So little Ginger had two pretty little orange kittens—and a third who's solid white? How could that be, you might wonder. Cat genetics for color can produce some interesting and unexpected outcomes, and white cats are produced in several ways.
The Dominant White Gene
This gene (W) overrides all other genes for color and produces a white cat. Because of this, the W gene is known as a masking gene. If it’s present, the cat will be white, no matter what the other genes for coat and color say. So a white kitten with an orange mom could have inherited this gene from a white dad.
The Spotting Gene
Cats with white spots are very common. White spotting is produced by an incomplete dominant spotting gene (S) that is affected by other genes and usually produces cats that are only partially white. The degree of spotting varies tremendously, from coats with just a tiny spot of white on the chest to tuxedo coats and everything in between. In some cases, it even produces coats that are just one huge white spot, resulting in an all-white cat. So a white kitten with an orange mother could have inherited the S gene from her dad.
The Albino Gene
Although the term "albino" is associated with whiteness, in cats the situation is a bit more complex—like everything else with them. The albino gene controls the amount of pigment produced by cells called melanocytes. The kitten must inherit two copies of the albino gene—one from Mom and one from Dad—in order to be born albino. That's because this gene is recessive. These cats will have a translucent white coat and pink or blue to gray eyes, and like most albino animals (including humans) will be sensitive to light. True albino cats are very rare, though the parents don't have to be albino themselves; they just have to carry the gene responsible for albinism.
Deafness in White Cats
Deafness in white cats is associated with the dominant white gene and the white spotting gene, but not with the albino gene. Blue-eyed white cats are more likely to be deaf than green- or gold-eyed white cats. This is because deafness in white, blue-eyed cats is caused by the absence of a cell layer in the inner ear that comes from the same stem cells as pigments, which are suppressed in dominant white and white spotting. Some cats have only one blue eye, and these can be deaf on the blue-eyed side. But not all blue-eyed whites will be deaf, since several different genes are at play in determining coat and eye color.
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