The following table shows the outcome of matings with regards to the patterns.

Bicolour

The Bicolour gene is still a mystery to the genetic society. It seems like there are at least two differnet genes giving white and selfs. One gives Bi-Colour, Harlequin or Van and another giving the medalions that are so classical in some breeds and the moggie. Since only the first gene is allowed in the BSH breed it is impossible to show or register a BSH as 09 This is also the reason why there have to be at least 1/3 white, it is so that there won´t be a mix-up.

The medalion gene is recessive so it has to be present at both parents. There are som indications that there might as well be a separate gene for the Van pattern, maybe working together with the Bicolour gene to give Vans.

Inheritance of Bicolour (excluding the medalion)

The Hetro-Bicolour cat is hetrozygotic for Bicolour, thus carrying one self and one bicolour gene. The Homo-Bicolour cat only carries genes for the Bicolour and can thus never give rise to self coloured cats.

There is nothing stating how much white there will be in a mating between two bicolours, but there are empirical support for the statement that parents with little white gives offsprings with little white. Information from american breeders show  an inheritance of the placement of the patterns as well.

The tabbygene

The silvergene

Colourpoint

British Shorthairs that are masked or colourpoints is a fairly new pattern, brought in by matings with Himalayan persians. The masking is a recessive gene and is inherited as follows:

A carrier is a cat that carries the gene for colourpoint. These cats often are presented with the figures 33 within paranteses behind the EMS-code, f.x. BRI c(33) for a lilac brit that carries the colourpoint gene.

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