In one set of genes, black is the dominant color, and only a dog with a double set of the recessive genes will be a chocolate brown Lab. The other set of genes controls whether a dog can be yellow.

Chocolate-coloured Labrador retrievers have, on average, 10% shorter lives than black or yellow Labradors, according to a study we co-published today in Canine Genetics and Epidemiology.Ear ...