British Shorthair Colours

British Shorthair coat colours – how parents pass colour on to their kittens

British Shorthair cats come in an exceptionally wide range of coat colours – from classic blue, black and chocolate, through lilac, red and cream, to tortoiseshell, silver, golden, tabby and colourpoint varieties. A kitten’s appearance, however, is not a matter of chance. Coat colour and pattern are the result of genes inherited from both parents.

Basic colours
Most coat colours are based on either black or red. Other colours can arise through the action of additional genes. For example, the dilution gene causes:

• black to become blue,
• chocolate to become lilac,
• red to become cream.

The dilution gene is recessive. This means that a kitten must inherit the relevant gene variant from both its mother and its father for dilution to be visible. A cat may therefore appear black while still carrying the dilution gene and passing it on to its offspring.

Why can female cats be tortoiseshell?
The inheritance of red colour is particularly interesting because the gene responsible for it is located on the X chromosome.

A male cat has one X chromosome, so in principle he can be either red or non-red. A female has two X chromosomes and may inherit the red-colour gene from only one of her parents. This results in the characteristic tortoiseshell pattern, combining red areas with black or – in the diluted version – cream with blue.

For this reason, the colours of the parents allow breeders to predict some of the possible coat colours of future kittens and, in certain matings, to associate particular colours with the sex of the offspring.

Colour is only the beginning
Many more genes influence a cat’s final appearance. They determine, among other things, whether tabby patterning, silver, gold, white markings or colourpoint colouring will occur. Some traits may remain hidden for many generations and only become visible when a kitten inherits the appropriate combination of genes from both parents.

This is why knowing not only the parents’ coat colours but also their pedigrees and genotypes allows a breeder to predict the colours of future kittens much more accurately.

At Gotham Cattery, analysing the inheritance of coat colours is one of the elements of thoughtful breeding planning – alongside health, temperament, breed type and genetic diversity.