This is part of a multi-page html document by Bonnie Dalzell, © 1997

Dominant Black - currently assigned to the A locus
Abbreviation = A

Dominant black. Little has assigned this to the A locus. The effect of this gene is to produce a uniform distribution of black over the entire surface of the animal resisting the dorsal-ventral color gradient and supressing any banding of individual hairs so the black color is distributed evenly along the entire length of the guard hairs, at least in short coated dogs with minimal undercoat.

In dominant black greyhounds who are allowed to grow a winter coat the undercoat is grey rather than black but the guard hairs are black.

There is some controversy about wether there are different genes that produce an all black dog. In most species solid black is a recessive color since the mechanism for generating solid black is to turn the cycling of melanine production off so that times of supression of melanine production do not occur.

There is no doubt however in my experience that the solid black in Borzois acts as a dominant gene. The definitive test as to wether it is an A locus gene would require breeding a proven a-y a-y red to a dominant black who carried a-t to produce what should be an A a-y dog, then breeding this dog to an a-t and see if only dominant black and a-y reds were born or if dominant black, a-y reds and a-t dogs were born. While the presence of all three colors in a litter would argue against dominant black being on the same locus as a-y and a-t, its absence would have to be an absence over a significant number of puppies.

In my breeding programs so far I have not had any litters to disprove the hypothesis that dominant black is an A locus color. Dominant black dogs are often affected by the action of G the dominant gene producing premature graying in black areas of the animal. There is some premature graying showing on the sides of the muzzle of the dog below. 


Barnabas Dominant black phenotype
       |       A             |   ?
-----------------------------|--------
Ishtar |a-t| A a-t (Dom Blk) |  a-t ? (blk/tn) (4)

 a-t   |   |                 |
pheno- | ? | A ?  (Dom Blk)  |  a-t ? (agouti) (2)
type   |   |                 |
The barnabas to ishtar breeding produced dominant black, black and tan and the color we are calling grizzle. (See picture).

A sampling of Breeds in which the dominant black gene A is common.

Greyhounds and Whippets
Labrador retrievers
They are almost all dominant black, the yellow ones are extension locus dilutes of dominant blacks, the chocolate ones are B locus dilutes of dominant black.
Chespeake Bay Retreivers
The chocolate ones are B locus dilutes of dominant black.
Great Danes
The blue danes are D locus dilutes of dominant black.
Border Collies
Borzoi - rare until a few years ago.

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