 |
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| Gene L:
Shorthair |
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SHORTHAIR gene L
Gene L is responsible that the hairs are short.
Gene L is dominant over its companion gene l, that means shorthair is dominant over
longhair. Gene L must be present only once that the coat of the cat is short. |
Longhair gene l
Gene l is recessive to gene L. If a cat carries gene l double (ll) then its coat is
long. |
Gene combinations
| LL |
homozygous shorthair
|
| Ll |
heterozygous shorthair
|
| ll |
homozygous longhair
|
|
How can this theoretical knowledge be used for the breeding practice ?
You want to breed Exotic
Example 1
You know, that for breeding Exotic always Persians are used to get a good coat texture. But
you do not know if your Exotic is homozygous for shorthair.
We assume we have an Exotic female: L-
We do not know if our Exotic female is heterozygous for L (Ll) or homozygous (LL).
We use a Persian as male: ll
| Case 1: Our female is heterozygous for shorthair:
Ll |
| |
male |
| l |
l |
| female |
L |
Ll
Exotic heterozygous for shorthair |
Ll
Exotic heterozygous for shorthair |
| l |
ll
Persian homozygous for longhair |
ll
Persian homozygous for longhair |
|
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 offspring of a mating between Exotic and
Persian or between Exotic and Exotic - see the following Example - are called Longhair
Exotic and do not 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 Persians like all the other Persians.
|
| Case 2: Our female is homozygous for shorthair:
LL |
| |
male |
| l |
l |
| female |
L |
Ll
Exotic heterozygous for shorthair |
Ll
Exotic heterozygous for shorthair |
| L |
Ll
Exotic heterozygous for shorthair |
Ll
Exotic heterozygous for shorthair |
|
| All kittens we got are Exotic, but all are heterozygous for shorthair, all carry the
longhair gene l. |
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
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 do not know if they are homozygous for shorthair (LL) or
heterozygous (Ll).
Case 1:
Both the female and the male are heterozygous for shorthair:
Ll |
| |
male |
| L |
l |
| female |
L |
LL
Exotic homozygous for shorthair |
Ll
Exotic heterozygous for shorthair |
| l |
Ll
Exotic heterozygous for shorthair |
ll
Persian homozygous for longhair |
|
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 do not carry longhair.
The crucial thing is we cannot 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 expect to get also longhair kittens (Persians). |
Case 2:
One of the Exotic is heterozygous for shorthair: Ll
The other Exotic is homozygous for shorthair: LL |
| |
male |
| L |
l |
| female |
L |
LL
Exotic homozygous for shorthair |
Ll
Exotic heterozygous for shorthair |
| L |
LL
Exotic homozygous for shorthair |
Ll
Exotic heterozygous for shorthair |
|
| It does not matter which Exotic is heterozygous or homozygous, whether the male or the female.
We assume the female is the homozygous one. |
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. |
This example - of course - also works with Siamese and Balinese or with Orientals and
Javanese.
You breed British Shorthair
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 will 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 a very attractive cat.
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[A] [B] [C] [cb & cs] [D] [I] [L] [Mc] [O] [S] [W] [XY] |
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