What is the genetics of the black Golden Retriever?

A Golden Retriever’s coat color usually ranges from cream white to maple-leaf red, and its offspring’s color is very stable, basically only yellow. However, because the Golden’s ancestor was a black curly-coated retriever, a chance genetic mutation produced a golden dog, and after repeated selective breeding the stable gene was established. So Goldens can indeed carry the black gene, and atavism can produce a black Golden Retriever.

But black atavism is very rare; most of the black Goldens sold in large numbers on the market are mixed-breed dogs, and they are sold at very high prices.