French Bulldog Small Dog Genetics and Breeds

Our Standard has included basically the same color requirements and disqualifications since they were added in 1911. During the intervening 97 years, it has listed the following as disqualifications: solid black, black and white, black and tan, liver and mouse color. In the FCI (Fédération Cynologique Internationale) Standard, the term "mouse grey" is used (Mausgrau in German, gris souris in French). Since our color disqualifications were added the same year that a Conference of French Bull Dog Clubs of Europe, at which our club participated, developed the European countries' standard, it is clear that the "mouse" in the US Standard referred to the mouse-grey coat color shown by dogs expressing the recessive "blue dilution" (D/d) gene.

French Bulldog

French Bulldog  genetics of canine coat color is complicated because there are several genetic loci involved, some of which control the color and intensity of the pigments, and some of which control the pattern of distribution of these colors. Briefly, there are two types of pigment in dogs a light pigment (phaeomelanin)
which may range from reddish through yellow to pale cream; and a dark pigment (eumelanin) which is either black or brown. French bulldogs should carry only the gene for the black type of dark pigment and therefore should have only black noses, lips and paw pads.

Brown pigment in the coat or nose/lips/pads is unacceptable (and is the "liver" that our Standard deems a disqualification; it is also a DQ by the FCI standard). The light pigment gives rise to a range of fawn coat colors all phaeomelanin, but in various degrees of concentration to produce the range of pigmentation from red through fawn to cream. Some fawn Frenchies have a black mask, which is a recognized and acceptable coat.

French Bulldog

There is a "pattern" genetic locus that gives rise to brindle coats. Brindle Frenchies have a base coat of fawn hairs through which black hairs extend in bands to produce a coat ranging from a "tiger" brindle in which the fawn hairs predominate, to the more common dark brindles in which the black hairs predominate. In some of the latter, the black hairs are so numerous that there may be only a small number of fawn hairs arranged in one or more bands. Our standard refers to "a trace of brindle," which should have enough fawn hairs to demonstrate this pattern. There is no such thing as a "brindle hair" since brindle is a pattern consisting of a mixture of black hairs and fawn hairs.

French Bulldog another 'pattern" gene produces pied (piebald) in which the coat is white with pigmented patches most commonly located on the head, tail base, and "saddle". The pigmented patches may be either fawn or brindle, but in a brindle pied dog there must be enough fawn hairs visible in at least one of the pigmented patches to provide the brindle pattern, so that it is not the disqualified "white with black."
Another pattern gene gives rise to black-and-tan (black with tan points), also a disqualification in both the US and the FCI standard. While there have been some black and tan Frenchies, these are rarely seen.