Monday, May 14, 2012

Mismark Case Study: Shar-pei

Thanks to the new Blogger I wrote this post a while ago, but forgot about it after it was buried under a number of other posts. I used to keep my unpublished posts always visible, so it's taking a little time to get used to.

A show dog in perhaps the most commonly seen color in the breed: red. The standard allows all shades of red to include cream, black, blue, liver/chocolate/brown, Isabella/lilac/fawn, and sable.
A bone mouth shar-pei
To the Western world, our knowledge of this rather unusual looking breed is usually restricted to the type seen in the show dog above. However, a number of traits can vary greatly. Overall, the breed can be split into two major types: meat mouth and bone mouth. Meat mouth dogs are like the one above: heavily wrinkled with a puffy muzzle and lost of excess tissue overall. In contrast are the bone mouth dogs, considered to be a better representation of what the breed once was, which has far less wrinkle and less exaggerated tissue overall.

Another point of variation that many people aren't aware of are the coat variations and color variations. There are three coat types: horse, brush, and bear, with bear being disallowed by the standard. In addition, there are a wide variety of colors. The vast majority are acceptable, but a few are not. Here are the mismarks:
  • A non-solid color other than sable 
    • Flowered (aka piebald, parti-color, spotted)
    • Brindle
    • Black and tan
  • Albino

Though these are all mentioned in the standard, some are far more common than others. Albino, for example, may not even be present in the breed, let alone dogs in general. If it is, it's likely to be nearly indistinguishable from very pale cream dogs with skin diluted by both the liver and blue genes. If the gene is present, it's a simple recessive for which carriers cannot be easily distinguishable from non-carriers. Brindle and black and tan are quite unusual, but do still occur on occasion. Brindle is dominant to non-black/brindle (aka sable), but would be hidden by dominant black and recessive red. Black, though on the same locus, is dominant over brindle. Recessive red hides any and all black pigment that would have otherwise been expressed. Both of these genes are known to occur in the breed. Black and tan, in contrast, can be hidden by basically every other color seen in the breed. It's recessive to sable as well as hidden by dominant black and recessive red. Since all of these things are true, it makes it quite likely that the genes will never disappear from the population. Instead, they will remain hidden until the right cross causes the color to pop up.

Flowered liver
Flowered, by far, is the most common and well known of the shar-pei mismarks. It's caused by a couple of recessive genes: piebald and extreme white. The acceptable colorations according to the standard are all genetically solid. However, considering how common the flowered coloration is, quite a number of these dogs also carry a copy of either the piebald or extreme white genes. When the right two dogs come together, they will produce puppies with white.

Flowered red
I have also found evidence for the occasional dog with a copy of the Irish white gene, which produces the marking pattern most often associated with such breeds as the border collie. Some shar-pei breeders do not consider this coloration part of the "flowered" term. However, since the coloration is also a mismark for the same reason as the dogs with more white, I prefer placing them in the same category. It also appears that a very large portion of the flowered shar-peis you will find are also ticked. As such, the breed as a whole likely has quite a number of individuals that are genetically ticked, but this can't be seen due to a lack of white markings.

Flowered black
The reason why flowered dogs pop up so frequently is likely due to the breed's history as part of the dog fancy. Like so many breeds, only a small number of dogs were used in the creation of the lines that continue to be bred today in countries like the United States. According to analysis by one breeder, due to the small gene pool basically every single shar-pei that exists today is related to a flowered dog. This makes it rather likely that they will themselves carry the gene. In fact, it's estimated that one third of the population are carriers. The color remains fairly controversial, partly since the reasons for its exclusion from the standard are rather ambiguous.

Flowered red with a blue mask
All in all, there really is no reason that flowered dogs should be considered unacceptable in the shar-pei breed. One of the biggest reasons to allow the color comes down to genetic diversity. Shar-peis suffer from a startlingly large number of inherited diseases that have come from their small founding population and selection against certain colors and characteristics and for the exaggerated, wrinkled type that is so well known today. It's really quite amazing. Since this is such an issue, and so common at that, genetic diversity if precious. It's likely that there have been many flowered dogs who are far healthier than some of the dogs that are ancestors of the dogs you see in shows today. It's unfortunate that a silly aesthetic preference has led to the irreplaceable loss of genetic diversity. In the shar-pei, out-crosses could go a long way in trying to alleviate these genetic issues, and such groups as bone mouth shar peis and mismarked meat mouth shar peis could be very helpful additions to the gene pool.

Sources are American Kennel Club, Chinese Shar-Pei Club of America, University of Saskatchewan, Royal Shar-Pei, and Jewel's Shar-Pei. Images are from Wikimedia Commons or Flickr.com and are under Creative Commons licenses or are copyright free: one, two, three, four, five, six.

2 comments:

  1. A shar pei thing I learned recently: apparently there are many shar pei/chow-type street dogs in China, called Tang dogs. These dogs carry the flowered colour, as well as many other shar pei and chow features - high ears and tail carriage (sometimes coiled), wrinkled forehead and neck, and the flat, broad head as well as the rusty black colour prefered over pure black in shar peis.
    http://www.wvc.vetsuite.com/Uploads/general/2158/1178_Tang%20street%20dog%20cr.jpg
    (Basically a smooth-coat chow)
    http://www.hkshar-pei.com/site_images_system/user/Flower_tang10.jpg
    (I think this flowered tang dog has a particularly beautiful shar pei "calabash" head)

    Anyways, the local dogs play heavily into the shar pei's heritage.

    http://www.hkshar-pei.com/index.cfm?pageid=115
    This site doesn't seem to be in your references and might contain interesting revelations. It's basically my only source of shar pei knowledge - I don't know how accurate it is, but the gentleman running it is obviously extremely passionate about his breed.
    Then again, bulldog breeders are passionate about bulldogs, but they clearly don't know what they're talking about when they tell you its story...

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    Replies
    1. Thanks for the info. I haven't heard of the Tang before, but considering how common street dogs of fairly consistent type are in certain areas I'm not surprised to hear of it's existence. I can definitely see the resemblances to both breeds.

      I have indeed seen that website before. In fact, I think it may be one of the first websites I ever ran across years ago that used the term "bone mouth." I do tend to take breed histories with a grain of salt, but some of the things he says do sound quite appropriate.

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