View Single Post
Old 12-11-2013, 10:44 AM   #20
pstinard
YT 3000 Club Member
 
pstinard's Avatar
 
Join Date: Apr 2013
Location: Urbana, IL USA
Posts: 3,648
Default

Quote:
Originally Posted by Mike1975 View Post
Thank you Phil for your reply!

This site for havanese and some other sites for poodles, were the reason I asked about the V gene (silvering gene).

Havanese and poodles also carry the Graying gene but its effects is somehow different than in yorkies, considering that both breeds have double coats instead of the singe coat found in our breed. Also they carry different alleles in other locii, so the final result is completely different.

In this quiz answer Quiz # 2 answer it says :



In a poodle site Color Genes in the Poodle I came across this :



It seems that havanese and poodles carry both genes (G and V) and their combination alters the final phenotypic result.

To add a little more confusion, Joan Gordon claims :


Color & Texture by Joan Gordon

Many stunning yorkies have maintained their TRUE (not enhanced) deep dark blue color to the age of 5 and sometimes later. On the contrary there are specimens that cant hold color up to 2 years of age. The blue dillutes and dilutes to a silver color and finally we come up with an almost white dog. Most of these dogs have routs of a darker color, but as the hair grows the dilution factor is so strong that can't hold correct color. Additionally these dogs have super silk quality, and amazing texture.
Somehow dilution factor of the Graying gene or the V gene or maybe both of them are connected to texture.
Moreover it seems to be a connection between gold and blue - in other words phaeomelanin and eumelanin.

To quote again Joan Gordon from http://dandugmore.netfirms.com/color.html:



My -short- experience with the breed, confirms Joan Gordon.
Light gold = light blue and rich gold = dark blue.

BUT on the other hand there is another cause of silver color, and that is lack of pigmentation in general. This can easily be seen if we check the skin under the blue, which should be pink instead of blue, or a very very light blue, meaning that there is not enough eumelanin.

It is also very interesting that both colors are connected through the patterns of each other - controlled by A locus. The allele responsible for their tan pattern is [As] (saddle tan) according to Malcolm Willis. Tan on the forelegs extends up to the elbow and on the hindlegs it extends from the foot to just below the stifle. As you have mentioned in a previous post, the tan is not coming up quite as far on the body as in other saddle tan breeds.

Under the blue coat, the skin has a bluish tint and under the tan coat the skin is pinkish in color. If the pink skin invades the blue skin or vise versa, we will get an unclear gold and an incorrect blue.

So how can we explain all these genetically?

As for the hypothesis concerning the incomplete dominance of Graying Gene, it can be probably explained through Red Legged yorkies.
I hypothesize that a Red Legged is a [gg] dog. When bred together they of course reproduce themselves (recessive homozygous) , but when bred with a [GG] dog they can produce a [Gg] dog.

Thanks again
Mike
It sounds like the jury is still out on whether the V (Silver) and G (Greying) loci are the same. From the definition on the poodle website (Color Genes in the Poodle), it seems that Yorkies, or at least my Bella, has what the poodle people would consider a Siver gene rather than a Grey gene. I base this conclusion on the fact that as Bella turned silver, the tips of the hairs were black, and silver grew in from the base. (The poodle site implies that Silver is gradual, whereas Grey is all or nothing: "The graying gene leads to a gradual accumulation of white hairs in both the inner and outer coat.... In silver dogs, as in blues, the transition from black to white for each hair is gradual, but occurs at an earlier age.") It looks like Joan Gordon agrees with this analysis, and also relates color to hair texture. Now whether or not this is a real distinction, I have to take their word for it. There is very little information about progressive greying and silvering in the canine coat color scholarly literature. Everything seems anecdotal at this point.

I agree with you about redleg Yorkies being gg--that's something I was thinking about before you brought it up.

I'll keep you posted if I hear anything back about Bella's DNA analysis, or if I spot a new research article.
pstinard is offline   Reply With Quote
Welcome Guest!
Not Registered?

Join today and remove this ad!