When researchers at Stanford University announced in August they had found the gene responsible for the sleeping disorder narcolepsy, their discovery also bore significance because for the first time, genetic clues from dogs helped scientists unravel the genetics of a human disease.

The researchers, who had studied narcolepsy in dogs during the past 20 years, observed a close similarity between human and canine narcolepsy based on physiological and pharmacological factors. Resources such as the canine genetic map, with its array of genetic linkage markers, helped the Stanford scientists isolate the precise location of the narcolepsy gene in dogs.

Centered at the Fred Hutchinson Cancer Research Center in Seattle, development of the canine genetic map has been under way since 1995. The effort, coordinated by Elaine Ostrander, Ph.D., director of the cancer center’s genetic program, and supported by the AKC Canine Health Foundation and Ralston Purina Company, involves collaboration among more than 50 scientists worldwide.

Research using the canine genetic map led to the development of five direct DNA genetic tests for dogs in 1998: cystinuria in Newfoundlands; stationary night blindness in briards; and von Willebrand’s disease in poodles, Pembroke Welsh corgis and Manchester terriers. Since then, additional DNA tests have been developed, along with linkage-and marker-based diagnostic tests.

The AKC Canine Health Foundation, a nonprofit organization founded in 1995 by the American Kennel Club, develops funding for canine health research with an emphasis on canine genetics. The foundation was the first organization to financially support research of the canine genetic map.

Deborah Lynch, executive vice president of the Canine Health Foundation, says, “Our emphasis is on helping dogs live longer, healthier lives. While the foundation funds both clinical and genetic research, advances in canine genetics lead to discoveries of genes that cause disease and development of genetic tests. As more diagnostic tests become available, they will help breeders produce healthier dogs.”

Purina began funding Ostrander’s genome mapping research in 1997. Purina support in the genome laboratory includes providing for a genetic analysis machine, called a LI-COR IR2, that is used to amplify and study specific regions of DNA. Purina also funds the appointment of Cathryn Mellersh, D.V.M., a postdoctoral fellow who assists in statistical analysis of data used in mapping genetic markers on the canine genome.

The Ideal Canine Map
The ideal canine genetic map would be composed of a large number of markers anchored to genes, Ostrander says. These markers would highlight regions of the canine genome likely to contain disease genes. When researchers study members of a family with genetic disease, the markers help them navigate across strands of DNA to find disease genes. “Markers have the best predictive value when they are very close to the disease gene in question,” Ostrander says. “Increasing map density further will improve the precision with which a trait can be mapped.”

Considering that the canine genome is organized very similar to the human genome, it is not surprising that a dog model was used in the human narcolepsy research. Many dog genetic diseases closely resemble human genetic disorders and are likely to be caused by mutations in the same genes, Ostrander says.

Source – Yahoo Pets

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