Tuesday, December 9, 2014

The history of dog breeds: Victorians, genetics, and the importance of diversity

Note: there is an interview with me at the Huffington Post about this story.

Dog breeds are amazing creations. I can own a series of Golden Retrievers and predict with fair accuracy how each of them will look and act. (Look more than act, but the incredible variety of dog personalities is a story for another day.) Unfortunately, I can also predict with fair accuracy what diseases each of those dogs will have, because with the Golden looks and personality come the Golden genetic disorders. As a new dog owner years ago, I thought of these genetic problems as part of the package I was handed when I got a purebred dog: you choose the looks and personality, and you choose the diseases at the same time. But there’s a lot more to the story of how dog breeds came to be saddled with particular genetic disorders than just happenstance: we made choices when we created breeds and we continue to make choices about their health today.




Figure from: Genome-wide SNP and haplotype analyses reveal a rich history underlying dog domestication Nature, Vol. 464, No. 7290. (17 March 2010), pp. 898-902, doi:10.1038/nature08837 by Bridgett M. vonHoldt, John P. Pollinger, Kirk E. Lohmueller, et al.



The beginning of dog breeds
Humans have been breeding dogs for thousands of years, but for most of our history with them, function was more important than appearance. Dogs were bred to work, and beauty was a side effect: long coats were for keeping warm, small size was for chasing tunneling vermin, long legs were for speed.

During the Victorian era, things changed, with the spectacular growth of dog fancy. Suddenly people were breeding and showing dogs for how they looked, not how they worked. Breeds were no longer loose groups of dogs who looked kind of similar and did a particular job; now for the first time purebred dogs had carefully maintained pedigrees. This was the era when the breed books closed, meaning that breeds were suddenly defined as the set of dogs whose ancestors belonged to a select list. If you wanted to make more Golden Retrievers, you could only breed dogs descended from that original list. If you bred in dogs with unknown ancestry, their offspring were considered mutts and could not be competitively shown, even if they looked just like purebreds.

What happens when you take a relatively small set of dogs and use them to breed a much larger number of dogs? It’s like this small set of dogs is marooned on a desert island with no way to bring in new genetic diversity, and their pedigrees are what marooned them. Their descendants will look like them and act like them – and have their genetic diseases. The genetics from those few founders are all that's available to the descendants. When this reduced genetic diversity is severe, it can be a big problem.

Basenjis and Fanconi syndrome
Reduced genetic diversity is severe in the Basenji breed. This breed originated in Africa, but only the Basenjis descended from a small number of dogs imported to Europe in the 1930s are considered purebred. The diversity in this breed was so low in Basenjis in the Western world that in 1990, one in ten Basenjis suffered from exactly the same genetic disorder, a kidney disease called Fanconi syndrome. One or a few of the founding dogs must have had this disease, and it was passed on to their descendants until a large percentage of Basenjis suffered from it.

The solution: bring in new Basenjis from Africa, breed them to the Western Basenjis, and declare that their offspring may be considered purebred, despite a lack of pedigree.  This was done in 1990 and again in 2013, and the effects are still spreading through the Western Basenji population over several generations. (You can read about the trip to the Congo to acquire African Basenjis.)

Dalmatians and urinary tract stones
But what if there isn't an ancestral population waiting to be harvested? Dalmatians also suffer from a genetic kidney disease, in their case stones in their urinary tract caused by high levels of uric acid. It's a painful disease and there was no way to breed out of it: at one point, every single Dalmatian in existence had uric acid levels above normal canine values.

The solution? The Dalmatian Backcross Project, which began in 1973 with the breeding of a Dalmatian to a Pointer. The project husbanded along a line of Low Uric Acid (LUA) Dalmatians, also known as Normal Uric Acid Dalmatians, because what's low in a Dalmatian is normal in any other breed. Puppies from this original Dalmatian/Pointer cross were tested for uric acid levels, and those with normal levels were bred to purebred Dalmatians. This continued generation after generation until a line of Dalmatians had been bred which looked like Dalmatians, not Pointers, but had normal uric acid levels. As of 2011, LUA Dalmatians have been registered with the American Kennel Club and are now considered purebred Dalmatians. It remains to be seen how long the problem of high uric acid levels will remain common in this breed, but at least now there’s a solution in sight.

