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  • Calico cats are domestic cats with a spotted or parti-colored coat that is predominantly

  • white, with patches of two other colors. Outside of North America, the pattern is more usually

  • called tortoiseshell-and-white. In the province of Quebec, they are sometimes called chatte

  • d'Espagne cat of Spain'). Other names include brindle, tricolor cat, mi-ke, and lapjeskat;

  • calicoes with diluted coloration have been called calimanco or clouded tiger. Occasionally,

  • the tri-color calico coloration is combined with a tabby patterning. This calico patched

  • tabby is called a caliby.

  • "Calico" refers only to a color pattern on the fur, not to a breed. It is absent from

  • lists of breeds. Among the breeds whose standards allow calico coloration are the Manx, American

  • Shorthair, British Shorthair, Persian, Japanese Bobtail, Exotic Shorthair and Turkish Van.

  • Because genetic determination of some coat colors in cats is linked to the X chromosome,

  • calicoes are nearly always female. Because of the genetics involved, calico males are

  • rare, and generally have impaired vitality and are almost always sterile.

  • History The coat pattern of calico cats does not define

  • any breed, but occurs incidentally in cats that express a range of color patterns; accordingly

  • the effect has no definitive historical background. However, the existence of patches in calico

  • cats was traced to a certain degree by Neil Todd in a study determining the migration

  • of domesticated cats along trade routes in Europe and Northern Africa. The proportion

  • of cats having the orange mutant gene found in calicoes was traced to the port cities

  • along the Mediterranean in Greece, France, Spain and Italy, originating from Egypt.

  • Genetics

  • In genetic terms calico cats are tortoiseshells in every way, except that in addition they

  • express a white spotting gene. There is however one anomaly: as a rule of thumb the larger

  • the areas of white, the fewer and larger the patches of ginger and dark-or-tabby coat.

  • In contrast a non-white-spotted tortoiseshell usually has small patches of color or even

  • something like a salt-and-pepper sprinkling. This reflects the genetic effects on relative

  • speeds of migration of melanocytes and X-inactivation in the embryo.

  • Serious study of calico cats seems to have begun about 1948 when Murray Barr and his

  • graduate student E.G. Bertram noticed dark, drumstick-shaped masses inside the nuclei

  • of nerve cells of female cats, but not in male cats. These dark masses became known

  • as Barr bodies. In 1959, Japanese cell biologist Susumu Ohno determined the Barr bodies were

  • X chromosomes. In 1961, Mary Lyon proposed the concept of X-inactivation: one of the

  • two X chromosomes inside a female mammal shuts off. She observed this in the coat color patterns

  • in mice. Calico cats are almost always female because

  • the locus of the gene for the Orange/non-orange coloring is on the X chromosome. In the absence

  • of other influences, such as color inhibition that causes white fur, the alleles present

  • in those orange loci determine whether the fur is orange or not. Female catslike

  • all female placental mammalshave two X chromosomes. In contrast, male placental

  • mammals, including chromosomally stable male cats, have one X and one Y chromosome. Since

  • the Y chromosome does not have any locus for the orange gene, there is no chance that such

  • a male could have both orange and non-orange genes together, which is what it takes to

  • create tortoiseshell or calico coloring. One exception is that in rare cases faulty

  • cell division may leave an extra X chromosome in one of the gametes that produced the male

  • cat. That extra X then is reproduced in each of his cells, a condition referred to as XXY.

  • Such a combination of chromosomes could produce tortoiseshell or calico markings in the male,

  • in the same way as XX chromosomes produce them in the female.

  • All but about one in three thousand of the rare calico or tortoiseshell male cats are

  • sterile because of the chromosome abnormality, and breeders reject any exceptions for stud

  • purposes because they generally are of poor physical quality and fertility. In any event,

  • an fertile XXY male could not normally pass on any of those X chromosomes to any male

  • offspring, so his male kittens would practically always be normally coloured, either ginger

  • or non-ginger, but not tortoiseshell or calico. As Sue Hubble stated in her book Shrinking

  • the Cat: Genetic Engineering before We Knew about Genes,

  • "The mutation that gives male cats a ginger-colored coat and females ginger, tortoiseshell, or

  • calico coats produced a particularly telling map. The orange mutant gene is found only

  • on the X, or female, chromosome. As with humans, female cats have paired sex chromosomes, XX,

  • and male cats have XY sex chromosomes. The female cat, therefore, can have the orange

  • mutant gene on one X chromosome and the gene for a black coat on the other. The piebald

  • gene is on a different chromosome. If expressed, this gene codes for white, or no color, and

  • is dominant over the alleles that code for a certain color, making the white spots on

  • calico cats. If that is the case, those several genes will be expressed in a blotchy coat

  • of the tortoiseshell or calico kind. But the male, with his single X chromosome, has only

  • one of that particular coat-color gene: he can be not-ginger or he can be ginger, but

  • unless he has a chromosomal abnormality he cannot be a calico cat."

  • It is currently impossible to reproduce the fur patterns of calico cats by cloning. "This

  • is due to an effect called x-linked inactivation which involves the random inactivation of

  • one of the X chromosomes. Since all female mammals have two X chromosomes, one might

  • wonder if this phenomenon could have a more widespread impact on cloning in the future."

  • Calico cats may have already provided findings relating to physiological differences between

  • male and female mammals. This insight may be one day broadened to the fields of psychology,

  • psychiatry, sociology, biology and medicine as more information becomes available regarding

  • the complete effect of random X-inactivation in female mammals.

  • Folklore Cats of this coloration are believed to bring

  • good luck in the folklore of many cultures. In the United States, these are sometimes

  • referred to as money cats. The Japanese Maneki Neko figurine is almost always a calico cat.

  • A cat of the calico coloration is also the state cat of Maryland in the United States.

  • See also Bicolor cat

  • Point coloration Tabby cat

  • Maltese cat Deaf white cat

  • Cat coat genetics Tortoiseshell cat

  • The Cat Who Went to Heaven References

Calico cats are domestic cats with a spotted or parti-colored coat that is predominantly

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Calico cat

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    VoiceTube posted on 2016/01/17
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