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There is a lot of confusion about tricolored cats. This FAQ is meant to clear up some of the confusion, explain what is and what is not a tricolored cat, and how a true tricolor occurs.
A true tricolor must have one of its colors derived from the red gene -- either red (orange) or cream (kind of a light, orangy beige, not unlike the color many people call "ginger"). If it does not have one of these two colors, it is not a true tricolor. The second color must be white, and the third color must be black, blue (a blue-gray), chocolate, lilac (a pale rose-beige), cinnamon, or fawn (a pale buff color). Black and blue are by far the most common.
Some cats may appear to have three colors, but in fact may only have two. There is a designation called "bicolor" where the cat has a significant portion of white fur, but the rest of the cat is either a solid color such as black, blue, red, or a patterned color such as brown tabby, silver tabby (what many people call "tiger"), blue tabby, etc.
A white cat with patches of tiger stripe might appear to have three colors -- white, black, and gray -- but because one of the three colors is not red or cream, it is not a true tricolor. It's defined (colorwise) as a tabby and white. A white cat with red or cream tabby patches is not a true tricolor either; only one of the colors may be red or cream in a true tricolor.
In some rare cases, a Siamese-type pointed cat may appear to be a tricolor because of white patches on its body. These cats are mixed-breed, as significant white spotting is not found in the Siamese breed (although some small bits like a little white spot on the toes is found; this is considered a disqualification for showing). In this case, the cat is not a true tricolor either -- it's a seal point and white, or a blue point and white, or a chocolate point and white. The only exception to this is found in breeds such as the Himalayan, Colorpoint Shorthair and Javanese, which allows the points themselves to be tricolored (what are called "tortie points"). But that's a whole other story. On a pointed cat, if the points themselves do not include three colors -- white, red or cream, and one other color -- it is not a true tricolor.
Cats (along with humans, dogs, armadillos, weasels, mice, and other creatures) have two sex chromosomes. Chromosomes are the vehicles for genes, and genes define traits like coat color, fur length, eye color -- everything that makes the cat what it is.
Sex chromosomes define gender. There are two sex chromosomes (stands to reason, what?), designated X and Y. Each parent contributes one sex chromosome, and these determine the gender of offspring. Females produce only X chromosomes in the form of their egg, but males produce both X and Y chromosomes, propelled in sperm. It's the male's contribution that determines whether an offspring is male or female (if only Henry VIII had known . . .).
Females produce eggs: Males produce sperm: ***** ***** *** *** * X * * X * * X ****** * Y ****** ***** ***** *** ***These eggs and sperm also carry one half of the parent's genetic material, which explains inheritance. Eggs and sperm do not carry the same combination of genes, which explains why all of our offspring don't look identical to one another.
When egg and sperm meet, they combine their traits to form a single entity, not unlike pulling two halves of a zipper together. They also combine their sex chromosomes.
If an X sperm meets the X egg, they produce an XX, or a female.
If a Y sperm meets the X egg, they produce an XY, or a male.
(Since there is no such thing as a Y egg, no YY is possible.)
The gene that determines red or orange coloration in cats is designated as O (for orange).
O = orangeIf the cat inherits an O pattern proper for its gender (I'll explain that in the following sections), the cat will be red or orange (I'll just continue to call it orange, even though most cat associations refer to this as red). This orange will cover up all other colors, except pure white. If the cat inherits an o pattern proper for its gender, it won't be orange.
o = non-orange
OY = orange catThese are the only possibilities for an XY cat.
oY = non-orange cat
However, here's where things get exciting.
In most genes, the capital letter designation is for dominant genes, and the small letter designation is for recessive genes. In most genes, if the cat gets one dominant gene and one recessive gene, whatever is the dominant gene will show up and the recessive gene won't actually appear on the cat. The cat is said to "carry" the recessive gene, which means s/he can pass it on to offspring.
So by that rule, if the female cat gets one O and one o (Oo), she should be orange, right?
Not with this gene.
With the O gene, the O and o actually combine their efforts, displaying both orange and non-orange, along with white. This is called a mosaic. This creates the true tricolor -- the calico or tortoiseshell. You must have the combination of the O and the o to create this, which means the cat must have two genes. Since only Xs can carry the O gene, the cat must have two X genes -- or in most cases, be a female.
