Silver Labs – By Amy Dahl, Professional Retriever Trainer and coauthor of “The 10-Minute Retriever”
…A couple of years ago I wrote an article on color genetics including mismarks, and as part of the research I spoke with Dr. Mark Neff at UC Berkeley, * one of the researchers on the dog genome project. Dr. Neff has collected pedigrees of silvers born to unsuspecting breeders and he believes the data indicate that the gene has been in the breed for a long time.
Dr. Neff told me that he didn’t know if the gene was identical, at the molecular level, to the “blue dilute” gene that occurs in a number of other breeds, but that its effect on the pigment, causing it to be clumped together rather than evenly distribute, is the same. This gene, recessive d (the dominant, non-blue allele is D) occurs in Dobermans and Weimaraners. The recessive blue coloration also appears in Newfoundlands and Chesapeakes.
In a Dobe, dd in combination with B gives “blue,” and dd in combination with bb gives “Isabella,” which resembles a Weim or silverpeake ( except it has tan points ). I have not seen a silver Lab, but they are said to be bb (genetically chocolate) with the recessive blue dilute. I’m also told that there are black Labs showing the blue dilute, which are described as “cast-iron” colored. These would correspond to a blue Dobe.
Dilution appears not to affect the yellow-red pigment, so it is not apparent in yellow Labs. If you had a yellow Lab that was bbddee, based on the color of my Chesapeake’s, I would expect it to have a grayish colored nose, but normal-looking yellow coat.
The earliest account I have found of possible “silver” Labs was a description of “blue-white” puppies whelped in Scotland in 1932. “Blue-white” is a pretty good description of a newborn silverpeake—and I’m guessing the puppies in Scotland didn’t live long enough for anyone to see what the color turned into.
To Review:
- A professional canine geneticist who has studied silver-Lab pedigrees, submitted confidentially, concludes that the gene has been in the breed a long time.
- The gene is easily overlooked, even when dd is present, because its effects are very subtle in yellows and blacks (Note that chocolates, in whom the dd combination is apparent, weren’t bred in large numbers until recently.)
- A gene with the same effect is present in both known related breeds, Newfoundland and Chesapeake
- The appearance at birth of Chesapeakes with the silver coloration fits the description of Labs whelped as far back as 1932.
In my opinion the evidence that the silver color is inherent to the Labrador breed is strong. In my opinion, I’m happy people are breeding silver Labs, and that AKC accepts their registrations. So many people want to be different, and get a dog that is different, and they get one of the other retriever breeds or a Boykin or Toller, or something else all of which have their merits, but people come to grief expecting them to act like Labs. The Labrador is the only Labrador.
Amy Dahl
Feb 15, 2007
Originally posted on RetrieverTrainingForum.net – Retriever Training Forum
(http://www.retrievertraining.net/forums/showpost.php?p=142153&postcount=5)
Reprinted here without endorsement expressed or implied.
- Mark Neff is presently Director of the Center for Canine Health & Peformance at the Van Andel Research Institute Grand Rapids, Michigan
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