What we're doing about genetic health in dog breeds
With these success stories, you’d think the problem would be solved. But these are the only two breeds so far to open their breed books to bring in new genetic diversity. [ETA: readers note that a few other breeds have opened their books, including Border collies, Chinooks, Salukis, and Azawakh in the US, and several breeds in Europe. Fantastic!] Both the Dalmatian and the Basenji had easy to diagnose, easy to understand health problems that were also easy to identify with genetic testing: problems controlled by a single gene. Such diseases are relatively unusual. Take the case of the Golden Retriever, who is prone to developing cancer at greatly accelerated rates compared to most other breeds. Cancer is controlled by a lot of genes and is very hard to genetically test for – and therefore hard to breed away from.

While introducing new genetics into Golden Retrievers is very likely to improve the health of the breed, it’s hard to convince breeders to take the leap. As was the case with the Dalmatian Backcross Project, such an undertaking would mean producing dogs that didn't look like Goldens for a few generations. They could still make great pets, but they couldn’t be shown and they probably couldn't be sold for as much money as a purebred. And there’s no guarantee that their descendants could ever be registered as purebreds – the fight to get LUA Dalmatians accepted was long and hard. I use Goldens as an example because I live with one, but many of the breeds we love suffer from low genetic diversity and associated genetic health concerns.

I believe we need as a society to get past our obsession with historical breeds. We can breed for appearance, but that has to take a back seat to breeding for health. We have a model with the Dalmatian Backcross Project. All we need is the will to improve the genetic health of more breeds.



Jack the Pumpkin King, my 14 year old Golden Retriever. He has so far only developed a small tumor, which was easily removed. However, he suffers from skin allergies and epilepsy, both genetic disorders.



39 comments:

  1. Thank you. Succinct and linkable. This is something that I've been trying to beat into the heads of my fellow rescue folks for several years now. Unfortunatley, the shelter/rescue people perpetuate the "breed only the best to the best" stereotype, and breeding for genetic diversity looks too much like "creating mutt puppies" to "compete" with shelter dogs (a myth, but a persistent one).

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  2. There are other outcross programs going on. Here in the US you have Chinooks, and the European kennel clubs have several in different breeds. The Finnish are notable in their efforts to maintain diversity in dog breeds, which is understandable considering their own genetic background. Salukis and Azawakh, two of my own breeds, maintain studbooks open to country of origin dogs, and there are others, like many of the livestock guardian breeds.

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    1. Thanks, I didn't know (though hoped) that was the case!

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  3. The ABCA (American Border Collie Association) does allow registration based on merit (requires a certain level of health and proven herding ability), which results in greater genetic diversity than an entirely closed studbook. The process is somewhat strict and has several steps, but it does happen that unpedigreed dogs become accepted and registered as Border Collies.

    There also exists the AWFA (American Working Farmcollie Association), which registers dogs solely based on merit and working ability. Granted, this is a registry for a landrace or type rather than a breed, and any farmcollie type or breed which demonstrates the working traits desired can be registered. It's a good resource for those interested in tracking certain dogs' traits and ancestry without closed studbooks, though.

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  4. The ABCA (American Border Collie Association) does allow registration based on merit (involves certain health requirements and proven herding ability). The process is somewhat strict and has several steps, but it does happen that unpedigreed dogs become accepted and registered as Border Collies, which results in greater genetic diversity than a strictly closed studbook.

