A Primer on the Genetics of Color
Breed Standard: The Labrador Retriever coat colors are black, yellow and chocolate. Any other color or a combination of colors is a disqualification. White hairs from aging or scarring are not to be misinterpreted as brindling.
Black - Blacks are all black. A small white area on the chest is permissible and sometimes, will fall out with the puppy coat. This comes from the ancestor of the Labrador Retriever, the St. Johns Water Dog. The earliest photo of a Labrador Retriever is of "Nell" taken in 1899 (see "Know Your Breed"). You will also sometimes see white spots on the feet; this is found in the descendants of English Dual Champion Banchory Bolo (1915 – 1927) and are called "bolo marks".
Yellow - Yellows may range in color from fox-red to light cream, with variations in shading on the ears, back, and underparts of the dog. There is no such thing as a "White" Labrador; it is a Yellow Lab with a white or cream colored coat; likewise, there is no such things as a "Fox Red" Labrador; it is a Yellow Lab with a red-ish coat. A Yellow Lab with a dark chocolate nose is actually genetically a Chocolate dog with a yellow coat.
Chocolate - Chocolates can vary in shade from light to dark chocolate; a white "ring" around the tail is common and typically falls out with the puppy coat. Chocolate with brindle or tan markings is a disqualification. Chocolates have "chocolate" noses (formerly called Liver), eye rims and pads.
Disqualifications from the Breed Standard
A black with brindle markings or a black with tan markings is a disqualification. (A small white spot on the chest is permissible.)
A thoroughly pink nose or one lacking in any pigment. (Traditionally called a "Dudley".)
Eye rims without pigment.
Any other color or a combination of colors other than black, yellow or chocolate as described in the Standard.