The Crux of the Problem Picture

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 x-rays 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 x-rays 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 pre-eminence 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 considerably 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.

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