Oct. 31 (UPI) -- Purebred dogs with a different color coat than their brothers and sisters are still purebred. According to a new study, purebred dogs with uncommon traits are usually evidence of gene variants at work, not proof of breeding flaws.
When researchers at Purdue University's College of Veterinary Medicine analyzed a dozen different genes in 212 dog breeds, they found several breeds host gene variants that yield alternate coat colors, patterns and lengths.
Scientists also found several other trait variants lurking in the genomes of popular dog breeds.
"These are purebred dogs with traits that their breed clubs say they're not supposed to have," lead researcher Kari Ekenstedt, an assistant professor of anatomy and genetics, said in a news release.
Ekenstedt and her colleagues compared their genetic analysis with the breed descriptions used by several American and international dog breed registries.
"There was a lot of information we didn't expect," said Dayna Dreger, lead scientist in Ekenstedt's canine genetics research laboratory. "When it comes to different dog breeds, their standards are mostly based on preference and aesthetics. We make assumptions for certain breeds based on what we expect their coat colors to be."
Genes that control coat color feature a significant amount of epistasis, which means dominant genes can drown out and mask the activity of other genes. The gene variant, or allele, that yields brown coats is accepted in Labrador Retrievers, but disallowed in Rottweilers and German Shepherds, breeds in which brown alleles exist at low frequencies.
Though some breed registries accept long and short haired varieties of the Weimaraner breed, other registries disallow longhaired Weimaraners. The new research, published this week in the journal PLOS One, revealed the longhaired allele to be present at a 4 percent frequency.
And while only 18 breeds are officially recognized as having the potential to be tailless, researchers found 48 breeds carry the tailless gene variant -- including the Dachshund.
"A breeder would certainly be surprised to see a Dachshund born without a tail," Dreger said. "The chances are low, but our research shows that the potential is there."
The authors of the new study say they aren't interested in creating new definitions for dog breeds, but they hope their findings will be utilized by dog breeders and others in the dog community to reconsider their expectations for purebred dogs.
"There's an assumption that the standards for these different breeds of dogs are set in stone," Dreger said. "People will often make assumptions that if it doesn't match this, it's not purebred. This data shows that there is a lot of variation in some of these breeds, and the standards are not as concrete as we expect them to be."