Post by LaurelTree on Sept 28, 2016 17:03:50 GMT -5
Basic Cat Color Genetics
I'd first like to start out by clarifying that what most people believe are breeds are actually very common and recessive markings or patterns.
Tabby/Tabby-cat: This is not a breed. I've seen many people state that their cat or cat character was a Tabby by breed. It is, in fact, a markings pattern. This marking pattern happens to be in every cat, whether you see it or not. Even cats that are spotted or splotched. This includes solids, calicos, tortoiseshells, and albinos.
Calico/Tortoiseshell: This, too, is not a breed. It's a color pattern that occurs in female cats and, rarely, in male cats. (To be explained further.)
Siamese/Seal-point: Siamese is a breed while seal-point is a genetic defect that messes with the colors of a cat. Siamese' have the defect of seal-point living in them. Other cats may carry this defect, but it doesn't just happen. It is something that must be bred for or inherited from a parent with that defect. Something similar is lynx-point; a pointing much like seal-point that is accompanied by faded tabby striping.
Before I can go on, you must understand the two color categories that cat's can come in. Yes, I did say two. There are only two color genes for cats; Black and Red.
From black you get chocolate (brown) and cinnamon (light brown). If you dilute black you get blue (grey). If you dilute chocolate, you get lilac. And if you dilute cinnamon, you get fawn.
Black is the most dense of its color; brown being slightly less than black and light brown being slightly less than brown. You lighten those dense colors to get diluted (even lighter) colors. Brown is recessive to Black. Light brown is recessive to Brown.
Red is harder to get than black. Also, it doesn't come in different levels of density, only dilution. As Red becomes more diluted it gets lighter and lighter. From Red you can get different oranges and creams.
Black is recessive to Red. Meaning that Black can turn into Red. Although, Red cannot turn into black. For example, two black (or any variation of the black chromosome) cats may end up with a red offspring. However, two red (or any variation of the red chromosome) cats may not have a black offspring unless the mother carries an unseen black chromosome from one of her parents (explained more below).
Now, to explain the whole X chromosome concept. I know, that sounds super technical, but to be honest; it's not. I promise.
A color chromosome is like a slot in a living thing's genetic code. For cats, males have only one X chromosome while females have two. A male cat will get its chromosome from it's mother. A female cat will receive one from each parent. This means a male cat can only get its coloring from it's mother or maternal grandparents.
Females are a little different and slightly more complicated. Although, not by much. They, as stated before, get one X chromosome from each parent; mother and father. Grandparents from each side are included. However, because of this duel chromosome pairing, you can get calicos and tortoiseshells.
To explain:
Now, if we keep in mind that females have two X chromosomes and that there are two colors (Red and Black), we can understand this concept very easily.
A female gets a Red chromosome from one parent and a Black chromosome from the other. The Red comes out in an orange coat, while the Black shows through in Dark patches. If she also happens to have white (a coloring not in the chromosomes, just a completely diluted patch of color) that will show on her stomach/underbelly area.
Make sense?
If you understand what all you just read, you'll now see why males do not come in calico or tortoiseshell. Or do they?
Don't let me confuse you; it's true, males only have one X chromosome. However, there is a defect called Klinefelter's syndrome that attacks a male's X chromosome making it develop a 'sub' X chromosome. (Xx) From this, you will very rarely see a male cat with calico or tortoiseshell markings. And, unfortunately due to the defect, the male is usually sterile with other problems occurring in his life. Such as major health issues and an unfairly short life-span if the individual even lives past birth. Mental retardation also occurs in many cases.