Pages

Sunday, January 8, 2012

Mismark Case Study: Miniature Schnauzer

A show miniature schnauzer with cropped ears and a docked tail in the color most commonly seen in the breed: salt and pepper. According to the AKC, the only other acceptable colors are black and silver and solid black. Image is from Wikimedia Commons under a Creative Commons license.
The miniature schnauzer is a common pet, and was likely bred down from the standard schnauzer by breeding to smaller breeds such as the poodle. Of the three schnauzer breeds (miniature, standard, and giant), it is by far the most popular, having been in the top fifteen most registered AKC breeds for many years. Other than the three acceptable show colors, there are numerous mismarks that will pop up:

  • White
    • Recessive red in inheritance, it is acceptable in some other standards
  • Liver/chocolate/brown
    • Black becomes brown
    • Can appear in any of the above colors
  • Piebald/parti-color
    • Coat color is "broken" by white
    • Can appear in any of the above colors
  • Platinum silver, wheaten, or false white
    • Not pure white, but more cream colored
    • Possibly sable

Except for wheaten, all of the above colors are inherited recessively. As such, even with selection against a color, it is nearly impossible for the color to be eliminated from the population. Crossing two dogs that carry the color will then produce a "surprise" mismark puppy. Inbreeding only makes these recessives more likely to pop up, since relatives are more likely to share the same genes than more distantly related individuals.

This schnauzer is white
White is quite probably the most common of the mismarks due to the fact that it is acceptable according to many breed standards other than the AKC. The disparity between breed standards sometimes confuses me, and this is one of those moments. White is well known in the breed, and many registries to accept it. So why don't they all? I can imagine that it's more than a bit frustrating to those who like to show their dogs in more than one country. If they have a white dog who proves to be all that the show community wants in a schnauzer, then they dog would not be able to go as far as it's more darkly colored counterparts.

This schnauzer is liver parti-color
Another mismark is liver. It is the same gene that will cause chocolate in Labradors, as well as the brown color seen in so many other breeds. Again, since it is recessive it is still quite likely to pop up in the breed. Any pairing that produces a liver puppy will also produce approximately half a litter of liver carriers. Since they are indistinguishable from their non-carrier siblings, it would be a silly thing to eliminate any of the dogs from breeding just because they are suspected to carry liver.

This schnauzer is parti-colored
Another mismark that is seen in the breed is parti-color. Parti-color is a common term used when referring to a piebald dog. In schnauzers, it may be difficult to differentiate some piebalds from non-piebalds due to the dilution of the red in the coat to a near-white or white color. Since some piebalds have a lot of color, the markings can potentially match up with the pale markings normally seen on salt and pepper or even black and silver dogs. In addition, a white patch on the chest may indicate a carrier of the piebald gene. White patches can also be obscured by the normal markings in salt and pepper or black and silver dogs. Again, it would be a pointless endeavor to try to completely eliminate the gene from the gene pool.

As with all purebreds, miniature schnauzers have a closed gene pool. Eliminating a single dog from that gene pool is eliminating genetic diversity. Genetic diversity is of great concern in a closed population. By adding color into the selection decisions, genetic diversity is being lost over a purely cosmetic variation. Miniature schnauzers were once supposed to be able to take down vermin. Hunting instincts have no correlation with color, and as such selecting against a dog just because its nose is brown is a silly concept. Why not allow for colors that are well known to occur in the breed? Color should no matter, and as such creating a standard that has mismarks is purely based on what amounts to canine discrimination.

2 comments:

  1. The picture of the show schnauzer if a Black and Silver!

    ReplyDelete
    Replies
    1. I don't know about that. The photographer describes the dog as a salt and pepper, so it's possible that it's all lighting making the dog look so dark. Plus, the dog has a number of characteristics that better fit the genes behind salt and pepper (agouti) rather than black and silver (tan point). This includes what appears to be pale hairs intermingled with the dark. Black and silvers don't have that.

      Delete