All retrievers come in four basic colors. These colors are black and liver/chocolate, which are the only colors allowed in the curly-coated retriever. The other colors are the recessive red to yellow with black skin pigment and recessive red to yellow with brown skin pigment. Chesapeake Bay retrievers come in liver/chocolate and recessive red to yellow with brown skin pigment (the deadgrass ones are pale yellow in color). As far as I know Murray River curlies come in only liver. Nova Scotia duck tolling retrievers come in recessive red to yellow (usually darker gold to red) usually with brown skin pigment. However, some do exist with black skin pigment. These dogs have minor white markings on them, which were once commonplace in all retrievers. Golden retrievers are recessive red to yellow with black skin pigment, but a very rare minority have brown skin pigment. Most field line goldens are towards the darker end of that spectrum, while most European show line goldens are towards the lighter end of that spectrum. Flat-coats come in the red to yellow coloration with both brown skin pigment or black skin pigment, but their standard colors are black and liver. Labs are the only retrievers to have all four colors standardized. Labs also come in black and tan and a diluted liver color, both of which exist in no other retrievers.
A dog carrying the dominant gene for black is signified with “B,” while a dog carrying the liver/chocolate gene is “b.” A homozygous black Lab, flat-coat, or curly is B/B. A homozygous liver or chocolate is b/b. This is the only way that a chocolate can be expressed. If a dog is heterozygous, carrying the B/b genotype, the dog is black but it carries the gene for liver/chocolate.
But what about the red to yellow color? That is a gene that affects coat color only. It is a recessive color, so it can only be expressed when a dog has a homozygous e/e genotype. A black skinned yellow or red dog, which has a big black nose, is a dog that is a B/B or B/b in that genotype, but it has a homozygous e/e genotype for its coat color. If a yellow ro red dog has brown skin, with a brown nose and brown lips, the dog is a b/b with a homozygous e/e genotype for coat color.
If you breed a chocolate Lab, which is E/E and b/b, to a golden retriever which is e/e and B/B (which is what the vast majority of goldens are), the puppies will be E/e and B/b. The heterozygous E/e means that the puppies will not be red to yellow in color, and the B/b means that the puppies will be black instead of liver/chocolate!
Now, let’s say you take two black labs that are E/e and B/b. This combination that can get you all four colors in the same litter.
Labs and Chesapeakes occasionally come in brindle, but this brindling tends to be lighter than that of boxers and greyhounds. Brindle is almost extinct in the Lab. In fact, I’ve never seen one, but brindle occasionally pops up in the Chesapeake. I am not certain if this brindling in retrievers is determined by the same genetics as other brindle dogs. If so, then brindling is a dominant gene over a solid color gene. Boxer breeders know this genetics very well, because this is the main color genetics for that breed. Brindle is nonstandard in any retrieving breed, so we generally don’t deal with it.
Labs also have a dilution gene that pops up. Non dilution is dominant to dilution. Silver labs are diluted livers or chocolates, and that is why they are registered a chocolates. Charcoal labs are actually diluted black labs. The gene for this color exists in no other retriever. One theory is that this gene was introduced by a cross with a Norwegian elkhound. However, elkhounds aren’t this color at all. The real culprit for the color is more likely the weimaraner, which is another gundog breed that often has retrieving instinct.
So now you know the genes behind retriever color. And when someone tells you that he bred a golden retriever with a chocolate poodle to produce goldendoodles, you can tell him what color to expect in the whelping box!