Showsight - July 2017

InPreservatIonWetrust• DanSayers continued

desired spotting. The study concluded that the distinguished spots and the uric acid defect are associated in the Dalmatian solely due to an abnormally close link of two disparate genes on the same chromosome. It also made it clear that the strict selection for spots had resulted not only in a gene for this breed-specific characteristic, but also for the uric acid defect. Both had become homozygous in the breed. Naturally, the decision of the AKC Board was controversial at the time, but it was also prophetic. As the study of canine genetics has advanced, more connections between phenotypic traits and the inci- dence of disease are being revealed. Serious fanciers are being confronted with scientific information that’s challenging the very foundations upon which our breed clubs have been built. When confronted with the suffering that results from dis- ease, reconstruction through carefully controlled outcrosses may be the only viable alternative. standards for restoration The NPS allows for a property to be celebrated for a particular time period, not just for the date of its groundbreaking or its current condition. By identifying a specific chapter in a build- ing’s life as being more significant than others, certain fea- tures may be modified or removed altogether. This approach to honoring an historic site is referred to as a “restoration” and requires greater vision for a project to succeed. In the dog

the language of the NPS, this sort of extreme departure from conventional wisdom would be classified as a “reconstruc- tion.” Reconstruction may be considered when a property — or a breed of dog — is threatened with vanishing either in pieces or altogether. The NPS advises that when necessary, a contem- porary solution may be required to interpret an historic value.

In terms of saving a breed from extinction, this approach would be used to “recon- struct” seriously defective genetic material through the introduction of healthy genes from a “non-carrier” dog of another breed. This course of action has been tried in the past, most notably in Dalmatians. In 1981, AKC’s Board of Directors approved a request to register two littermates, a dog and a bitch, that were five generations removed from a Dalmatian-Pointer cross.

Scientific data contin- ues to shed light on the complex associa- tion between a breed’s genotype and its phe- notype.

The outcross was part of a study begun ten years earlier in an effort to eliminate a defect in the metabolism of uric acid. (Too much uric acid in the blood can cause both dermatitis as well as bladder and kidney stones.) The hybrid offspring proved to have normal metabolism of uric acid, along with the kind of ticking associated with the Pointer’s coat. When these dogs were backcrossed to Dalmatians, nearly half of the offspring had normal metabolic function of uric acid, including five dogs with typical Dalmatian spots. These dogs proved that the gene for the defect was not required to achieve the breed’s

104 • S how S ight M agazine , J uly 2017

Powered by