orange tabbies

kelli

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I own a female orange tabby. My vet has just informed me that most orange tabbies are male, and most calicos female. Can anyone explain to me why this is so?
 

fireshoes

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Yes it is rare. I have read that approximately 90% of orange tabbies are male. I found this on a web site.

Red and tortie
Red is a so-called sex-linked color. A female cat has the gene combination xx, whereas a male cat has the gene combination xy. The gene for red (o) can only be carried on the "x" gene. That means a female cat can have two o's, a male cat can have one. The "y" is "unused".
Red cats often show tabby ghost markings, even if they are non-agouti. That's why breeding of red cats is so difficult.
Basically, x means non-red (any other color than red -- cream is red, too, it's just diluted) and xo means red. So a male cat can either be red or non-red, since it only has one x (this is called "hemizygous").
A female cat has two x's that can both be red and non-red. This is how the tortie color is "created". When one of the x's is red and the other one non-red, red and non-red patches will be spread randomly all over the body. This is what we call tortie.
If the tortie cat is also bicolor, the small patches will be formed into clearly contrasting areas of red and non-red. This is also known as "calico".
Actually, male tortie cats do exist, but only if there is an abnormality in the sex-determining genes. This is called "Klinefelter" and extremely rare, so don't expect to get one in one of your litters. If so, he would be no use to you, since such males are always infertile because of the abnormality. The gene combination would be xxy, which means the cat would have three genes instead of two.
 
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