Cat Coat Genetics 101—Explaining the Essentials
By Ashley Bates
Cat genetics are combined in all sorts of crazy ways to create lovely coat colors of various shades and patterns. Breeders closely analyze these color patterns to create desirable colors in the breed. Particular outcomes are possible, permitting the genes mix just right.
But what exactly determines how the parent genetics will impact each kitten? Here, we will go over the basics of all you need to know about cat coat color.
Cat Coat Genetics: General Info
As you may guess, genetics is a pretty extensive topic. We need to be clear that this is meant to be a general guideline, not a complete guide on genetics. If you need more in-depth information about cat genetics, absolutely turn to professionally written books that delve into the science.
Chromosomes are defined as a threadlike structure of nucleic acids and protein found in the nucleus of most living cells, carrying genetic information in the forming of genes.
Each chromosome is made up of a protein and singular molecule DNA. When passed to the offspring, it contains a code that makes each kitten unique. X and Y chromosomes are what determine the gender of each kitten. Females have XX chromosomes while males have XY chromosomes.
Kittens inherit half of their genetic makeup from each parent, which equals 19 chromosomes in each, totaling 38.
All life has a genetic makeup of bases. There are only four: A, C, G, and T. These tiny particles in genetics build in small strands to make up the DNA genome, containing all biological information about each living thing.
When genes combine, there are two main types:
- Allele Genes: Allele genes are the same genes with small differences in the DNA code.
- Recessive Genes: Recessive genes are genes that become masked by dominant genes.
- Dominant Genes: Dominant genes are those that show up most often in offspring.
An Example About Genetics
An example of how genetics play into our existence goes a little something like this.
We have a mother and father cat. For this example, let’s say one is black and the other is white—and no other color exists in either genome, to keep it simple.
When the two breeds and a successful pregnancy occurs, this means half of the mother’s genetics and half of the father’s genetics pass to each kitten in the litter. The parents will carry both recessive and dominant traits.
Depending on how the genetics line up, you would either get a black cat or a white cat—and only the immediate parents determine the color and pattern for the kittens.
How Genes Come Together
All cats originate from two colors: orange and black. That’s pretty phenomenal, considering how many coat colors exist today. You’ve probably seen a female with a litter of kittens—and none of them look like her. They’re all sorts of patterns and colors, but not hers. Have you ever wondered why?
There is a coat color and pattern to consider when it comes to appearance.
The orange gene is simply orange O. The black gene is B. However, black has recessive variations, including chocolate, cinnamon, and dilute.
Another interesting fact is related to gender. Orange is much more common in male cats than females. A whopping 80% of all orange cats are male. Why?
Females need to have an orange gene from both parents on the X chromosome, which tells them to take the orange color.
That means females need two X chromosomes and males need only one.
|Gene Name||Symbols||Function||Wild Type|
|Agouti||A, a||Non-agouti cats (aa) are solid, tabby is difficult to identify||A|
|Amber||E, e||Gradual replacement of eumelanin with pheomelanin||E|
|Brown||B, b, b1||Brown variants have reduced eumelanin, including colors chocolate and cinnamon||B|
|Colorpoint Restriction||C, cb = cs, c||Temperature-sensitive alleles create sepia and points||C|
|Dilution||D, d||Uneven pigment distribution of coat color||D|
|White Gloves||G, N||Birman white gloving pattern||N|
Texture and Length
A gene determines a cat’s coat length called the fibroblast growth factor 5—or FGF5. One is the dominant code for short hair. The other four are mutations for long coats but are all recessive genes.
Curly coats can occur naturally, but some cats are bred to look this way, like the Devon Rex. Some coat genes are called r rex, cr Cornish rex, and la in the LaPerm breed. Interestingly, the rex gene is also possible for other animals like rabbits and rats.
Hairlessness is a trait identified as Hp. It can occur both naturally and through specialized breeding, as with Sphynx or Lykoi cats.
Calicos & Tortoiseshells: Why They Differ
Hearing of a male calico or tortoiseshell cat is nearly unheard of if you didn’t know. It’s so rare that you would probably be rolling in the dough if you ever find one. So, what makes it so impossible for these color patterns to be male?
For the tri-color coat pattern to come through, you need X chromosomes. Two XX chromosomes will always be female, as an XY pairing is always male.
There is only one exception to this rule: XXY syndrome. This occurs when a male has two X chromosomes and one Y—which is only one in every 3,000.
Genetics is something that is studied by scientists all the time. It is by no means a short subject to master. Different combinations can take a long time to master. Plus, with so many aspects playing into the overall coat appearance, it’s a real challenge to retain all the details.
But we really hope that summed it up in Layman’s terms for you. If you have more questions about genetics, we recommend searching for a few books on the subject.
See also: Can a Litter of Kittens Have Multiple Fathers? Superfecundation Explained
Featured Image Credit: Yulia Grigoryeva, Shutterstock