Tortoise Shell

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Tortoise shell (dress chat)
The dress "tortoise shell" in cats is produced by the particular combination of genetic traits. It is a mixture of red (more or less intense) and black (producing black shades ranging from deep chocolate, cinnamon). The dress has obtained stains red and black, chocolate or cinnamon. The size of the spots varies from very fine planting in large areas of color.

The dilution genes can alter the tone, until the lightening cream mixtures and "blue" (gray), lilac or beige. Sometimes the reasons "tabby" gray / blue can appear (then called these cats "torbie" for "wrong" + "tabby"). The tortoise shell can also occur in the grounds' points' (eg in the Siamese). The name "tortoise shell" is reserved for cats free of white spots while those with broad white beaches and decorated with red spots and dark spots are called "light" or "Calicos (USA). The tortoise shells are not a breed of cat, these colors can be found in animals of different breeds.

The color of the dress cats result of complex genetic influences. One of the genes would be computed has two alleles: the allele Orange (O) which is the dominant form (XO) and that produces a red fur, and the gene Black (o) is recessive form (XO) and which black fur. To be light, a cat must simultaneously express both alleles, O and O, the two versions of the same gene, located in the same location of chromosome X. Males can not accomplish this they have only one X chromosome and thus one allele. As a result, over 90% of lights or scales are females. Very exceptionally light a male born suffering from Klinefelter syndrome, it has at a supernumerary X chromosome (XXY). This is overwhelmingly male sterile.

Finally, the arrangement of colors, and in particular spots of fur, does not of course varies with the time on the same chat.

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