A few years ago, the folk singer Tom Rush released an album that included some disparaging comments about the Chinese crested dog.
This wasn’t all that surprising, since these dogs are “little fluffy white guys” as Mr. Rush described his wife’s pets, the kind he was embarrassed to be seen with in the big-dog town of Moose, Wyo., where he lived. To escape notice, he walked them at night on long retractable leashes, an exercise he described as “Trolling for Owls,” the title of his album.
He may now find the gumption to walk them during the day, in Moose or anywhere else in the country. The breed has a newly discovered heritage: Scientists reported Tuesday that the Chinese crested dog is one of a handful of breeds that trace part of their ancestry to the first dogs to populate the Americas 10,000 or more years ago.
Heidi G. Parker and Elaine A. Ostrander and their colleagues at the National Institutes of Health, made the discovery in a large study of 1,346 dogs in 161 breeds that they conducted using some existing genomic information and by gathering DNA samples from people’s pets at dog shows and other events. They published the results in Cell Reports.
The research team was interested in both the general question of how dogs are related to each other and aiding the search for disease genes. Dr. Ostrander’s lab also works on human cancers, and dogs can provide genetic clues. The new paper does not focus on disease genes, however.
“We wanted to create a data set that would be a great reference,” Dr. Ostrander said.
Dogs were domesticated 15,000 or more years ago, scientists now think, perhaps in Asia or Europe or in both places independently. The fossil evidence indicates they accompanied the first people who migrated from Asia to America more than 10,000 years ago. But those dogs seem to have disappeared when Europeans brought their own Old World dogs over. Traces of ancient dogs in modern breeds have been glimpsed, but this study looks in depth at DNA from many individual dogs — 170,000 points in the dog genome — to find which breeds share large amounts of genetic material.
Greger Larson at Oxford University, a specialist in ancient DNA who studies the first appearance of dogs from ancestral wolves, said that there has been a big focus on the early stages of domestication. “What’s great about this study,” he said, is that it brings whole genomes to bear “on breed development,” which is something that appears to date back only 200 years. Before that, it seems there were types of dogs, like herders or guard dogs, but during the Victorian era, dog breeding became so mixed up that it is hard to trace breed ancestry back any further.
The new research confirms much historical evidence about breed creation and has some intriguing new findings, like the list of breeds that show the heritage of ancient New World dogs. The researchers found several breeds that shared large chunks of DNA not found in other breeds: the Chihuahua, Chinese crested dog, rat terrier, toy fox terrier, American hairless terrier, Mexican hairless (or Xoloitzcuintli) and Peruvian hairless. They concluded that the DNA most likely comes from ancient American dogs.
The Chinese crested dog, despite its name, seems not to have come from Asia at all. And the toy fox terrier is a lot closer to the rat terrier than to fox terriers. These terriers and the American hairless terrier seemed to be descended from what were called “feists,” dogs that were common in the southern United States and may have been a mix of European hounds and Native American dogs.
Among other discoveries, Dr. Park said they found that some behaviors, like herding, were developed more than once. It seems that long before individual breeds were created, herding dogs were bred independently in Britain, Northern Europe and Southern Europe.
The study shows how recent human movements affected dog breeds. For instance, traces of German shepherd were found unexpectedly in the Mexican hairless and Peruvian hairless, evidence that the dogs of the first Europeans in the Americas got around.
As for Mr. Rush’s dogs, they were not plain old Chinese crested dogs. As he pointed out, they were “powder puff apricot teacup” Chinese cresteds.
So he may decide he wants to stay on the night shift after all.