Did you know that “Black Dog Syndrome” is really a thing? Earlier this week, we shared one of our fabulous black pups on Facebook, as well as a link to an interesting article on Petfinder about this syndrome that leaves black dogs languishing in rescues while their lighter furred friends get adopted. While I happen to be partial to a black dog, I do find it fascinating how color preference can influence adoption choices.

The article also made me wonder how genetics determine dog coat color. When I did a doggie DNA test for my black pup, it indicated four non-black breeds as half her makeup. Does the black coloring comes from the other half, or are the results wrong?

A brief Google search of the genetics of dog coat color gives me lots of websites too scientific for me to understand. Fortunately, one site simplifies the science enough to gain a cursory understanding of the genetics of color. 

  • Two pigments determine the color of all dogs.
  • Eumelanin is by default black, but genes can modify this pigment to be brown, grey or pale brown. 
  • Phaeomelanin (red) is by default gold or yellow, but also includes cream, tan and orange.
  • White hair occurs in the absence of pigment, and usually affects certain areas of the dog’s coat.  
  • These pigments also determine the color of a dog’s eyes, nose, paw pads, and nails.

There’s more to it, of course, but it gets complicated. There are dominant and recessive genes, and the combinations from mother and father can result in pups of different color and pattern combinations.

At this point in my research I have a flashback of studying Punnett squares in high school biology, and using them to determine the possible eye colors of offspring based on the dominant and recessive genes of each parent. Think of dog coat color in the same way; there are multiple coat color possibilities from the same set of parents. This explains why my copper-colored rescue with a pink nose has a brother who is black, brown and white with a black nose.

Breeders manipulate genes to maximize their chances of getting the traits they want in their puppies, but most rescue dogs’ coats are just the color nature made them. 

So my black-coated rescue clearly has some non-black genes in her DNA, but because she’s spayed we’ll never know exactly what they are. And that’s okay, because like all rescue dog owners, we’d love our pooches no matter what color they were!

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