Bicolour occurs because there is no dilution gene to mix the colours of the coat to an intermediate shade. In contrast, tabby cats have an agouti gene, producing striping of the coat. The Abyssinian cat has agouti with dilution, giving the appearance of even colour with colour-banded hairs.
A black-and-white bicolour cat is often known as a tuxedo cat or a Jellicle cat.
The Turkish Van cat(white and ginger) is one good example of a bicolour breed.