Issue Statement 1: "Silver" Labrador Genetics and Terminology
Since in the mid-1980’s, the adjective “Silver” has become regularly used to describe the appearance of Chocolate Labradors that possess the homozygous autosomal recessive alleles “dd” at the D locus, found on canine chromosome #25. The gene at the D locus is commonly called the “dilution” gene but is more correctly termed the “melanophilin” gene or “MLPH.” The term dilution is used in a descriptive fashion in reference to the scattered and random nature of the pigment granules of the hair shaft found in “dd” Labradors, which is in contrast to the continuous and organized granules seen in non-“dd” Labradors. Initially, the term “Silver” applied solely to dilute Chocolate Labradors however, in time, it was understood that the MLPH gene also affected the appearance of Yellow and Black Labradors, to which the adjective “Silver” did not readily apply. Inasmuch as the appearance of these Labradors was not the same as is seen in the MLPH Chocolate Labradors, other adjectives were employed to better describe them, “Champagne” for Yellow Labradors and “Charcoal” for Black Labradors. Although the adjectives “Silver,” “Charcoal,” and “Champagne” are commonly used, it is clearly understood that the base genetic colors and hair pigment are “Chocolate,” “Black,” and “Yellow,” the breed standard-described colors for Labradors.