BICOLOUR GENETICS
SIMPLIFIED
Ragdoll genetics are very interesting, and the Bi-colour in particular. If you mate a Bi-colour to a Colourpointed Ragdoll, you should expect to produce 50% Bi-colour and 50% Colourpointed offspring, averaged over 4 litters.
Now for the interesting part and what you need to be aware of when doing your research if you should be intending to buy a Bi-colour kitten to breed with at some stage in the future or use one at stud. There are 4 different genotypes of Bi-colour Ragdolls, three of them having a similar phenotype and the fourth, a High White Bi-colour which often resembles a Van pattern.
The majority of the original Bi-colours imported into the UK in 1981 from the Blossom-Time lines, were what most breeders generally refer to as 'true' or heterozygous Bi-colours, in other words they have only received the white spotting gene from one parent and are able to reproduce their own pattern when mated to a Colourpointed Ragdoll. (i.e. such litters should produce on average 50% Colourpointeds, 50% Bi-colours).
However, we have learned through experience that when you breed Mitted to Mitted, a mating which can produce all three patterns of Ragdolls, the
Bi-colour from this mating breeds totally differently to the heterozygous
Bi-colour, as when mated back to a Colourpointed Ragdoll, they will produce entire litters of Mitted kittens (100%). These Bi-colours are known as 'High Mitted' Bi-colours and are homozygous, having received the white spotting gene from both parents. They are very useful if a breeder wishes to specialise in breeding Mitted Ragdolls.
If you mate a heterozygous Bi-colour to a Mitted Ragdoll, again this mating can produce all three patterns of Ragdolls in the ratio of: 25% Bi-colour, 25% Mitted, 25% Colourpointed, but it can also produce a Bi-colour that we refer to as a Mid High White Bi-colour (25%). The only way to distinguish whether a Bi-colour from a Bi-colour to Mitted mating is heterozygous or homozygous is by mating it back to a Colourpointed. If it is a heterozygous Bi-colour it should average 50% Bi-colour and 50% Colourpointed kittens in the litter, whereas if it is a homozygous Mid High White Bi-colour it will produce 50% Bi-colour and 50% Mitted kittens, no Colourpointeds.
And finally, when mating two heterozygous Bi-colours together, this mating could produce 50% heterozygous Bi-colours, 25% Colourpointeds and 25% High White Bi-colours (the Van pattern). The High White Bi-colours, which are homozygous, are interesting, as when mated back to a Colourpointed they will produce entire litters of heterozygous Bi-colour kittens (100%).
NB: The percentages quoted are an average usually produced over a minimum of four litters.
It is essential that new and novice breeders use a Colourpointed as one parent as this is the way to ensure that you are absolutely certain of the pattern of the kittens that are produced in a litter.
Please do not be tempted to put Bi Colour to Mitted, Bi Colour to Bi Colour or Mitted to Mitted until you are confident enough to be able to distinquish between the patterns you may produce. Even an experienced breeder can have trouble telling the difference between a Mid High White, High Mitted and a Heterozygous Bi Colour!!!
We have included Pattern Charts on the web site, which summarises the patterns that can be produced from the various matings:
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