The findings should shed light on diseases that afflict both dogs and humans, because many dog breeds suffer from genetic diseases also seen in humans, such as blindness and autoimmune disease. Because dog diseases tend to cluster in certain breeds (hip dysplasia in Golden Retrievers, for example) there’s a better chance of finding the genes linked to these differences, says Ellegren.
Claire Wade, a geneticist at Massachusetts General Hospital in Boston and an author on the paper, is comparing genomes of Greyhounds and Rottweilers, two breeds susceptible to bone cancer, to hunt down the relevant disease genes. Her group eventually plans to search for genes involved in breast cancer, diabetes, and epilepsy. Scientists could also look for genes involved in psychiatric problems, such as obsessive-compulsive disorder, which afflicts some dogs and is treated with the same drugs used to treat humans.
The high-quality of their genomes puts dogs into the top tier of sequenced mammals, along with mice and humans. Furthermore, dogs have some distinct advantages over mice as organisms for studying human diseases: they live longer than mice and they share a lifestyle, and lifestyle-related diseases, with humans. “Not only do they share regions of our DNA, they share our sofas, our snacks, and our homes, predisposing them to [diseases] such as cancer and diabetes,” says Wade.
Scientists will also use the gene catalogue to uncover the genetic basis of behavior, such as why collies herd and pointers point and why some dogs are prone to aggression. These clearly inherited behaviors were one of the reasons scientists were originally drawn to canine genetics, says Elaine Ostrander of the National Human Genome Research Institute. “Now we have the tools to really study this,” she says.
The findings also give insight into the history of dog breeding. Scientists found that all domestic dogs are derived from the grey wolf, as was expected. But researchers also found evidence that many dogs alive today are probably descended from small founding populations that lived as recently as 50 to 200 years ago, suggesting that many dog breeds as we know them today emerged only recently. “So while there are dogs that look like modern breeds in, say, Dutch paintings from the 1600s, those dogs are probably not that genetically similar to today’s breeds,” says Wade.