    There also exists the AWFA (American Working Farmcollie Asssociation), which registers dogs solely on merit and working ability. They don't automatically register any offspring at all. This is a registry for a landrace or type of dogs rather than one breed, though, and in fact any farmcollie type dog or breed which demonstrates the desired working traits can be registered. However, it is a good resource for people who wish to see dogs' ancestry and traits, etc without a closed studbook.

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    1. Very interesting! Do you have details about the ABCA rules? I found http://www.americanbordercollie.org/ROM.htm which notes that "a pedigree of the dog should be supplied to the Secretary, giving all details available on the sire and dam, including registration numbers when available." Has anyone tried to ROM a dog with no pedigree?

      The AWFA program sounds great; I didn't know about that. As you say, it's a landrace not a breed (and more power to them).

      Thanks for the information!

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    2. I think they just ask for pedigree information so it can be documented if it's available. I've heard of a dog ending up ROM that was found in a ditch as a pup. I doubt this happens very frequently, but there's nothing in the rules preventing it!

      The AWFA is a wonderful resource :-). I'm happy to spread the word about it whenever I can!

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    3. The ABCA is a working stockdog registry and believes that breeding for conformation standards rather than working ability is detrimental to the health and working ability of the Border Collie. Consequently dogs or bitches which have been named a "Conformation Champion" by a conformation registry are not eligible for ABCA registration, even if they otherwise meet the requirements for registration. The ABCA will de-register any ABCA registered dog or bitch should it be named a "Conformation Champion" after January 1, 2004, and will not register the offspring of any dog or bitch named a "Conformation Champion" after that date.

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    4. So, to clarify for those who don't know:

      * There are other ways to register a dog other than through the best known American registry, the AKC;

      * The ABCA is not affiliated with the AKC (http://www.americanbordercollie.org/FAQs.htm#AKC)

      * As a working dog registry the ABCA is focused on working ability, not conformation (except insofar as conformation leads to improved performance, I assume)

      Thanks for this interesting information, Labella!

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  5. Several dogs have been registered on merit with the ABCA. Also, the ABCA is not a closed registry even without the ROM program; it accepts pedigrees from several other *working* registries originating on other countries, such as the Canadian Border Collie Association and the International Sheep Dog Society. I would also like to point out that the AKC--which co-opted the breed when it began registering border collies in the 1990s to the vehement objection of people who have continued in the centuries-old practice of helping develop and train useful working border collies bred to a working standard--has always kept its stud books open, encouraging the registration of border collies from the ABCA, because the organization knows that breeding border collies based on looks alone dilutes not only the working ability but also the health of this vibrant, hearty breed. As far as most working border collie folks go, we wish they would actually close their books and make formal the split between useful working border collies and kennel club show dogs.

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  6. Excellent piece, Jessica! Sharing! Also, as a geneticist and veterinarian, what is your opinion of the genetic diversity that is introduced with the development of Doodle breeds? We see quite a few Golden Doodles and LabraDoodles at our training school, and I find that I love their temperaments (as do their owners). Do you expect that these dogs will benefit, at least individually, from what used to be called "hybrid vigor", especially if they are the F1 generation? Do you know if there are any studies available yet regarding health problems in these new "designer" breeds? Thanks for another great blog! Linda

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  7. Hey Linda -- glad you liked it!

    I don't know of any studies assessing health in these crosses, unfortunately. They can still have predictable genetic diseases if there is a disease which is in both parent breeds! I wish I had solid evidence for hybrid vigor in these guys, but I just don't know -- all I can say is I would expect to see it.

    Note that this isn't really breeding in diversity to a breed, because designer crosses are typically not bred, or are bred back for one or two generations but not more. They aren't used to bring more diversity in to either of the original breeds. (I suspect Linda knows this but wanted to clarify for other readers.)

