The Silver trait is a dominant trait. With dominant means that the cat only needs to have ONE copy of the gene for it to appear. So you if you see it, it’s there, if you do not see it, there is also nothing to inherit.


But most rules got exceptions,  I just want to mention it very briefly and it’s not something we should go deeper into, but it has been proven over the years that the silver sometimes hides, especially on blue cats. The cat appears to be non-silver, but it got the silver gene and inherits it to its offspring.  So there are cats with "invisible" silver, although this is relatively uncommon.

Then we have the purely linguistic that can make it hard for new, a cat with this gene is called different depending on whether it is agouti or non-agouti.

 

Agouti = Black silver tabby, red silver mackerel tabby, blue silver ticked tabby etc….

Non-Agouti = Black smoke, Red smoke, Blue smoke etc ...

In this article, I will talk about the trait itself and will just call it silver.

 

The silver trait is designated I (for the inhibitor gene).

 

 ii

Non-silver

The cat has no silver gene and will not show silver nor inherit any silver.

 Ii 

Heterozygous silver

The cat has one copy of the gene and will be able to give either silver or non-silver to its offspring.

 II

Homozygous silver

No matter what the cat is mated with, all offspring will be silver if the parent is homozygous since it will always inherit one copy of the gene (I).

 

If we do a test mating, one can easily see that two non-silver will never ever be able to get any kittens that are silver, however, two heterozygous silver will be able to get kittens that are non-silver.

 

As can be seen in the table below, where both mom and dad are non-silver, the kids will also be non-silver. Thus, as seen here, there is no I, only i.

Male

i

Male

i

Female

i

ii

ii

Female

i

ii

ii

 

If we take another example then we will see another scenario here, both mother and father are here Silver but both are heterozygous and got 1 set of the silver-trait.

In this example, 50% will be silver but carriers of non-silver. 25% will be homozygous silver and 25% will be non-silver.

Male

I

Male

i

Female

I

II

Ii

Female

i

Ii

ii

 

If we take another last example were let the female be homozygous silver, and then we will see below that all offspring become silver. 50% will be heterozygous and 50% homozygous.

Male

I

Male

i

Female

I

II

Ii

Female

I

II

Ii

 

There is not much more to say about silver genetics when it comes to silver itself. However, silver can be tricky and can have a wide range of expressions, everything from very vague silver to cats with razor-sharp contrasts.

 

Now I will get into a very exciting part but also a very tricky one, and remember that here we are no longer talking about certain facts but only about theories of which there are a lot.

I am talking about the patterns Shaded/Shell, (I will not deal with golden in this section other than very very brief, this will be complicated enough anyway).

 

For many, many years, a theory of an incompletely dominant wideband-gene has been put forward, at least in our neighbourhoods, as the cause of these colours.

Chinchilla (old designation it’s now called shell for all colours)/Shell = WbWb (ems code: 12)

Shaded = Wbwb (ems code: 11)


However, this theory has begun to be questioned by both researchers and breeders.

 

One of our most persistent researchers, regarding the colour-genetics on cats, Leslie Lyons, says that today the wideband gene is suspected to be recessive, so two copies of it are required for the trait to appear. But then we get to the question, IF now the wideband-gene is recessive, then what makes chinchilla/shell? The theories are that we are talking here about polygenes and selective breeding of the brightest cats.

