Gene L, l |
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SHORTHAIR gene LGene L is responsible that the hairs are short. |
Longhair gene lGene l is recessive to gene L. If a cat carries gene l double (ll) then its coat is
long. |
Gene combinations
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Example 1
You know that for breeding Exotic always Persians are used to get a good coat texture. But
you don't know if your Exotic is homozygous for shorthair.
We assume we have an Exotic female: L-
We don't know if our Exoitc female is heterozygous for L (Ll) or homozygous (LL).
As male we use a Persian: ll
| Case 1: Our female is heterozygous for shorthair: Ll |
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We have got Exotic and Persian with the ratio 1:1, but note that all Exotic are heterozygous for shorthair, all Exotic carry longhair. In some federations, f.e. in CFA, the longhair offsprings of a mating between Exotic and Persian or between Exotic and Exotic - see the following Example - are called Longhair Exotic and don't have championship status. In other federations, f.e. in FIFe where the standard of Exotic and Persian is completely the same except the length of the hair, those longhair kittens are taken as Persian like all the other Persian. |
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| Case 2: Our female is homozygous for shorthair: LL |
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All kittens we got are Exotic, but all are heterozygous for shorthair, all carry the longhair gene l. |
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This example also works for Siamese and Balinese or for Orientals and Javanese. If you
cross Siamese with Balinese you get both the Siamese and the Balinese, the same is with
the Orientals and Javanese.
In some federations the shorthair kittens resulting from a mating between a shorthair cat
and a longhair cat are called variants.
Example 2
We want to mate two Exotic but we don't know if they are homozygous for shorthair (LL) or
heterozygous (Ll).
| Case 1: Both the female and the male are heterozygous for shorthair: Ll |
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| We have got Exotic and Persian with the ratio 3:1, but note that 50% of
our kittens are heterozygous for shorthair, they carry longhair. Only 25% of our kittens
are homozygous for shorthair, they don't carry longhair. The crucial thing is we can't see from the phenotype which of the Exotic is the homozygous one and which are the heterozygous ones. We also got Persians out of this crossing. Conclusion is: If you cross two Exotic which are heterozygous for shorthair you must exspect to get also longhair kittens (Persians). |
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| Case 2: One of the Exotic is heterozygous for shorthair: Ll The other Exotic is homozygous for shorthair: LL It does not matter which one is heterozygous or homozygous, wether the male or the female. We assume the female is the homozygous one. |
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| All kittens we got are Exotic, and already 50% of the Exotic are
homozygous for shorthair. That is a breeding technique how to increase the level of homozygosity. |
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This example - of course - also works with Siamese and Balinese or with Orientals and
Javanese.
You wonder that you got longhair kittens in your litter although both parents had been
shorthair. How could this happen ?
Remember our examples above, when you look at example 2 case 1 you will know why you got
longhaired British Shorthair.
If you have in your litter a longhaired British Shorthair you know immediately : both the
male and the female must be heterozygous for shorthair (Ll), that means they both carry
longhair (l).
When you look into the pedigrees of those cats you'll mostly find one single Persian in
one of the last generations, 4th or 5th generation. A gene can be carried on through
generations until you might see its effect.
As it is not desirable in British Shorthair to get longhair kittens. You should think
about to use another male.
When the Colourpoint British Shorthair had been bred mostly Colourpoint Exotic had been
used, with the consequence that the longhair gene l was introduced into the British
Shorthair and will remain here for a while. But by the way the Colourpoint British
Shorthair is quite an attractive cat.
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Last modified on 99-01-16