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  8. Thanks for this article. Sort of a shame, though, that the Huffington Post presented your ideas in way that seemed to say: "Science proves Goldens are great. Go out and buy one." What breed do you think would be a good candidate for cross-breeding health back into Goldens? http://www.michaelbrandow.com/

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    1. Great question and something I hadn't thought much about. A couple of approaches. You could breed in one of the breeds used to create Goldens in the first place (spaniels or other retrievers). Or you could try to get as much diversity in as possible and breed in a dog of very mixed breed! Whichever approach, you'd want to make sure the stock you used to breed in have none of the problems associated with Goldens (high rates of cancer, skin allergies, epilepsy, hip dysplasia).

      How about a more general approach: just allow the registering of any dog as a Golden who has at least a specified percent (95%?) Golden ancestry, passes a rigorous health check, and looks like a Golden?

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  9. Thanks so much for your thoughts. In the best of worlds, that makes such good sense. If only purists weren't attached to this archaic eugenic notion of blood purity and their snobbish belief in "aristocratic" lineage. The solution sounds so simple if only they'd get over that one hurdle, which I think is, more than anything else, working against the health of so many breeds.

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  10. Berners and flat coats also have these problems. The life expectancy of a dog should not be six!

    If anyone is interested, this project is working to nail down genetic issues in goldens in particular: http://caninelifetimehealth.org/ . If you're an owner, you can submit information and enroll your dog.

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  11. JPH! This is your old friend Laura Jones from Huntington! Imagine my surprise when I clicked a facebook link about Golden Retrievers (I almost always click links about Golden Retrievers) and saw your name. I googled to make sure, and it is you! Wonderful Huff Post interview, and wonderful blog. I lost my 16-year old Golden girl in July, so the subject is near and dear to my heart. I'm sure she and Jack would have been good buddies. Anyhow, so great to find you again! I Facebook friended you just to make it official. :)

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    1. HuffPo: uniting childhood friends across the globe. Great to hear from you! I just messaged you on Facebook.

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  12. I was just reading a article in the Huff post about golden retrievers. I thought it was wonderful until you got to the part saying Show breeders breed more for looks. I beg to differ!! Reputable breeders MUST show their dogs. This keeps a breeder from being a "for profit breeder" And yes there is some who forsake it all for the win, but many if not most are showing because the rules of the Kennel Clubs dictate we must. I invite you to visit me and look at my breeding program. My dogs, the health and longevity of my dogs, my very happy puppy clients, my over all knowledge of the breed because I AM A SHOW BREEDER and know more about this breed than you ever could.

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    1. I'm glad you liked the first part of the article :) Yeah, I know I differ from the perspective of a lot of breeders and I'm sorry about that. I do think that breeders have been dealt a rough hand in trying to manage the psychological and physical health of the dogs they breed while still trying to do well in the show ring. My problem isn't really with individual breeders -- there are plenty of quite reputable ones out there. My problem is more with the whole culture of placing conformance to a specific standard above being a good pet and easy to live with and being as healthy as possible. I think there are breeders out there who would rather breed for personality but they are swimming upstream when they have to make a choice: breed this dog who has a fantastic personality but is not quite up to the breed standard in a particular way, or breed another one? Goldens in particular suffer from the popular sire effect (a very small number of sires parenting a very large proportion of dogs of that breed - http://en.wikipedia.org/wiki/Popular_sire_effect) and I guarantee that those popular sires are chosen on the basis of performance in the show ring, not being good pets who are great with kids and easy to live with.

      So I salute you and all breeders who try to do right by their dogs in this culture. It's tough.

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    2. Why MUST a reputable breeder show their dogs? Especially when in most breeds, the extreme looks are what's going to win. This is what turned the golden coat to cream, from something serviceable, to mountains of fur and what made them from a working dog to dogs that could not hack it doing their original job.
      The show ring is all about who is the prettiest dog (and what owner/handler can schmooze the judge the most). It also breeds for less involved/intelligent dogs and they have shown that puppies from show stock compared to working stock are for lack of a better word, stupider.
      It's easy to understand why, especially with coat breeds. They breed dogs that are content with sitting in a crate for hours a day, minimal, monotonous exercise (tread mill anyone?) and the sometimes HOURS doing nothing while being groomed.
      Health is secondary. This is why Great Dane breeders have NO PROBLEM breeding harlequin to harlequin,even though 1 in 4 of the litter is going to be born deaf and blind due to the merle gene. Let's not forget the deaf and blind double merle sire of the winning rough collie in Westminster a few years back.
      Or the ringer studs that have had so many OFA xrays, as a stand in, it's a surprise the dogs don't glow in the dark.

