Ragdolls, Norwegian Forest Cats, and Maine Coons.
There have been many genes identified that result in unusual cat fur. These genes were discovered in random-bred cats and selected for. Some of the genes are in danger of going extinct because the cats are not sold beyond the region where the mutation originated or there is simply not enough demand for cats expressing the mutation.
In many breeds, coat gene mutations are unwelcome. An example is the rex allele which appeared in Maine Coons in the early 1990s. Rexes appeared in America, Germany and the UK, where one breeder caused consternation by calling them "Maine Waves". Two UK breeders did test mating which indicated that this was probably a new rex mutation and that it was recessive. The density of the hair was similar to normally coated Maine Coons, but consisted only of down type hairs with a normal down type helical curl, which varied as in normal down hairs. Whiskers were more curved, but not curly. Maine Coons do not have awn hairs, and after moulting, the rexes had a very thin coat.
There are various genes producing curly-coated or "rex" cats. New types of rex arise spontaneously in random-bred cats now and then. Here are some of the rex genes that breeders have selected for:
- r = Cornish Rex, recessive.
- gr (provisional) = German Rex, recessive. Same locus as Cornish, but proposed as a different allele. However, most breeders consider the German Rex to have r/r genotype.
- re = Devon Rex, recessive. Identified on KRT71 ( E1AB55 ). 
- ro = Oregon Rex (extinct), recessive.
- Se = Selkirk Rex, dominant although sometimes described as an incomplete dominant because the three possible allele pairings relate to three different phenotypes: heterozygous cats (Sese) may have a fuller coat that is preferred in the show ring, while homozygous cats (SeSe) may have a tighter curl and less coat volume. (sese type cats have a normal coat.) This phenomenon may also colloquially be referred to as additive dominance.
- Lp (provisional) = LaPerm, dominant: Lp/lp and Lp/Lp individuals have the same phenotype.
There are also genes for hairlessness:
- h = French hairless cat, recessive.
- hd = British hairless cat, recessive.
- Hp = Russian Donskoy and Peterbald, dominant.
- hr = Canadian Sphynx cat, recessive. Identified on KRT71. 
Some rex cats are prone to temporary hairlessness, known as baldness, during moulting.
Here are a few other genes resulting in unusual fur:
- The Wh gene (dominant, possibly incomplete) results in Wirehair cats. They have bent or crooked hair producing springy, crinkled fur.
- A hypothetical Yuc gene, or York Chocolate undercoat gene, results in cats with no undercoat. However, the proportional relationship between guard, awn, and down hair production varies greatly between all breeds.
- A recessive autosomal gene for Onion hair which causes roughness and swelling on the hairs. The swelling is due to enlargement of the inner core of medulla cells.
- A recessive autosomal gene spf for sparse fur. As well as sparse coat, the hairs are thin, straggly and contorted and there is brown exudate around the eyes and nose and on the chest and stomach. A similar condition is linked to Ornithine Transcarbamylase Deficiency in mice.
7+ Bicolor Pattern Variations in Cats (and Why They Occur) - pets
zoogle-video#handleVimeoPostMessage">On this page you will find lots of photos showing the different colors
and patterns of the Blue Eyed Pointed Ragdoll Cat.
Click any of the photos to enlarge and see the description.
There is a huge variation within color groups depending on the
pattern of the cat as you will see.
Ragdolls are accepted for registration and exhibition as purebred,
blue-eyed pointed cats in the following colors:
- Red (flame)
- Blue Tortie
- Seal Tortie
- Lilac Tortie
- Chocolate Tortie
Within each of those colors there can be these distinct
There is one more variation that can occur in any combination of colors
and patterns above. This is the
- Lynx or Tabby which then makes a 'Tortie' cat a 'Torbie'
Many of these colors and patterns are not fully visible until the cat reaches
maturity at approx. 3 years of age.
To Sleep or Not to Sleep
Although they are biologically wired to be most active during twilight, some cats carry their exuberant behavior into the wee morning hours. After all, it's not as if they're perky from sleeping sixteen hours in a row. Most cats wake their pet parents up from a deep sleep at least once per night — a habit that can drive their humans batty. It's no fun to walk around sleep-deprived. (This pattern of nighttime antics typically prompts the "Are cats nocturnal?" question.)
This is where a cat's sleeping pattern comes into play. Sleeping (and restful dreaming) for cats is not the same as for their human family members, explained Animal Planet. Cats "do experience both non-REM and REM sleep, but for cats, 'asleep' is not 'off the clock.' Cats are always on the alert, even when they're dozing. If a strange noise wakes them up, they're almost instantly aware and fully operational. It's an ability that cats (and wild animals in general) depend on to stay safe, and fed, in [nature]." You may notice this in your own home when, say, your furry friend is in a seemingly deep sleep far away in the corner of the house but comes running at the sound of her cat food container being cracked open.
House cats don't depend on hunting for their source of food, but this doesn't mean those instincts are gone. As genetics professor, Dr. Wes Warren, told Smithsonian Magazine, "cats have retained their hunting skills, and they're less dependent on humans for their source of food." This is why your kitty will "hunt" her toys, kibble, and cat treats. Her hunting instincts are intrinsically connected with her crepuscular nature, resulting in a fascinating form of indoor behavior that aligns with the behavior of her ancestors — it's like having your very own miniature lion.