The Burmese Mutation : cb
The next coat color mutation, found in Thailand, is the Burmese mutation. It is indicated by the abbreviation cb. In the basic black cat, we saw the following genetic formula;
aa BB CC DD
With this mutation, we are going to replace the CC with cbcb. And, to that basic change, you can add all the other Thai coat color mutations.
bb cscs dd
aa Bb Ccb dd
bb cbcs DD
BB cscs dd
The Tonkinese Mutation: cbcs
The Tonkinese mutation is a great example of the real cats of Thailand. Lets start with the standard black cat, aa BB CC DD. In this case, we are going to swap out the big C's and insert one Burmese gene(cb) and one Siamese gene(cs). I say this really represent Thai cats because in reality most of them inherit a mixture of traits and in this case, one Siamese gene from one parent and one Burmese gene from another parent. Add to this mixed gene cat, the other color mutations you find in Thailand.
bb cscs DD
aa bb CC dd
BB cbcs DD
So on the left you have a black cat. On the right, you have a black cat to which two dilute genes have been added. Now you have a blue cat.
Their Babies from left to right
aa bb CC dd = Lilac
aa bb Ccb dd=Lilac
aa bb Ccb dd=Lilac
aa BB Ccb dd =Korat
aa bb cbcb dd
Now to Make Things a Little More Challenging
What I have presented is a simplified version of coat color genetics. In fact, its a bit more complicated than this. And, its worth squeezing your brain to work through this complexity for reasons I will explain a little bit later. But first, let's get complicated.
I will use the Korat as an example. If you test 12 Korats in Thailand you will find that they do not all have the same genetic formula. I presented Korat's as having the genetic formula aa BB CC dd. And, that is most assuredly the formula for one Korat you would find walking on the streets of Thailand. However, because of dominance of some of these genes, you can have a Korat and have genes that are recessive to those genes lurking in the background.
So, in fact, if you test a Thai Korat, you will find their genetic tests reveal following results.
aa BB CC dd
aa Bb CC dd
aa Bb Ccb dd
aa Bb Ccs dd
The big letter blocks out the effect of the little letter, and, with al four of these cats, what you would see is a Korat. And they are indistinguishable. So, the real formula for a Korat is:
aa Bx Cx dd.
A Korat in Thailand can be carrying the recessive chocolate gene, the recessive Siamese gene, and the recessive Burmese gene. Korats in Thailand are very genetically diverse, though they may appear the same physically. Because they carry these recessive genes, depending on who they mate with, these recessives can result in kittens that do not look like Korats.
Here is an example.
aa Bb CC dd
In Thailand, long ago, black cats began to develop adaptive mutations, mutations that made it easier for them to survive in Thailand. Thailand is very very hot and to wear a black, heat absorbing coat around, was a little less than convenient. Over thousands of years, albinistic mutations developed in these black cats that lightened their coat color and made it easier for the cats to survive the heat. They are called albinistic mutations(as in albino) because they involve a loss of color. These mutations result in genetically black cats loosing some of their black color. The end result is genetically black that do not appear black. These albinistic mutations can make slight alterations to the black coat, or significant alterations to the black coat.
Ok, let's dive into Thai cat color genetics a little deeper! Brace yourself for a little science. When you have a Thai black cat tested genetically, the lab sends you back results that looks something like this. Its a formula.
aa BB CC DD
This group of letters is tells you what color mutations the cat carries and is essentially a recipe. Each of those letters are an ingredient, and when you add them all together, you end up with a very different looking cat.
Thailand is home to a collection of unique mutations that add up to the beautiful cats the world has come to love. The primary mutations you find in Thai cats have names and abbreviations for those names. Here is your basic "ingredient list" which will add up to the different cats you find in Thailand.
a = non-agouti
b= champagne or chocolate gene
C= full color
cs= siamese pattern
cb= burmese pattern
d= dilute gene
aa BB cbcb dd
Seal Point Siamese
BB cscs DD
As you will see, depending on which of the ingredients you add to the cats genetics, you end up with a cat that has a really different appearance.
So, lets start with your basic black cat and add these albinistic mutations to them. You will see how the cat goes from black to colors that are most assuredly not black in appearance.
The Thai Black Cat
aa BB CC
aa BB CC dd
bb cbcs dd
What I have learned testing Thai cats is this. They are extremely genetically diverse. When I say this, most people think I mean they are not the products of inbreeding. And that is true. Inbreeding is rarely practiced in Thailand. But they are genetically diverse on a whole different level. A Korat in Thailand can be any one of four different genetic coat color combinations. They carry the right genes to appear like a Korat, but, they carry a whole bunch of other recessive coat color genes hidden behind that blue coat.
It is my theory, very much unproven, that the reason Thai cats are healthy in Thailand, and they are not healthy in the west, is because in the west, all of coat color genetic diversity was bred out of the imported cats from Thailand. The early Korat breeders weeded out anything that was not born Korat. Eventually, all the recessive genes were removed from the western Korat population, through selective breeding. And presto. Korats suddenly developed a chronic degenerative neurological condition. A condition not found in Thailand. Found only in the west where all recessive genes were bred out of the cats.
If I had time I could list other Thai breeds that have had their coat color genetic diversity bred out of them in the west, and the health conditions that seem to pop up at just about the time the "breed" has been cleansed of coat color genetic diversity.
Suffice it to say, Thai cats, in Thailand, have a whole lot of coat color genetic diversity lurking behind what you can see. They do not suffer the degenerative conditions they do in the west, so, to be on the safe side, I am going to go with Thai breeding program. And that would be to embrace coat color genetic diversity.
The Siamese Mutation: cs
Lets start with the basic black cat genetic formula, aa BB CC DD. With the Siamese mutation, we are going to change out the big two big C's with cscs. Still a basic black cat, but, we are replacing the full color gene with the Siamese gene. See how it changes the cats. And, just like with the other cats we have seen, you can then lay the other Thai coat color mutations on top of that and get even more coat colors.
One the left we have a black cat, but in this case, the big BB for black cat, has been modified to bb. When you replace BB with bb, you end up with a warm brown cat. This mutation is called chocolate or champagne, depending on what country you are in. But, small bb in this position result in a warm brown coat color. The cat on the right is a really unusual cat. It has inherited two copies of dilute (dd) from its parents and two copies of chocolate from its parents. I say this is an usual cat because the cat has inherited two copies of three mutations from its parents, aa, bb, and dd. Statistically, all those mutations coming together at the same time is highly unlikely. It happens, but not very often. You won't see many Lilacs in Thailand.
aa bb CC DD
Genetics of Thai Cats
The cats from Thailand, be they Siamese, Tonkinese, or Burmese, all share common coat color mutations that popped up in Thailand long ago. To the uniformed eye, these breeds may look very different physically, but, genetically, they have more in common than you might think. The topic of Thai cat genetics, in my opinion, is totally fascinating. While working with Thai cats, I have learned a lot about Thai cat genetics, and, decided to provide that information here. There may be a limited number of people who share my interest, but for those of you who do, here are some details behind the magical coat colors that come from Thailand.
Welcome to Genetics of Thai Cats
The jumping off point with Thai cat coat color genetics is with a mutation away from the wild stripey cat, and to the not stripey solid black cat. All the Thai cats you know, spring from this mutation branch of the cat family. Please see your basic Thai black cat. In fact, please see two basic Thai black cats.
aa BB cbcb DD
aa bb cbcb DD
BB cbcs dd
Dr. Douglas Schar and Dr. Anatoly Vinokur