C-gene

This gene controles the amount of pigmentation in the cat

C is the full colour (black, chocolate or cinnamon)
c_b is the burmese
c_s is the pointed cat
c_a is the blue eyed albino (ressive white)
c is the redeyed albino

The C gene dominates all the others
c_b partly dominates c_s (the combination [c_bc_s] is the tonkanese which has pigmentation les than a burmes but more than a pointed cat)
It is unknown weather there are any other partly dominance between the others.

There is only combination between C and c_s in the same breed (Siamese/Oriental Pearian and Colourpoint Persians and British Shorthair and Colourpoint British and some of the Rex cats.