Updated: Apr 2, 2021
Just like people, cats also come in a variety of shapes and forms. These different colors are part of the reason cats are so unique and exciting since there are so many choices to pick from.
Have you ever thought how a Red Male and a Black Female could end up with a Gray Male kitten? The answer is genetics, and understanding why cats can differ so much is relatively simple. All you need is a pen and paper and basic high-school level genetics.
At the most simple level, cats only come in two colors: red (meaning orange), and black. What causes all the variations in color are alterations of the cat's genetic code that modify this starting color. Below is a list of common alterations:
This is the most simple color to understand. These cats will have no modifiers to their coat color genetics, so they will appear as one single color. Solid cats may be carriers of other genetic factors that could potentially influence the colors of their kittens. Our breeding stud, Monsieur Fuzz-Fuzz, is a solid red male with several recessive genes that are responsible for the assortment of colors our kittens have.
This is where things start to get tricky. The primary coat color (red and black) of cats is carried on the X-Chromosome, meaning that it is sex-linked. Under normal circumstances, males will only have one X-Chromosome, meaning that they can only carry one gene for primary coat color, being red or black. On the other hand, females will have two X-Chromosomes, meaning that they can carry two genes for coat color.
Therefore, a female can potentially have two red genes, producing a solid red female; two black genes, producing a solid black female; or one red and one black gene, producing a tortoiseshell female.
On a cellular level, all cells will only express one of their X-Chromosomes, never both. This is called X-Chromosome inactivation (Barr Body) and also occurs in people. Which of the X-Chromosomes gets inactivated is determined during gestation and is entirely random. When a cell divides, the very same X-Chromosomes will be inactivated for this cell line. And because tortoiseshell females carry two different genes for color, some cells will express a red gene and others the black gene.
This produces a mosaic pattern, where parts of the cat will be red and others black depending on which X-Chromosome gets shutdown. Males do not do this because they only have one X-Chromosome, though in Klinefelter's Syndrome they can. Klinefelter's Syndrome is when a male will have two X-Chromosomes in addition to their Y-Chromosome, they will have Barr Bodies just like females. These cats are extremely rare and are sterile.
These cats will have normal expression of their primary coat color on their face, ears, paws, and tail, while having minimal expression on the rest of their body. Researches have found that this is because the enzymes that determine coat color can be affected by temperature, though the exact process is not entirely understood. This mutation originally was found primarily on Siamese cats and was eventually bred with a Persian to produce the world's first Himalayan Persian.
The gene causing the color-point is somatic, meaning that it is carried on chromosomes other than the sex-chromosomes (X and Y). It is a recessive gene, meaning that in order for the pattern to be expressed, a cat must carry two of these genes. If a cat only has one gene, they will not have the color-point pattern
So cat with primary red coloration that has two genes for the color-point pattern becomes a flame-point, while a black cat becomes a seal-point.
These cats have a lighter expression of their primary coat color. Just like the color-point pattern, the genes for dilute coloration are both somatic and recessive.
So a cat with primary red coloration that has two genes for dilution becomes a cream, while a black cat becomes blue (Gray).
The Tabby coat pattern determines whether or not a cat will have stripes and in what arrangement. This is the gene that gives cats the characteristic M-Shape on their foreheads.
This gene is also somatic, and all cats will carry this gene. The expression of these gene may be overshadowed by other genes, so some cats will not have any tabby patterns shown. Black cats will very rarely have the tabby pattern while red cats are more likely to have some tabby markings.
There are several types of tabby patterns: Mackeral, Ticked, Spotted.
White cats are different than albinos. Albinos will have absolutely no color expression on their bodies because they lack melanin. White cats express minimal melanin with a reduced survival. Both result in a similar appearance, but for different reasons.
The genes for white coloration are somatic and recessive. These cats are at risk of being born deaf.
These are the standard and most well known coat colors a cat may have. There are several other less common gene mutations possible: hairlessness (Sphinx Cats), shading, silver/golden, recessive genes for primary coat color (chocolate/cinnamon).
Because coat color genes are located on different chromosomes, a cat can have multiple modifiers to their primary coat color. For example, a male cat with red primary coat color and genes for dilution and color-point pattern would result in a cream-point.
Part of our responsibility as breeders is to make predictions as to what colors our kittens will be. The way we do this is using Punnett Squares and use our knowledge of the genetic characteristics of the parents to statistically predict the likelihood of the potential colors their children will be.