Genetic Studies of Dog Coat Color
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The diversity of coat colors and patterns in the domestic dog provides an opportunity to investigate how evolution and artificial selection have shaped morphologic traits for which the underlying pathways are well-characterized in other model organisms. In many breeds of dogs, there is a characteristic pattern known as "brindled", in which alternating black and yellow stripes appear to emanate from the dorsal midline, often in a swirling pattern. |
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What causes brindling?
Brindling represents the action of pigment type-switching genes, but is not caused by genetic variation in either Agouti or Mc1r. Instead, brindled is likely to represent a new locus, not previously recognized in laboratory mice, at which variation may also be responsible for dominant inheritance of a uniform black coat. To learn more about the genetics of dog coat color, including the DNA sequence alterations responsible for characteristic coat color of Irish Setters, Golden Retrievers, yellow Labrador Retrievers, and black German Shepherd Dogs, please see these publications, and visit the website of our collaborator at the University of Saskatchewan, Dr. Sheila Schmutz.
Our Current Project: to find the gene responsible for brindle, black, and fawn
We are trying to understand coat color variation in breeds where the difference between brindle, black, or fawn is controlled by a single gene. Our approach is first to determine the approximate position in the dog genome where the gene lies by analyzing families, and then narrow down the exact position by examining DNA from individual dogs for sequence variants that correlate with fawn, brindled, or black.
What do we need from dog owners
Participation by dog owners and breeders is a critical aspect of our study. We would like to obtain DNA (cheek swab) samples from:
Akitas, Basenjis, Boxers, Bulldogs, Bullmastiffs, Great Danes, Greyhounds, Mastiffs, and Whippets
At present, we are soliciting two types of samples:
(1) Entire litters, their parents (and other relatives) of the following types:
in which there are multiple different colors present:
Parents
Offspring
Black X Fawn
where black and fawn pups were produced
Brindle X Fawn
where brindle and fawn pups were produced
Black X Brindle
where brindle and/or fawn pups were produced
(2) Individual dogs from the breeds mentioned above that are brindle, black, or fawn.
(Many dogs also have extensive areas of white or white spotting; this does not interfere
with our study but we are not currently investigating the basis of white spotting.)
If you (and your dog!) are interested in participating, please email Sophie Candille with a description of your dogs (breed, coat color, relationship to other dogs for whom you might be able to obtain a cheek swab) and your mailing address, and we will send a package containing a consent form, sterile brush, and additional instructions.
What do you get for participating?
We consider the dog owners and breeders that donate samples as partners in our study; in exchange for participating, we pledge to keep you updated and informed as our work progresses. One potential outcome of our research is a practical test to identify genetic carriers of determinants for brindle, fawn, or black. Equally important, you will have the opportunity to contribute to a better understanding of a signaling pathway that is relevant to several aspects of health and disease in many different mammals.