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    Understanding The Genetics Of Your Dog's Coat

    Have you ever wondered how your beloved pup got to be so unique? The answer lies deep down within their DNA, and the very make up of the genetic information.

    Like humans, your dog’s eye color, coat color, and even aspects of their personality are determined by what’s written in the DNA from the time of conception.  

    If you’ve ever taken your dog to the local park, then you know pups seem to come in every color under the rainbow.

    There are dogs with white coats, others with black and brown, some even with three different colors mixed. Keep reading to learn more about how your dog’s coat color is determined.

    DNA Isn't Simple 

    If you remember science class, then you’re likely familiar with the idea that DNA is not such a simple subject to grasp. After all, DNA is responsible for giving all living things their genetic instructions for the development and function. No simple task indeed. 

    The DNA of canines is similarly complicated. Everything about your dog from susceptibility to certain diseases to playful nature is determined by your pup’s genetic information. That makes DNA a pretty powerful tool at understanding everything from health to personality in canines. 

    Humans have 23 pairs of chromosomes, while dogs possess 39. Every dog receives 39 chromosomes from its mother, and 39 chromosomes from its father. Within these chromosomes are thousands of genes that determine various traits, including physical and health characteristics. 

    Every chromosome pair possesses what’s known as an allele. These are variant forms of a gene. When two dogs breed, each dog will pass on one allele from each location in a random fashion. This gives each allele a 50% chance of being passed on to the animal’s puppies. The allele that’s dominant will determine specific traits like coat color.

    Begins With Two Colors

    Despite the variety of dog coat colors you’ll see on your evening walk, you might be surprised to learn that only two pigments determine the color. These pigments are both forms of melanin. These two main pigments, eumelanin and phaeomelanin, both possess a default color which is black and red respectively. 

    It is your dog’s genes that decide how diluted this color will be. For example, while eumelanin is a black pigment, color variations that stem from it may include grey, brown, and light brown. Eumelanin is also responsible for eye and nose color. If a dog does not produce enough eumelanin, it’ll likely have a pink nose and blue eyes.

    The pigment phaeomelanin, or red, also creates a variety of colors, including orange, yellow, tan, gold, and cream. This color is actually produced in your dog’s coat itself, and only affects the color of the fur. This same color is what humans with gorgeous freckles can thank.

    The darkness of your dog’s coat is determined by melanin. The more there is, the darker your dog’s fur will be. Still, it’s important to note that the color isn’t always consistent; the hair can start light and end much darker. The cells within the hair follicles that are responsible for adding melanin to the hair are called melanocytes. 

    How Genetics Can Affect The Coat's Color

    Out of billions of base pairs of DNA that exist within a dog genome, only eight genes are associated with determining the color of your dog’s coat. The loci or the specific position on a chromosome where a particular gene is located, that help determine coat color include:

    • A locus (agouti): Determines coat patterns by alternating between two pigments
    • B locus (brown): Connected to colors like brown, chocolate, and liver. This may also change the color of the nose and paw pads
    • D locus (dilute): Responsible lightening coats from black or brown to gray, blue, or pale brown through a pigment dilution 
    • E locus (extension): This can create a black “mask” on the face that is common in many dogs
    • K locus (dominant black): Dictates dominant black, brindle (brown pattern), and tan colors 
    • M locus (merle): This mutation causes merle which is a spotted or patterned coat, common in Australian Shepherds
    • H locus (harlequin): Responsible for white dogs with black patches 
    • S locus (spotting): As the name suggests, this is connected to interesting patterns like piebald and particolor


    Understanding why your dog’s coat is spotted or merle or jet black is a journey in understanding your dog’s lineage. Breeders will use genetic information to match dogs and try to create more exact versions of what they envision.

    If your dog isn’t purebred, you can always opt for a simple dog DNA testing kit to learn more about its bred, personality, and what makes your pup unique.