      Yes, there breeders that try to actually improve the breed but they're few and far between and they'd do more if they put obedience and other working titles on their dogs, THEN a breed title. But how many can be bothered with that?
      When you have generation after generation of conformation show champions in working breeds and NO working titles? Tell me again they're improving the breed. Look at the pigeon chests on dobermans, to give the ILLUSION of chest depth, Look at the sloped back on the German Shepherd, to where they can't even walk properly, and are very reminiscent of Big Lick TWHs. And look at how Rottie and Boxer muzzles are getting shorter and shorter to where they can't even breathe when they run and boxers are dropping dead because they can't breathe and rotties can't even do bite work on a sleeve. And ZERO working titles in a 6 generation pedigree. And tell me again how a reputable breeder MUST show.

      So what if someone makes money off their dogs. People spouting that bit of nonsense is basing that on the fact that the beginning the show world was populated and ran by VERY RICH people. Name any high society name in the 1920s- 1950s, and you have the basis for the belief that you are not supposed to make money on your dogs. Read Lad a Dog and the Big Red/Irish Setter stories, and you will find what? RICH people who owned and showed these dogs, typical for that time.
      Not only that, but if you have a winning stud, you're not giving away stud fees. Don't tell me that these people are not making money breeding their males, that more than cover the cost of the dogs show career. A top stud can go for 5K to breed to, and even a cost of 2K 50 times a year is a pretty good chunk of change, especially since the dog will likely be bred for several years and have hundreds of litters registered to it.
      These people aren't making money off their dogs? The fact is if you can't do more than break even, then you're doing something wrong.

      It's ALL about the ribbon. The AKC can decide at any point in time that they will not allow the issuance of champion certificates if the dog did not pass CHIC breed tests. And before I let anyone pat themselves on the back for CHIC, a dog can FAIL every single breed health test, and still get it's number..

      There is a reason the AKC does not require the passing of ANY kind of health test before allowing Championship certification and that's because it's not about the healthiest dog, it's all about the prettiest dog, and the prettiest dog can be riddled with all kinds of genetic defects and pass them on because it is, in the end, the prettiest dog, according to it's standards.

      Maybe if reputable breeders got away from showing, they'd have healthier, happier dogs.

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  13. Our Dalmatian, pure bred, has Wilsons Disease, copper poisoning of the liver. It was discovered at age 9, with a full blood test, and a biopsy. She is doing fine on penicillamine, is now 12-1/2. Is this a Dalmatian trait? She was born deaf in one ear, and is a liver spot. The breeder is a Vet, who bred and showed Dals at that time.

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  14. Retry-I am not hiding, just did not know which source to use to comment. Cricket also is on Denosyl and Science Diet L/D. Further, we learned there is copper in our water, so we give her water filtered with Brieta filters which removes it, as well as lead.

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    1. I knew that copper toxicosis was prevalent in Bedlington Terriers but I didn't know it was in Dals. I looked it up, though, and apparently it has been seen in Dals as well and yes, is considered a genetic disorder in them -- their livers are not as good at processing it as the livers of normal dogs:

      http://www.akcchf.org/canine-health/your-dogs-health/disease-information/copper-toxicosis.html

      Sorry to hear about Cricket!

