Chocolate Labs have been known in the breed as long as the black and yellow Labs. However, it was not until the 20th century that they were recognized in the U.S. Until then, both yellow and chocolate Labs were less favored than the black Lab, and not considered good enough for showing. The chocolate color is not inherited as a simple recessive gene, which makes it difficult for breeders to establish a definite breeding pattern for producing consistently chocolate-colored dogs with the same color intensity and dark points. Some geneticists believe the chocolate color is produced through a modifying action by genes of partial dominance that dilute or blend with the color produced by genes for other colors.
