08/07/2025
Feline genetics
Did you ever wonder why orange cats are almost always males, or calico cats are almost always females?
Cat genetics are an interesting topic. Feline coat color and s*x genetics are closely related. Cats inherit half of their genetic make-up from their mothers and the other half from their fathers. In mammals, normally females have XX chromosomes and males have XY. Some genes that contribute to color are linked to X chromosomes, making them s*x-linked genes. Genes can be dominant or recessive. All cats originate from two colors: orange and black. So here goes…..
During creation, the dominant gene wins and decides the color of the kitten. The recessive gene loses. But there are some exceptions to the norm. There is another gene that is recessive, the dilute gene (d), which lightens a color. This gene turns Orange to cream/buff, black turns to gray/blue, chocolate turns to lilac/lavender, and cinnamon turns to fawn/light lilac. If a cat is dilute, they may also carry a dilute modifier gene (Dm), which is dominant, and makes their dilute color even lighter: cream/Buff turns to apricot, gray/blue turns to blue-based caramel, lilac/lavender turns to lilac-based taupe, and fawn/light lilac turns to fawn-based caramel. The orange color gene is only carried on the X chromosome. This makes 80% of ginger cats male. If a male is a tortoiseshell or calico, it means he has an extra X chromosome. A cat will have white spotting if they inherit the white spotting gene (S) from at least one parent. How it works: 2 recessive genes (ss) – No white spotting. 1 recessive and 1 dominant gene (Ss) = white spotting on areas like feet, nose, chest, and tummy. 2 dominant genes (SS) = white spotting will cover more than half the body. There is a small chance cat will be completely white!
Confusing? You bet. And we haven’t even gotten into those striped pattern genes!! Good thing nature knows what it is doing. What is your favorite color cat? What would you do if you had a male calico cat? We love all color cats and kittens and are amazed when we see an oddity come into the hospital, such as an orange female cat.