Dominant = Show the effect of the phenotype in the cat, one dominant gene must be present to see this, Bb = Black/Seal carrying brown/chocolate

Recessive = When the effect of the phenotype can not be seen in the cat. When only one gene is present, this same gene must be there twice to show the effect of the phenotype, bb = brown/chocolate.

The "I" (Inhibitor) and "A" (Agouti) are dominant in all colours. The recessive genes can be carried through numerous generations.   Both "A" and "I" are single and dominant. (what you see is what you get)   Keeping in mind that colour is separate from pattern.

All cats have an agouti pattern "A", visible or not. The "A" brings the bands to the fore, and the yellow, fawn, brown under lying colour. It is the most natural occuring gene going back to nature.

The "A" Agouti gene shows cats in patterns, as Tipped (Abyssinian), Classic (blotched, bulls eye patterns), and Mackerel, (fine tiger bands) and even spots. Introducing a solid colour to agouti can create solids and agouti. Agouti to agouti can also create solids and agouti.

Introducing the Inhibitor gene "I" with the "A" gene will turn the yellow underlaying colour to white/silver, and the shafts of the hair upwards white/silver, hence the banding comes to the fore giving you the silver tabby. The "I" gene with the cat that is not agouti "A" will be a Smoke.

The inhibitor gene, "I", simply 'inhibits' the production of colour on the hair shaft. As a result part of the lower end of the shaft is devoid of colour and appears white or 'silver'.

How you will see the silver is determined by the polygenic activity. Polygenes control the depth of tipping on the hair, varying from 1/4" to 1/2" down the hair shaft, the length of the hair and density.

Due to selective breeding the polygenes can be governed and the results will be foreseen. Polygenes therefore determine how dense the colour appears to the human eye. The more silver, the less tipping of colour present in the hair shaft, the lighter the remaining colour will seem.

 Continually breeding silvers to silvers and keeping the gene pool closed in, an already small gene pool, can be considered undesirable and would not help to improve the type. It is imperative to introduce solids with silvers, to prevent inbreeding, and to improve type. 

 

Tarnishing is incomplete clearing of the yellow pigment of the hair shaft. Resulting in a dirty or tarnished silver which is a fault in a silver cat. Shading can occur in all the colours of the Birmans for many different reasons and is completetly different from tarnishing.

Some silver kittens born, with more tipping (pigment) on the hair, can be mistaken for solid colours, even though they are "low grade silvers". Unless they are used for the silver breeding programme, they should be sold as pets. As a result of silver to silver matings and non silver to silver, in our breeding programme, we have silver and non silver from both.

To be a breeder of silvers you have to be clear in your decisions and have no doubts of what the colours are, and registering them as such. To be able to accept advice from other breeders that have/have had silver breeding programmes, and to have a open mind. To focus on the high grade silver, and the type as per the standard, is a very exciting and different challenge.

The dual registration for the silver breeding programmes, ie: Blue Silver Tabby = 52 s/FA, Blue Tabby pt = 52 FA(s) is recommended to prevent any argument for breeders not wanting silver in their lines in the future.

In my opinion nothing could be more beautiful than a Silver Birman that sparkles inside and out. Grand Champion Kyat Fancypaws Polar Bear

Sandy Steward, Noelene Dally, Pauline van der Hoorn.
Fancypawz Birmans