Purebred Dog Breeds into the Twenty-First Century:
Achieving Genetic Health for Our Dogs

Continued from page 3

The Crux of the Problem

As we face the millennium, the one problem which most concerns the entire purebred dog fancy is genetic defects. Breeders used to worry about overshot/undershot bite and cryptorchidism. Not much else of a genetic nature was cause for concern; fanciers were a lot more worried about distemper, hepatitis and internal parasites. Breeding programmes concentrated on individuals' visions of canine excellence. Then in the 1960s the tip of the genetic iceberg emerged as concern grew about a joint disorder called hip dysplasia. A control programme involving the examination of hip xrays by a skilled scrutineer and the maintenance of a registry of animals "cleared" of the defect was established at the Ontario Veterinary College at Guelph, Ontario. Now after three decades of the OVC programme it has been pretty well established that "clear" animals with several generations of "clear" ancestry can nonetheless produce dysplastic progeny [Chidiac-Storimans 1995]! Hence the OVC control programme would seem to be of questionable effectiveness. As the generations of closed-studbook breeding have advanced, a panoply of other inherited problems has emerged in purebred dog breeds. There is no need to list them here; the list would be on its way to obsolescence in a month or so; veterinary research continues to define more inherited disorders regularly. Many breeders now run four-way screening programmes; some may screen for even more problems. Many breeders' selection programmes for various kinds of canine excellence must now be at a standstill - all the selection is going into the effort to produce stock "clear" for eyes, hips, elbows, blood disorders, endocrine dysfunction, etc. Yet thirty years of xrays have not eliminated hip dysplasia - it is now widespread in breeds in which it was not a problem thirty years ago.

In December 1994, Time magazine published a scathing indictment of the American Kennel Club and of purebred dogs and their breeders, targeting in a cover story the problem of genetic ills, suggesting that the best use of pedigree papers was for housebreaking the puppies and recommending that the public satisfy its desire for canine companionship with mongrels. Since then, most of us have known we have an untenable situation on our hands. Our reputation as breeders of purebreds is now in tatters; we are caricatured in the media as greedy, uncaring producers of degenerate animals. The CKC's main response to the situation was a Board policy statement that "reputable breeders will provide a detailed written guarantee of the present and future good health of the dog and will not hesitate to uphold their guarantees." The policy statement, far from helping the situation, only saddled breeders officially with a heavy responsibility without enacting measures which might assist them in living up to it.

It is time for us as dog breeders to stand up for ourselves and for our dogs, to reject the imputation that we ourselves are individually to blame for the problem of genetic defects, and to demand swift remedial action by the Club and, if necessary, Agriculture Canada. The crux of the problem is the closed studbook and with it, the ideal of breed purity, the worship of type and the preeminence of the championship show as goal and arbiter of most breeding programmes. Armed with the concepts of population genetics, we can now examine the last: century of nineteenth-century dog breeding, ascertain what has gone wrong, and establish ways and means to correct the situation.

Earlier we stated that the recognition of a breed by a registry was a crucial event in its history, more crucial than it need be. That is because the usual practice has been to open the registry to foundation stock for a limited period, to inspect and register a small population of foundation animals, and then to close the registry to new genetic inflow forever after, with the sole exception of animals of the same breed imported from other registries and derived from the same or closely-related foundation stock. In recent decades there has usually been no unique Canadian foundation stock except in the case of indigenous breeds; CKC merely accepts registered stock from other jurisdictions. (Actually the relationship of CKC foundation stock to that of other registries has never been clearly defined, so far as I know. CKC accepts registration papers of other studbooks which it considers to be "reliable." So long as the export pedigree shows three generations of registered, numbered ancestry; import stock seems to be eligible for CKC status without question. The criteria involved are clerical, not genetic.) Most of the breeds we are familiar with were founded from sixty to over one hundred years ago. In those days Canada's population was much smaller than it is now; the canine population was correspondingly smaller, too. Thus the number of dogs accepted during the open-registry periods was rather limited.

