Color Riddle

Genetics - the sable skipped generations. It is like for people. My sister and her husband had a friend who was black. His parents and grandparents were white. Back in his lineage, an ancestor was black (I believe from Africa). This skipped a couple of generations and then showed up. Or the hair colouring in my mom's family - black, red and brown. Her parents did not have red hair.
 
Yes Im going to go with the skipped version...
My theory is if its in there somewhere back in the pedigree its going to pop out sooner or later!!
 
In the 1985 version of sheltie talk (page143) it talks about the unusual variations. It says: "There have been cases reported of recessive sables (actually brown) and dominat blacks. These are probably throw backs to early crosses with other breeds such as the spanial."
 
Oh, but the occasion for mistaken identity is sooo alluring! Sorry, the love of mystery runs thick within my veins.
 
The sable gene doesn't skip generations, at least Sable of the Agouti variation. It is dominant to all black genes.

If the bi-black dam had managed to get a dominant-black gene from somewhere, it might have covered up the fact that she carried sable. Dominant black doesn't occur in Shelties, which assumes mom is a mix of some variety.

I can't wait to hear this.
 
JessicaR said:
In the 1985 version of sheltie talk (page143) it talks about the unusual variations. It says: "There have been cases reported of recessive sables (actually brown) and dominat blacks. These are probably throw backs to early crosses with other breeds such as the spanial."
Click to expand...

Jessica is actually right.:smile2: The bitch was indeed bi black not a dark sable. But geneticly, she was suppose to be a bi factored sable and she is a purebred(absolutely no doubt). The sheltie does not normally carry the dominant black gene as seen in other breeds. But on rare occasions, some shelties can carry the dominant black gene.

The techinal answer lies in the interaction of agouti genes(Ay, at and a) and the K genes(Kb, ky). Kbr is brindle but it doesn't play the this discussion.

Sable dogs are Aya(bifactored sable) or Ayat(trifactor sable). Black dogs are aa(bi black) or ata or atat(tricolor). Dominant black is Kb and not normally seen in shelties. The ky gene allows other genes to detemine color. If a dog has 1 gene of Kb, the coat will be black regardless of the the agouti gene. Kb will also mask the points so the dog will be bi black. White markings is controlled by yet a seperate gene and unaffected by the 2 above genes. Most(almost all) shelties are kyky so the agouti gene determines color. Kb is common in the BC BTW.

The bitch in question was geneticly testing by Vetgen for the agouti genes Ay and a and the K gene and found to be Aya(bi factored sable) and Kbky(dominant black). Her bi black puppy maybe a normal bi or may carry the dominant black gene. The tris we know don't carry the dominant black gene because we see their points. Also it was discovered upon questioning that the bitch's dam also produced a sable pup in an all black breeding. The bi black pup was pet quality,placed and neutered so this branch of the gene ends there.
 
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