A lesson in basic genetics for dog-owners

Inbreeding is bad. It increases the frequency of homozygosity for deleterious traits.

There’s this little thing called pleiotropy. Selection is a powerful tool, but traits can have multiple effects, and extreme selection for peculiarities can have unpleasant side effects — you may think a pug’s curly tail is adorable, but it comes with all kinds of spinal ailments. And cute little doggies with cute little heads may have skulls too small for their brains, leading to syringomyelia.

If you’ve got an hour, this video is worth watching. Add pedigree dog shows to puppy mills as examples of animal abuse. Warning: there are scenes of dogs in extreme pain and distress here; not because anyone is directly harming them, but entirely because they’ve inherited a suite of damaging genetic characters that make their lives a misery.

The most appalling parts of the documentary are the responsible people behind the dog shows and the kennel club breeding programs that arbitrarily set ludicrous standards for show dogs. There’s a judge declaring that the German Shepherds with the weakened, ataxic hindquarters of their ideal is genetically superior, for instance. And then there are the photos of what dachshunds, beagles, and boxers looked like in the 19th century compared to the show dog ideal of the 20th — in just a little over a hundred years, we’ve bred this poor animals into a monstrous state.


  1. slignot says

    I promise this is going to be my last comment on violent dog incidents, so I’ll be directly referring to sources about the accuracy of statistics.

    Phere wrote the following and I want to explain why I feel so adamantly that people need to abandon this sort of wrong rationale for selective risk-assessment of what is in fact a domesticated predator.

    Time and time again it’s the rotts/pits attacking/maiming (more devastating in children as they are “eye level”). I don’t care how uncomfortable people get, the stats are there. There is a problem with the breeds whether they like it or not. Just last year a 4 MONTH old was killed by the family’s rott – the poor baby’s face was ripped off. [Emphasis added]

    While I initially linked to my “Fear of Dogs” piece that contained sources for the inaccuracy and misreporting of statistics, I am going to pull directly from those reputable sources now, since as was said, “the stats are there.” I note however, that shortly after insisting there are statistics verifying the claim that dog attacks “time and time again” are primarily the two most scapegoated breeds, the proof presented was an unsourced anecdote report of a tragic incident with a child. I don’t doubt that this particular incident fed right into the current media climate which publicizes and re-publicizes only the sort of sensational news that will get readership.

    I’ve said before that the way that dog bite incidents are reported leads people to believe (falsely) that 1. specific breeds are inherently more dangerous and 2. that we have some kind of dog bite epidemic. The dog bite epidemic problem is fairly easily dismissed, but the idea that specific breeds are repeatedly the perpetrators of terrible attacks is much more stubborn to deal with.

    A 2009 report Media Reporting on Canine Aggression done by the National Canine Research Counsel has some very helpful information.

    FICTION: Some breeds of dogs are more likely to seriously injure people than other
    breeds of dogs.


    FICTION: Whatever the AVMA and the CDC say, a search of newspaper archives for stories about dog attacks will produce a statistically valid sampling that can identify which breeds of dog are more likely to injure people.

    These are followed by

    FACT: The AVMA Task Force on Human-Canine Interaction reported: “An often-asked question is what breed or breeds of dogs are ‘most dangerous’? This inquiry can be prompted by a serious attack by a specific dog, or it may be the result of media-driven portrayals of a specific breed as ‘dangerous.’ . . . singling out 1 or 2 breeds for control . . . ignores the true scope of the problem and will not result in a responsible approach to protecting a community’s citizens.”2
    FACT: News outlets are in the business of reporting singular events. Statistical validity is not their job. They do not select stories for publication on the basis of random sampling techniques. Editors promote stories they believe to be of interest to their audience. Most incidents involving dogs, good, bad, or indifferent, are not reported at all.
    FACT: NCRC research has shown that media accounts over-represent incidents involving dogs presumed to be of breeds already trapped in the media headlights, and under-represent (or ignore) incidents involving dogs presumed to be of other breeds or types.

    To further complicate things, even the stories that are reported on specific breeds are often done so incorrectly. Visual examination to determine “breed” is very often totally wrong (even by those who make a career of working with dogs), and contributes to the problem of poor reporting.

    FICTION: News stories invariably include accurate breed attributions of the dog or
    dogs involved.
    FACT: News accounts regularly disagree about breed identifications. The breed attribution one associates with a particular incident may very well depend upon which news outlet one consults. The NCRC compares reports from as many media sources as it can locate, with all available official reports concerning an incident, in order to obtain the most accurate and complete information regarding all aspects of an incident.
    FACT: Visual breed identification of a mixed breed dog is likely to be contradicted by a DNA test. A study to be published in the Journal of Applied Animal Welfare Science points to a substantial discrepancy between visual identifications of dogs by adoption agency personnel and the breeds identified in the same dogs through DNA analysis. [Emphasis added]

    So perhaps you should say instead, “Time and time again, the only thing you read about is incidents involving rotts/pits attacking/maiming.” I’m reminded of the great Dara O’Briain sketch that it’s simply ludicrous to go counter factual corrections that crime is massively down by saying, “But the fear of crime is at an all time high.”

    So since we can see that dog bites are vastly reduced in U.S. cities from what they were forty years ago, and that media reporting is dubious at best, the arguments against the bogey-man breeds and dog ownership really seems to boil down to: “But the fear of bites by pit bulls and rottweilers is at an all time high.”

    It certainly seems, as expressed by the ASPCA here, that we are basing our ideas about pit bull type dogs and rottweilers on sensational anecdote like the death of the infant Phere mentioned. What we should be doing is measuring risk by evidence and scientifically rigorous examination of the statistics produced by the visual descriptions of breed.

    Anyone can swap anecdotes, and while they do tend to personalize and issue, they should always be backed up by facts. I suspect that for every scary dog bites family member/stranger story, we could find the opposite if reporting were equal.

    For example, to your horrible killing last year, I can point to the incredible heroism of a stray pit type dog that interceded on behalf of a woman and her young child as they were confronted by a knife wielding man, also last year. This animal did not savage this aggressor, but stood its ground between this woman and her two year old son and drove him away. The woman announced her intention (very understandable) of adopting the dog should no owner present themselves. While touching, this no more “proves” a good or bad nature for a type of dog.

    As for the size of animal that reacts aggressively, defensively or territorially, there are dogs both smaller and larger than our supposed killer dogs. Of course the size of the dog is going to be an issue in the severity of an attack. Even small dogs have a surprising amount of power and strength, so the larger the muscles and snout, they have that much more physical prowess. (Ever play tug-of-war with a corgi or beagle? Tiny legs or not, they have a lot of strength.) A long muzzled medium or large sized dog has a truly huge mouth if you watch it yawn. I think German shepherds, for example have giant mouths.

    That dogs are potentially dangerous is a given. Nearly all decisions we make are governed by evaluating risk against gain. But we as a species in many cultures have decided that the benefit in work, companionship and joy is worth the potential risk of bringing an animal like a dog into our lives and homes. What is needed is responsible dog ownership, and that’s as true now as it ever has been.