Genetic abnormalities caused by extreme dog breeding are on the rise, while natural indigenous dogs with robust health are in danger of extinction.
The burden of genetic abnormalities in Canis familiaris, the first animal species that humans domesticated, has reached a critical state. Selective breeding for extreme abnormal traits, along with subsequent inbreeding, are to blame.
“An associated cost of selection for specific traits in breed dogs is an enhanced likelihood of (inherited) disease,” states a study published in December of 2015 in the Proceedings of the National Academy of Science. UCLA geneticist Clare Marsden and her colleagues examined the genomes of 46 dogs from 34 distinct breeds, and compared them with the genomes of 19 wolves, 25 village dogs and one golden jackal (a more distant relative of wolves and dogs). They found that, compared to wolves, breed dogs had 22% more cases of genes that had not one, but two, copies of a harmful mutation, because it was inherited from both parents. Compared with wolves, breed dogs averaged around 115 more mutations that posed some risk to their well-being.
The researchers concluded that their results “highlight the costs associated with selective breeding, and question the practice [of] favoring the breeding of individuals that best fit breed standards…. Considering that many modern breeds have been selected for unusual appearance and size, which reflects fashion more than function, our results raise ethical concerns about the creation of fancy breeds.”
The growing popularity of “designer dogs”, cross-breeds of two or more pure breeds, is in part generated by consumer demand for certain traits such as non-shedding and small or large size. The probability that such mixed breeds may have fewer inherited disorders than pure breeds because of “hybrid vigor” is undermined by the possibility that both parental lineages from two separate breeds carry similar recessive harmful genetic mutations. It is advisable for people purchasing a pure breed or designer dog to receive assurances of progeny testing for hereditary diseases from the breeder/supplier; and when purchasing either very small or large breeds, or those with extreme body conformation and skull shapes, to purchase a veterinary health insurance policy that covers pre-existing conditions of hereditary origin.
Comparing selectively bred dogs with native or pariah dogs
Veterinarian Dr. Wayne H. Riser was one of the first to identify health problems arising from selective breeding for sizes and shapes that did not conform to what he saw as the ancestral aboriginal/pariah dog. (See his monograph “The Dog: His Varied Biological Makeup and Its Relationship to Orthopaedic Diseases”, American Animal Hospital Association, 1985. For further details, see M.W. Fox, The Dog: Its Domestication & Behavior, Dogwise Publications).
This article will focus on my experience with the native dogs of the Nilgiris, South India, which I became familiar with while running an animal shelter and providing community veterinary services for a decade, starting in the late 1990s.
A profile of the natural dog
Natural, aboriginal dogs can still be found in many developing countries, especially in rural communities, as well as in the US, as detailed in my books Dog Body, Dog Mind and The Dog, Its Domestication and Behavior. One example is the so-called Carolina dog or American dingo, originally a landrace or naturally selected type of dog that was discovered living as a wild or free roaming dog by Dr. I. Lehr Brisbin. A breed standard has been developed by the United Kennel Club that now specifies the appearance of these dogs, which could be their undoing if genetic diversity declines. We have met very similar dogs from some of the Native American Indian reservations in Minnesota and the Dakotas.
In appearance, these dogs vary in size from 25 to 50 pounds, with many adults being undersized and underweight due to chronic malnutrition. They are long of limb, with usually erect or semi-erect ears. Tails are normally long and straight and are curled upward or downward in display, though some dogs have more permanently up-and-curled “Spitz” tails.
Normally, all these dogs are protective and very faithful to their owners. They have good musculature, and the males are clearly more robust and have more powerful jaws than the females. All have characteristically small paws relative to their size, as compared to most modern breeds. The females are more protective towards theirs puppies than non-native breeds; they will choose to whelp in a secluded place and may sometimes burrow a den. They will often nurse their pups for several weeks longer than other dogs do — pups may continue to be accepted as old as four to five months of age.
The native dog’s sense of smell and tracking abilities is considered superior to that of most imported European breeds. They are skilled hunters, and tribal people rear these dogs to guide them in the forest and to hunt smaller animals. These dogs also instinctively alert to the scent tracks of potentially dangerous panthers, tigers, wild boar and cobras, and are especially on the alert after dark. They are noted for their courage and tenacity, and will defend their owners from wild boar and sloth bear attacks. Around other domestic animals, such as chickens, calves and goats, with which they normally live in villages and tribal settlements, they are gentle and even protective, most probably as a result of selective breeding and training.