The canine species possesses tremendous genetic diversity as a whole. Like most species, that diversity includes a genetic load, a wide variety of more or less deleterious alleles, probably quite a few of them held in a state of heterozygote superiority, so that although natural selection tends to eliminate homozygote recessives when they segregate, the bad alleles themselves maintain a strong presence due to the selective advantage of the superior heterozygote. What happens when a founder event occurs? Then it is possible that bad alleles, uncommon in the canine population as a whole, may achieve a much higher frequency of occurrence owing to their presence in a small founder population - especially since the foundation stock of a newly-recognised breed will already be considerable inbred from the breed development process. Inbreeding and selection together raise homozygosity levels dramatically through the wholesale elimination of alleles from the genome. Those alleles may be unwanted by the creators of a new breed; nevertheless their elimination raises the allele frequency of whatever remains.

An Example from One Breed

Thus the recognition of a breed creates a founder event when the registry is opened; a limited number of breed foundation animals are selected, often from a population which has already undergone considerable inbreeding and selection. Let us take for an example the Siberian Husky breed. Registered in 1939, the initial CKC population consisted of 47 animals, all belonging to or bred by one kennel! Of those 47, nine were foundation stock of the kennel whose dogs were registered. Two of those were males imported from Siberia - littermate brothers! The other seven were mostly related to one another. (Two were seven-eighths Siberian and one-eighth Malamute.) The other thirty-eight were all progeny and grand-progeny of the founders. Of the nine foundation animals, two were not bred from at all. Two were mated - once only - to each other: one only of their progeny contributed to further breeding. Of the two Siberia import males, one brother was always bred to the same bitch, producing a large number of progeny of identical pedigree; the other brother was usually bred to daughters of the first brother. Today Siberian Husky lines that trace directly back to the Canadian foundation stock owe 25% of their pedigree lines to the first brother, 15% to the second brother, and 27% to the first brother's invariable mate! Two-thirds of the genetic heritage of these modern Siberian Huskies derives from only three foundation animals! This is not an exceptional situation, it is a fair example of the early breeding history of CKC breeds.

In the case of the Siberian Husky, then, (which happens to be my breed, with whose early history I am reasonably well familiar), The Canadian Kennel Club opened a registry in 1939, inspected one kennel's dogs and admitted four dozen closely-related individuals to the registry, which was then closed permanently. No effort was made to ensure a broad foundation, nor a numerous one, nor a genetically diverse one.

Just how permanently the registry was closed I recently found out when I imported from Russia a dog bred to the Siberian Husky standard! The dog was born in the Ural Mountains well within the boundaries of Siberia from parents of Chukotkan village origins; he had three generations of known ancestry (without registration numbers since there is no official "Siberian Husky" registry in Russia). I was immediately told that the Club "did not know what to do" about my application to register the dog, that the protocols used to register breed foundation animals in 1939 were no longer valid, and that my dog "should not be used for breeding because it would probably be a long process," in spite of the fact that the dog had a valid FCI Export Pedigree from the Czech Republic (through which he was exported). A year and a half later after repeated in camera discussions, the import was refused recognition by the Board and Registration Committee on grounds of inadequate information (no ancestral registration numbers). Repeated calls for Club inspection of the import and offers to submit the animal to DNA tests and progeny testing were ignored. The registry is closed - even to new Siberia imports!

For the past fifty-six years, then, all Siberian Huskies bred in Canada have stemmed from the 1939 registrations, or from American imports, which mostly stem from the same dogs CKC registered, plus perhaps three additional animals. The original foundation animals were poorly utilised and subsequent generations were so closely inbred that the two Siberia import males plus one bitch are even today still statistically equivalent to grandparents of every single Siberian now registered!

