If you were to describe it simply, there are two traits that a cat always, always has and that is:

• Basic Color

• A pattern, Classic, Mackerel, Spotted or Ticked, (it may actually be two or more, but that will be addressed later).

Then we have a whole lot of different genetic predispositions that will affect what the cat will look in the end. But in this section we will only address the basic colors as well as agouti which is the predisposition that decides whether the pattern will be shown or hidden.

By starting from scratch and forgetting about all the other predispositions that might change the color of the cat, it's a lot easier to learn all the different colors, you learn the inheritance from scratch and then build it up bit by bit.

Basic Color

The basic color of a cat is always black or red so a cat always has the predisposition black, red or both in a tortie.

The genetic designations are:

Black = o
Red = O
Blacktortie = Oo

The basic color is sex-linked, which means that it is inherited on the X chromosome. As we know, (if we did not sleep in school), the eggs are always X and the sperm then determine the sex by being X or Y.

XX - Female
XY - Male

As seen above, the males will always get their color from the mother (they only have one X).

The females, on the other hand, get a color from mother and a color from father, hence a female can become a tortie, ie both red and black.

Note that we are now ONLY talking about the basic colors, ie red and black. So if we take the example above with Black and Red, we can see the genetic difference between males and females.

The genetic designations are:

For a female:

Black = oo
Red = OO
Blacktortie = Oo

For a male:

Black = oy (y since the male has XY and thus no color on Y)
Red = Oy

Above therefore applies to all cats whether they are blue, cream, red, black, torties in different variants, with and without silver with and without white, with and without pattern…. these two basic colors are always present in your cat, one of them or maybe both if you have a female.

By: Malin Sundqvist
Dagdrivarn (www.dagdrivarn.se)