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  15. Sorry not very good with computers so commenting as anonymous. I think the popularity of a particular breed may contribute to the health issues specific to the breed. For example there are a bazillion litters of "AKC" labs born each year. In spite of all that is being said on this blog about show breeders many are actively attempting to improve the breed's health as well as looks.particularly with the rarer breeds. Here is a like to the research being sponsored by the Scottish Dearhound Club of America- http://sdcahealth.wordpress.com/research/degenerative-myelopathy-research/

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    1. I should have said more about this in the blog post but I really do believe that individual breeders are really hampered in their genuine efforts to improve the breed by the culture surrounding the idea of bringing in outside blood. There is indeed fascinating genetic research happening these days -- but it's hard to get rid of these bad alleles once they're found if your breeding stock has the bad alleles at very high frequencies!

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  16. Thank you for this article, which I found through HuffPost. Even though we have a Pomeranian from an exceptional breeder, we deal with effects of the breed's miniaturization – goopy eyes, teeth more prone to decay, the “reverse cough,” etc.

    Are you familiar with the American Alsatian, which is being developed by Lois Schwarz of White City, OR (http://www.schwarzdogs.com/index.html)? (No financial interest on my part.) The American Alsatian is a large to giant, non-working companion dog: virtually no barking, prey drive, fence jumping, or digging; highly trainable; healthy and long-lived; and calm and affectionate. These dogs want to stick around you and your house.

    Lois groomed and trained dogs for decades and realized that many people loved the large breeds but didn't love their working traits.

    One of her goals is to get close to the skeletal structure of the (extinct) Dire Wolf. Along with that, she breeds for health, temperament, and looks and periodically adds in whichever breed gets her toward her goals – Giant Malamute, Akita, Irish Wolfhound, Lab, among others, then breeds back toward the American Alsatian.

    She does detailed temperament testing on the pups, and her F1s, F2s, etc. are in high demand because she's honest about how each pup will differ from the ideal American Alsatian.

    Many of the AKC's practices infuriate me. It's encouraging to hear that people are outcrossing to improve the health of certain breeds, and that organizations exist such as the ABCA. Also, there's a rumor out there that, when some of the Irish Wolfhound folks got into lure coursing, they secretly outcrossed to Greyhounds for more speed. Supposedly, some IW lines are living longer as a result. I hope it's true. The short lifespan is the main reason we never considered living with an IW.

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    1. I didn't know about that. Fascinating -- thanks for sharing! Interesting to breed a giant size dog for health; I'll be curious to see what lifespans she gets in her dogs. I have a pet theory that it's not possible to get a giant size dog to live as long as a medium size one because they're just not meant to be that big. But hopefully I'm wrong because the giant breeds are so beautiful.

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  17. Our longest living dog was 150 pounds and 13 yrs old

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  18. Dr Hekman,
    Sorry to be back asking this at a late date but I was wondering:
    At what age did your sweet dog Jack first start showing signs of skin allergies, cancer, and epilepsy?
    Jack looks so great for fourteen, but the way.
    Thanks,
    Michael

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    1. He had skin allergies the day I got him (he was around 2 then) -- so hard to know when those started. I saw his first seizure a month or two after I got him, so hard to know if he'd had others before that. The little plasmacytoma was a few months ago, age 13-14ish.

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    2. Poor baby. Did the breeder have anything to say about this?

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  19. He's a rescue, so breeder is unknown. Honestly I think for a golden he's quite healthy -- no hip dysplasia, no bad cancer (yet), epilepsy is mild. The allergies are pretty bad but they can be managed with Atopica (expensive, but effective).

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  20. Sweet boy. Give him a hug! And thank you.

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  21. Dr. Hekman,
    Thank you for the wonderful article in Scientific American on cancer. I've published a book on the cultural roots of purebred dog problems (A Matter of Breeding, Beacon Press, Foreword by Marc Bekoff) and would be honored to send you a copy. For more info: http://www.huffingtonpost.com/marc-bekoff/a-matter-of-breeding-how-_b_6508972.html
    http://www.michaelbrandow.com/

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    1. Huh -- it sounds really interesting! Would you mind emailing me directly at jph at dogzombie dot com to discuss?

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