The MC1R locus is the control for "yellow" in Labs. There is a premature stop (termination, or ter) at amino acid 306 that (for lack of a better explanation) supresses the expression of the skin pigment (black or brown)in the hair. If the dog only has one of these R306ter mutations, then the dark pigment still shows in the hair. If there are two of them, then the hair is some shade of red/yellow. Your report shows that the dog's coat is "dark" - chocolate in this case - and the dog carries one mutation for yellow. You would think of this as bbEe in the typical notation used by many breeders.
