Based on new research from the National Institutes of Health, first dog Bo is once, twice, but not quite three times a mutant.
Researchers from the NIH and several universities have shown that variation among the coats of different dog breeds can be traced back to three genes.
Like about half of other Portugese water dogs, Bo possesses two mutant genes that contribute to the appearance of his coat of curly hair. What he lacks is a third mutant gene which would have given him the "furnishings," or a moustache and eyebrows, that are typically seen in dogs with wiry hair. Bo's lack of furnishings means that he has the ancestral form of that gene, matching the patterns found in wolves, according to the research.
"I think he's a perfect example of a Portuguese water dog, and a Portuguese water dog is an outstanding breed." It's an outstanding choice for the first breed," said Elaine A. Ostrander, chief of the cancer genetics branch of the National Human Genome Research Institute, the study's lead author.
She noted that the lack of eyebrows and a moustache was not a hindrance to Bo, a gift to the Obamas from recently deceased Sen. Ted Kennedy, who owned several Portuguese water dogs himself.
"You don't expect Portuguese water dogs to have that," she said of the furnishings. "He looks like a very typical Portuguese water dog."
And Ostrander acknowledged that, "We haven't tested Bo" among the 76 Portuguese water dogs looked at in the study. "If the Obamas would like to contribute, we'd be more than happy to," she said.
By studying dogs' coats -- a trait easily observed by the human eye -- researchers wanted to better understand how the genes affected the coats, leading, they hope, to more specific findings in the genome later on. While the coat gene was initially found in Portuguese water dogs, researchers used genomes from 903 dogs in 80 different breeds to reach their overall conclusions.
Portuguese water dogs were chosen for the study because they have two distinct kinds of coats: some with curly hair, like Bo's, but others with long wavy hair. According to the American Kennel Club, there is no preference among breeders for one of the two coats.
"Because it does come in two coat types, that would, obviously, be a great study breed," said Lisa Peterson, a spokeswoman for the American Kennel Club.
Breeders of Portuguese water dogs are also willing to work with researchers, so, "Bo is probably one of the better-understood breeds, in terms of genetics," said Neale Fretwell, chief geneticist at Gaithersburg, Md.-based Mars Veterinary, a division of Mars Inc., the confectionery and pet food manufacturer. "That's probably good news for Bo, because the genes of his brethren have been well studied."
Fretwell, who was not involved with the research, said that the results of the study match expectations, in that three genes had a large impact.
"It really mirrors what we see in dogs in general," he said. "What gives them their characteristic traits is determined by a small number of genes."
While the three genes accounted for most of the variation, they showed up and combined a bit differently in the different breeds.
"It's not just that you have three phenotypes [observable traits] that are completely independent," Fretwell said.