These dogs have great stamina and better resistance to many diseases when compared to imported breeds and cross-breeds. They are able to sustain themselves as scavengers, often existing on a subsistence diet that for other dogs would frequently mean rickets, stunted growth and other deficiency diseases. They show innate nutritional wisdom, and have often been seen eating mineral-rich dirt, and the feces of suckling calves, which are rich in enzymes, bacteria and protein.
The native dogs’ vocal repertoire varies considerably, and is generally rich and subtle in terms of sound combinations (like growl-whines, yelp-barks and pant-huffs), giving a clear indication of an animal’s emotional state and intentions. Some emit low “huffs” and growls when sensing danger, while others give full voice (not preferred when in the potentially dangerous jungle). They will give different barks when alerting to wild boar in the bush versus monkeys in trees, and will engage in coyote-like yip-yap howls when they sing in horal groups. One distinctive sound some of these dogs make in greeting is a coo-like twitter with high notes that sound like whistling, much like the whistle-call of the Dhole or Asiatic Wild dog.
The Nilgiris native dogs’ coat colors include black, red, tan, white, piebald and brindle. The most characteristic coat color is red (or ruddy tan), possibly a parallel or convergent adaptive coloration seen in the indigenous wild dog (Cuon alpinus), also known as the Dhole or Chennai, one of the few wild canid species that hunts in packs. (For more details, see India’s Animals: Helping the Sacred & the Suffering by D. L. Krantz and M.W. Fox, Createspace Books, Amazon.com, 2016).
Saving indigenous dogs
The Nilgiris native dogs, like other indigenous dogs around much of the world, are in a state of potential extinction due to breeders introducing foreign “exotic” European breeds that are seen as a status symbol. Many of these purebreds are deliberately crossed with the Nilgiris native dog, in part to help them adapt better to local conditions, which further dilutes and “contaminates” the genetic lineage of the indigenous dogs. Spay/neuter “birth control” programs have further reduced their numbers.
Outside breeds contaminating the gene pool of this native lineage in the Nilgiris include the German shepherd (Alsatian), Doberman, Labrador retriever, Rottweiler, terriers and hounds brought in decades ago by British people, and more recently by affluent Indian citizens. A policy decision to not neuter classic phenotypes of this now-threatened domestic dog variety would be a wise move in this and other bioregions where there are viable populations of relatively “pure” indigenous aboriginal dogs. This would allow the conservation of an ancient lineage, and preserve the beauty and temperament of the Nilgiris native dog (and other indigenous dogs), which some believe is the classic prototype of the earliest domesticated dog.
Cloning and gene editing
Like it or not, the age of bioengineering cybergenetics is upon us. Chinese biotechnology firm Boyalife and South Korea’s Sooam Biotech are building what will be the world’s largest animal cloning facility in China. But genetically engineered/edited and cloned animals often have genetic and developmental abnormalities and new diseases that cannot be justified for the novel pet trade.
Dogs have joined the list of species that have been genetically edited; that list includes pigs, goats, monkeys, rabbits and rats. In December of 2015, Laura Jacques and Richard Remde of Yorkshire, England, received two new puppies, Chance and Shadow, who were cloned using their deceased dog Dylan’s DNA. The couple paid roughly $100,000 to have Dylan cloned at the Sooam Biotech Research Foundation in South Korea. Meanwhile, in another cloning project, scientists in China used what is called CRISPR/Cas9 gene editing technology, which enables multiple genes to be simultaneously altered to create two beagles that lack some or all of the muscle-inhibiting protein, myostatin, resulting in dogs with larger-than-normal muscles.
These activities raise profound ethical concerns. For more info, see my article “Don’t clone your dog”, as well as my DVD concerning earlier developments, at drfoxvet.net.
The dark side of the human-animal bond
In a conference on the human-animal bond (Veterinary Record, December 5, 2015 p 558-559), University of Copenhagen bioethics professor Peter Sandoe observed that some people are attracted to and exhibit higher attachment to breeds with extreme (inherited) health problems requiring a higher level of care than healthy dogs. This observation implies there may be a Munchausen-by-proxy dynamic in some peoples’ choice of particular pure breeds and that “an owner’s love towards an animal does not necessarily translate into good welfare for that animal.” Sandoe concluded: “There is a dark side to human attachment to companion animals, alongside some of the benefits of ownership.” One favored dog gene has a human counterpart that has been implicated in Williams-Beuren syndrome, where it causes exceptional gregariousness and friendliness toward strangers.
In the West
Concerted efforts in the West to reduce the number of aboriginal/ indigenous dogs by various means (both humane and inhumane) for public health reasons (especially rabies control) may actually lead to the disappearance of landraces and the loss of genetic diversity in regional canine populations.