Mismark Case Study: French Bulldog

This is another post I had drafted up. Since there was such a long gap between case studies, I decided to post this one as well.

A French bulldog is one of the breed's acceptable colors: cream.

The French bulldog standard is actually rather confusing in its definition of what is a "correct" color and what is not. This is what it actually says:

Acceptable colors - All brindle, fawn, white, brindle and white, and any color except those which constitute disqualification. All colors are acceptable with the exception of solid black, mouse, liver, black and tan, black and white, and white with black, which are disqualifications. Black means black without a trace of brindle. - AKC French Bulldog Standard

So, what it basically says that brindle, fawn, white, and brindle and white are acceptable plus any other colors except those listed. Which basically means no other colors.  My assumption is that the "other acceptable colors" includes such things as red, cream, sable, fawn piebalds, and dogs with masks. However, those could for the most part be included under the heading of "fawn." It would make much more sense to simply list the acceptable and unacceptable colors without the need to get so pointlessly wordy. Even worse is their wording on what is and is not acceptable pigment intensity to the skin and eyes. Namely, eyes must be dark and noses black except on lightly colored dogs. So, basically blue and liver aren't allowed, but according to this wording, a cream dog such as the one above could have a liver nose and be considered acceptable according to the standard. Anyway, on to the mismarks:

• Blue eyes
• Tan point
  
• Ticking
• White seen on dogs should be free of ticking spots
• Lack of stripes
• All black dogs must have at least one visible brindle stripe
• Non-black pigment
• Liver
• "Mouse" (apparently blue and Isabella/fawn)

This Frenchie has blue eyes

The exclusion of blue eyes in any standard that allows piebald dogs is...problematic. This is due to the fact that it is far from uncommon for piebald dogs to end up with blue eyes, particularly if one of their eyes is partly or completely surrounded by white. Dogs that are extreme white (aka extreme white piebald) are even more likely to have one or two blue eyes since the gene greatly increases the likelihood that the dog will have little to no white on its face. Both genes can and do occur in the breed quite frequently.

A black and tan dog

Tan point is quite unusual in the breed, but does pop up on occasion. Since it is a recessive gene, it can potentially be hidden under a wide variety of colors. Sable is dominant to tan point on the Agouti locus, and thus it is possible that sable dogs may carry the gene. Recessive red, which is seen in the breed, can hide every other color, including black and tan. It's also possible that some of the dogs identified as "black" or very heavy brindles could actually be tan point. This would be due to the layering you get between the Agouti locus (and thus tan point) and the black K locus (and thus brindle). Heavy brindle markings would make it nearly impossible to see the crisp tan markings that are present in the dog at left and would instead cause a dog to have few, if any, tan stripes visible on the legs.

This puppy has ticking

Ticking, though not addressed in the official standard, is seriously frowned upon by breeders, showers, and exhibitors. Ticking is caused by a dominant gene that is only visible on a dog with white markings. As such, any solid dog that has a copy of the gene is indistinguishable from solid dogs that don't. If a solid dog that carries piebald is crosses with a piebald or another carrier and that solid dog has a copy of the ticking gene, you would get surprise ticked puppies. Since it isn't even mentioned in the standard, I don't know why it would be frowned upon in the first place since "all other colors are acceptable."

A possible black Frenchie

The lack of stripes thing is also a bit odd, particularly when it comes to the preferences that are seen within the breed. Among the brindles, those that are mostly black are preferred. So, basically the fewer the stripes the better. Yet a solid black dog isn't okay? To be allowable, there has to be at least one tan stripe visible on an otherwise black dog. Having a single tan mark means the dog is basically black.

A black and white Frenchie

Moving beyond my earlier point about dark brindle and the tan point gene, piebald throws a bit of a wrench into the works. Since the preference is for dark brindles, the more white a dog has, the more likely that what few tan stripes it may have are hidden by that white. I would suspect that there are more French bulldogs that are disqualified for being black that have white markings than those that do not. I would also say that most people that are outside of the French bulldog breed would look at a lot of the show dogs that are out there and call them black. Even if some of the dogs that are disqualified for being black are genetically black, it's still quite possible that their appearance could be a surprise. Since recessive red is seen in the breed, it's quite possible that some of the recessive red dogs out there are hiding the dominant black gene.

It is also quite possible that black in French bulldogs is actually recessive black (which is on the Agouti locus), in which case any dog could be carrying the gene. If the right two dogs come together, then a surprise black could appear. The only gene that would prevent a dog with two copies of the recessive black gene from being visibly black would be the recessive red gene.

A liver Frenchie

A blue puppy

Finally, there is the disqualification of dogs with pigment other than black. Both the liver gene and the blue gene are recessive, and thus can be carried by practically any dog. The "mouse" color that is mentioned in the standard appears to refer to both blue dogs and dogs that are expressing both blue and liver at the same time, which is in other breeds known by such names as grey, fawn, Isabella, lavender, and lilac. However, the lilac coloration is seen least often of the three due to the need of the dog being homozygous recessive for both the liver and blue genes. As such, it's quite possible that "mouse" refers only to blue and the liver+blue lilac is completely ignored by the standard. This is what is implied by the French Bulldog Club of America. This amuses me somewhat since lilac can appear quite similar to fawn in color and since the standard allows for light pigment in light colored dogs, it's possible that a lilac could be considered acceptable.

A blue masked fawn

Anyway, such things simply distract from my overarching point. Except for a small possibility of blue dilution alopecia, there is nothing health-wise that would give a reason behind the exclusion of any of these colors from the standard. Thus, there really isn't any reason to exclude any of these "mismark" colors. The French bulldog is a companion breed, and as such arguments cannot be made for its working ability. However, color doesn't affect a dog's temperament, which is the biggest concern in a breed that is meant to be a companion.

Health in the breed is of even greater concern. The French bulldog has a number of issues, including serious breathing problems and a large number of their dogs being unable to give birth naturally. While these are caused by selection for short faces, large heads, and small hips, other problems are caused by a lack of genetic diversity in the breed. This list includes vertebral issues, luxating patella, and allergies. The vast majority of such issues are inherited and the reason why they become common in purebreds is due to selection and breeding methods. Heavy selection narrows genetic diversity by dropping dogs out of the gene pool entirely. By selecting for color, dogs who may be very healthy are being removed from a population due to a silly aesthetic reason. This has the potential of being very problematic for the breed.

Sources are the American Kennel Club, French Bulldog Club of America, Absolut Bullmarket French Bulldogs, and D'Accord Frenchies. Images are from Wikimedia Commons and Flickr.com under Creative Commons licenses: one, two, three, four, five, six, seven, eight, nine.