“They are actually alleles, meaning they are two variations of the same gene in one location on the chromosome,” he says. Jerold Bell, adjunct professor of genetics at Cummings School of Veterinary Medicine at Tufts University in North Grafton, Massachusetts. This is the same chromosome that, along with Y in males, determine a cat’s sex, says Dr. The color genes for black and red in cats are contained within the X chromosome. And red, which is determined by the orange gene, can become cream. These colors can mutate into different shades-black can become chocolate, cinnamon, lilac, blue and fawn. Whether calico, tortoiseshell, orange, black, brown, or gray, a cat’s fur color is derived from two dominant colors: Black and red. A small percentage of orange cats are female, and even a more miniscule portion of calico cats are male.īelow, learn how genetics and sex influences a cat’s coat color, and why some cats don’t fit typical color patterns. Nature doesn’t always abide by a rigid set of rules, however, including when it comes to feline fur color. Thus, no color is associated with a particular sex, except in cats and hamsters.” “Since the genes for sex and hair colors are on different chromosomes, they are inherited independently of each other.

“These other chromosomes contain genes that affect hair color, pattern, shape and length,” Grahn says. Robert Grahn, a forensic analyst at the veterinary genetics laboratory at the University of California in Davis. But a number of additional chromosomes are present and vary depending upon species, says Dr. As you may recall from high school biology, mammals have two chromosomes that determine their sex-XX for females and XY for males. The color of a cat’s coat is closely linked to its gender. Most orange cats are male and most calicos are female.

And you’re certain that the orange tabby you’ve fallen in love with at the shelter is a boy. You’ve always assumed the calico cat that sits in your neighbor’s window is a she.

Tortoiseshell calico