OO = orange cat
oo = non-orange cat
Oo = tricolored cat
Sometimes, a male cat will get three sex chromosomes instead of two. This is a genetic anomaly. Genetics is all about pairs; you should only be able to have two of any genes, two of any chromosomes, residing in any individual. Although in some cases there are more genes than two possible for a given trait (like all the possible eye or hair colors on people), only two traits can actually sit there. It's sort of like owning a Geo Metro convertible: you might have more than two who want a ride, but you can only fit two in it.
Well, sometimes, weird things happen in genetics, and you get an extra gene or chromosome in there.
Sometimes, these duplications can have negative effects. For example, Down syndrome in humans is caused by a duplication of Chromosome 23, where there are three chromosomes instead of two. Animals are only meant to have a certain number of chromosomes; in this case, having a "spare" isn't good.
In cats (as well as other creatures, including humans), sometimes there is an extra sex chromosome. Some can be invisible and never detected.
A male cat who is a tricolor must have two X chromosomes to carry the Oo pattern. Thus, the cat must be at least an XXY. In humans, this pattern is known as Klinefelter's syndrome. One result of this syndrome is that the male has trouble with developing secondary sex characteristics and is usually sterile. However, unlike Klinefelter in human, an XXY male cat will usually not have any outward signs of its genetic makeup, unless it's a rare male tricolor.
Although a male tricolor almost certainly sterile, you will still want to neuter such a cat to reduce such undesirable traits such as spraying and aggression.
The difference between a calico and a tortoiseshell is this:
With a calico, there is a significant amount of white, and the two colors are broken up into distinct patches. This has to do with the interaction of white spotting.
With a tortoiseshell, the three colors are blended and don't form distinct patches. A tortoiseshell may have significant portions of white as well, but the remaining colors are blended (this particular pattern is called a tortoiseshell and white).
A torbie, or patched tabby, is a tortoiseshell where the tabby pattern is very distinct all over the cat. A calico or tortoiseshell may have distinct tabby pattern on the red or cream patches (has to do with another gene we won't get into at this juncture), but no patterning on the other color. This isn't a torbie. A torbie is clearly patterned all over the cat -- though never on the white.
Second color is: red or cream
Third color is: black, blue, chocolate, lilac, cinnamon, or fawn. Black and blue are by far the most common in domestic cat populations; chocolate is fairly rare, and cinnamon is almost unheard of. But they're worth mentioning. I'm not going to go into a lot of detail on the inheritance of black, blue, chocolate, lilac, cinnamon, and fawn. It's their relationship to the red gene that we're discussing in this FAQ. That's the subject of another FAQ.
These colors combine in very distinct ways. You can't have a chocolate and cream, or a blue and red, or a black and cream.
There is a gene called the dilution gene which in appearance "washes out" a color and makes it a lighter version. In dominant form (DD or Dd), the cat is normal colored. In recessive form (dd) the cat's color is diluted.
Color Normal (DD or Dd) Diluted black black blue chocolate chocolate lilac or lavender cinnamon cinnamon fawn red red creamIf the cat is diluted, all its colors are diluted. If the cat is not diluted, none of its colors are diluted.
So you can only have a certain number of possible combinations, based on the fact that you must have one color from each of the three, and you must have either all dilution or no dilution.
Just a note: tortiseshells and their dilute counterparts may have very, very little white present. It's the combination of the red or cream with black, chocolate, or cinnamon that's important here.
calico (black, red, and white patches)
tortoiseshell (black, red and white mixed up)
chocolate calico/tortoiseshell (chocolate, red and white)
cinnamon calico/tortoiseshell (cinnamon, red, and white)
dilute calico (blue, cream, and white patches)
bluecream (blue, cream, and white swirls)
lilac-cream or lilac calico (lilac, cream, and white)
fawn-cream or fawn calico (fawn, cream, and white)
And of course, you can have any of these "and white," except for calico, which already has significant white spotting from the gene that causes the "and white."
Cats who do not have one of the following combinations are not a true tricolor (although tortiseshells and their dilute counterparts may have a negligible amount of white):