Thus the original founder event in my breed plus the closed studbook has resulted in a state of forced inbreeding for Siberian Huskies. There is no such thing as an outcross mating in Siberians in any genetically meaningful sense. A sire can be found, perhaps, who may have no ancestors in common with a bitch for the last 5 or 6 generations - if one knows all Siberian bloodlines well enough and doesn't mind going a few thousand miles to find him - but he will not be an outcross, because all of his ancestors and all of the bitch's ancestors are the same animals, once the pedigree is taken back far enough. It would be difficult to calculate inbreeding coefficients for fifteen to thirty generations of ancestry; software to handle calculations of that nature doesn't seem to be generally available to breeders. (After all, a thirty-generation pedigree would contain over two billion names.)

Thirty generations of breeding all going back to ten dogs or fewer represents an impressive feat of sustained inbreeding! Predictably enough Siberian Huskies, which eighty-five years ago were probably the toughest, hardiest variety of dogs on earth, now suffer from the same gamut of genetic defects that afflicts other breeds. Few if any registered Siberians are now able to perform as sleddogs on anything approaching the level of the 1910 dogs imported from Siberia. Probably this is mostly due to the decline in heterozygosity and loss of vitality through inbreeding. What is worse, unmistakable signs of inbreeding depression are surfacing in the breed: rising numbers of Caesarean births, smaller litters, lower birth weights, delicate nestlings prone to infection, etc. Breeders of domestic livestock - cattle, poultry, sheep - manage to run registries and maintain breed type without imposing the concept of absolute breed purity. They inbreed to fix desirable traits, as do dog breeders. Livestock breeders, however, do not try to pretend that they can inbreed forever without ill effects. Thus when inbreeding depression or genetic defects threaten, they outcross - repeatedly, if necessary. They can do so because they do not have closed studbooks. I do not suggest that we slavishly copy the procedures and registry structures of livestock associations, because I think they, too, might benefit from some restructuring in the light of modern genetic knowledge. Nonetheless I would make the point that we in the canine fancy are in a minority when we cling to absolute ideals of breed purity and insist on rigidly closed studbooks.

As a dramatic contrast to the foregoing example of the CKC's Siberian Husky breed foundation, let us examine for a moment the standards which Agriculture Canada now applies to new domestic animal breeds in this country, as set forth in a three-page leaflet entitled "Establishment of a New Breed of Animals in Canada." Agriculture Canada now requires that breed foundation stock (that is to say, the first generation of registered animals of a new breed) be selected from the third filial generation (F3) or later of the "evolving breed" which precedes the actual, registered new breed. It lays down no parameters for the founder generation of the evolving breed, but it does state:

The standard used for the creation of a new breed is as follows:

It also stipulates that "the F3 generation is the earliest generation to become eligible for inspection as foundation stock... In practice most evolving breeds will evolve over many generations before having developed a significant population of foundation animals."

These modern standards are at least somewhat influenced by population genetics considerations, in an attempt to establish a basis for genetic health and stability for new animal breeds in Canada. Yet (in all probability very few of our existing CKC dog breeds, which are arguably of much greater economic importance than any new breed, would come anywhere near to the foundation stock numbers now enforced by Agriculture Canada. The sole exceptions would probably be breeds, like the Canadian Eskimo Dog, accepted for registration during the last decade or two. As for the Siberian Husky, its actual genetic founders (those whose genes contributed to future generations, leaving aside those which did not reproduce) numbered 6 only; the Fl generation which actually reproduced numbered 8 individuals; the F2 generation which actually reproduced numbered just 5 animals; no F3 animals were registered in the first year of CKC registrations -- original founders. F1s and F2s were all registered together in the first year.

Thus it is obvious that the Siberian Husky, at least, could not begin to satisfy current Agriculture Canada standards for an appropriate number and variety of foundation stock to establish a new breed, when traced to its historic foundation. In all probability, few CKC breeds could do so. Yet the registry norms that are rigidly enforced by CKC, backed up by Agriculture Canada make the acceptance into the studbook of badly-needed new foundation stock a complete impossibility! Presumably Agriculture Canada has good and sufficient reasons justifying its standard for new breeds -- that being the case, then it is a curiously irrational situation that older, existing registered breeds not only are exempt from any such standard, but are actually prohibited from enlarging their founder group by the acceptance of unrelated primitive stock.

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