http://abcnews.go.com/sections/scitech/Living/doggenome031015.htmlHow Dog Genes May Save People - Canine CuresHow Humans’ Best Friend Could Also Become Their Savior
By Amanda Onion Oct. 15 — Long before Shadow the poodle attained fame for becoming the first dog to be genetically mapped, a shaggy briard named Lancelot had already been shaking paws with lawmakers in Washington.
Since 2001, Lancelot has been a living model of how vision can be restored to the blind, and the gene therapy treatment that gave the briard sight is currently being vetted for human trials. But now that scientists have Shadow's mapped genome as a tool for finding new genes, there may be more medical miracles like Lancelot to come. "Many genetic diseases in dogs resemble human diseases and probably share the same genes," said Ewen Kirkness, the leader of the team at the Center for Advancement of Genomics in Rockville, Md., that decoded Shadow's genes. "This will make the hunt for those genes easier." Blind Dogs See Kirkness' work showed that dogs share about 18,000 of some 24,000 clearly identified human genes and they host about 360 of the same genetic disorders that are known in humans. He explains that researchers can use the rough draft of Shadow's genes to zero in on regions where problematic genes are located. Tracing genes in dogs is made even easier by the fact that dog breeders have kept decades worth of genetic histories for many breeds. Kirkness says all these factors will help accelerate research. In fact, they already have. Case in point: Lancelot. The briard and his two siblings were born in 2000 with a hereditary blindness condition known as Leber's disease. The puppies constantly smacked into furniture and huddled in corners. By studying the dogs' genes, researchers were able to pinpoint the genetic source of their blindness. To treat Lancelot and his brother and sister, researchers injected a virus containing corrected copies of the gene into the dogs' retinas. Within 90 days, Lancelot and his siblings showed signs of sight. <snip>
Linda Cork at Stanford University has traced genetic causes of motor neuron disease, cerebellar degeneration and other brain disorders in Doberman pinschers. George Lust at Cornell University is studying genetic roots of hip displaysia in Labrador retrievers. "We have regions of genes identified, but it's very early," said Lust. "The genome is critical — we need that information to design markers to find candidate genes." Perhaps some of the best promise is for those with rare diseases that might not normally be the subject of much investigation. Labora, for example, is a very rare and uncurable form of epilepsy. Doctors know about only 200 human cases in the world, but many purebred miniature wirehaired dachshunds suffer a kind of twitching disorder that is a mild form of the human disease. Research to cure the animal may help doctors find a way to treat the human form. <snip>
A study from the American Society for the Prevention of Cruelty to Animals estimated that about 100,000 dogs are used in medical research every year, while 2 million to 3 million are euthanized by shelters. For better or for worse, Chader also believes the genetic work could help breeders create the "perfect dog." By identifying problematic genes, breeders will be able to selectively breed them out or even treat dogs with the condition using gene therapy (although this would likely be prohibitively expensive). "Everything we shy away from in humans — breeding for smarter, taller kids, choosing eye and hair color — we may not do that in people," said Chader. "But we will in dogs."