I have recently discovered that this might be wrong, that shaded in the MCO after all actually are dominant, there has been a lot pointing to this when test breeding. It might be that one problem is that so many breeders do not know what shaded are, they do not know what to look for or how to determine that they do have a shaded kitten or are being told completely wrong by the bigger mass of breeders working with shaded today. 
Today it's a lot talk of brightness only, well how bright the cat is, has nothing to do with shaded or not, a shaded should have contrasts, you should be able to put the cat's fur against a paper and clearly see an edge where the silver stops and the "tipping" the colour begins. This is not the case with many shaded today, they are bred to be so pale in the tipping that they are almost white even in those cases where the silver is in fact only 50% of the hair. This is not correct for a shaded cat. In the meanwhile, breeders with shaded cats are told only by a look at the cat, without anyone asking about how the cat does look at the bottom of the fur, without having a look to see if the hair actually are 1/3 tipped and 2/3 white, that the cat is NOT a shaded because it's too dark. Please start looking at the bottom of your silver cat's fur, you might be sitting on a shaded without even knowing about it.
This goes especially for the old shaded lines. Not the Kumskaka Many Water - Belushies Utah - Allycoon Bright Star - Aloa Nifty Wolf-line, those might be shaded but a lot points to this line carrying some completely different gene, but we do not know anything for sure, maybe there are other polygenes in place here, maybe it's complete other genes, without further studies of those cats and without the possibility to do DNA-testing, we just don't know.

Until we have a genetic explanation, we have to settle with the fact that this is something we are only able to have theories about. We simply don't know anything for sure. 

 

One could say that the wideband-gene turns on or off the trait itself, then polygenes play a part in how light the cat gets, whether it falls on the border of normal silver or on the border with Shell or even becomes Shell, it is probably the closest we come to the truth today, without knowing anything for sure.

I have studied these colours a lot lately and I have come to the conclusion that we have many more "shaded" than we think, however, we are most likely to have a lot of "bad" shaded just as we can have bad tabby, spigrés (Swedish nickname for a combination between mackerel tabby and spotted, generally bad pattern with other words) in English it would probably be called Spackerel or something.

 

Many who breed shaded today got, seen with "my" eyes, in fact, cats that are shell, I have been active on many different forums where these colours are discussed and I hear over and over and over the repetition of the words "in my opinion" pronounced. Personally, I prefer standards and some written guidelines, based on previously set rules and if we take a look at these, none of them comments on how light or dark a cat may be to be considered shaded or shell, other than that a Shell should be perceived as much lighter than a Shaded.


The gene code for Shaded/Shell according to the above theory, with recessive wideband-gene is.
A- I- wbwb  (The cat must be agouti, silver and have two copies of the wideband-gene)
or
A- I- Wbwb (If the trait instead are dominant)

 

Then how do I know if I have a shaded? What shall I look for? Some standards are more distinct than others, in the descriptions and express themselves slightly different but you can use below as a first step.


Shaded shall have  ⅓ tipping (colour) and the rest of the hair shall be white.
Shell Shall have ⅛ tipping (colour) and the rest of the hair shall be white.

If you look at the standard when it comes to Shaded, then it is much more to it.
The cat should not have any visible pattern even if it is agouti, it should be brighter on the legs and sides, nor should it have any unbroken rings on the legs. Broken rings are allowed and they shall be perceived as much darker than a Shell.

The coat on the underside of the feet is coloured and on the hind feet, the colour may extend all the way to the joint.

 

When it comes to the Shell it is stricter, no visible pattern allowed, face and legs may be slightly tipped with very light colour. They should be much lighter than a Shaded and the colour of the hindlegs may not extend all the way up to the joint of the hindlegs instead they shall be without any tipping there.

Just to very briefly mention golden, the theory is that a golden shaded is a shaded cat but without silver.

Hence the gene designation is A- ii wbwb, if you follow the above theory of recessive and A- ii Wbwb if the gene is dominant.
These should basically look like a shaded but the bottom shall be beige-yellow-apricot instead of white.


Above is a good guideline to follow.  If you like to read the standard it is a good idea to read through all the standards of the different federations to get a clearer picture of what they say.

 

YankeeCatsAngelOfJoy

Yankeecats Angel of Joy
Blacksilvertortie Shaded (fs 11)
Photo: Britta Singethan

20191223 Horagalles 05 Copy

Dagdrivarn Horagalles
Red Shell

Photo: Ylva Bengtsson



By: Malin Sundqvist

Dagdrivarn (www.dagdrivarn.se)