Cat Genetics Part 1 - Basic Colors

The primary pigment in the fur of common house cats is eumelanin, also known as the "black" pigment, though that is a little oversimplified, and it's only called that to distinguish it from phomelanin, or "red" pigment, which I'll cover in a different post.

Eumelanin comes in three distinct colors: Black (B), Chocolate (b), and Cinnamon (bl). Black is exactly what it sounds like, and is a pure black pigment. Chocolate is a plain but rich dark brown color. And Cinnamon is reddish brown and resembles, well, cinnamon.

Examples (all images found on google):

Black -

Chocolate -

Cinnamon -

Black is the dominant allele, so it is the most common color. So common, in fact, that most people have never even seen a chocolate or cinnamon cat. Which is a shame, because they're beautiful.

Chocolate is one rung down, recessive to black but dominant over cinnamon. Let's show a very simple punnet square:

In this scenario, we have two black parents, but they both carry an allele for chocolate. Therefore there is a 25% chance that a kitten will be chocolate instead of black (remember, it's a 25% chance for EACH KITTEN, not that 25% of the kittens will be chocolate).

Cinnamon is the ultimate recessive, and you need two cinnamon alleles to get a cinnamon kitten. Here's a slightly more complicated punnet square:

In this scenario, we have a black parent and a chocolate parent, but they both carry cinnamon.

Therefore, there is a 50% chance a kitten will be black, a 25% chance of chocolate, and a 25% chance of cinnamon.

That's all for this post! I'll cover the Dilute gene next.