A DNA analysis revealed that only the Alaskan Inuit sled dogs—Eskimo dog and Greenland dog—are purely Americans. The rest were from other countries.

Peter Savolainen, lead author of the study and associate professor in Evolutionary Genetics at KTH-Royal Institute of Technology in Sweden, studied the origin of the dogs by analyzing its mitochondrial DNA. This was to settle the argument that all dogs originated from either Asia or Africa.

Scientists traced the earliest archaeological evidence for dogs in the U.S which revealed that they have been in the country for over 10,000 years, even before Columbus discovered the Americas. Based on the analysis, dog breeds such as the golden retriever, poodle, and others were of European origins. Only the Eskimo dog and Greenland dog were found purely American and may have come in the Americas along with the Native Americans.

“Nobody knows exactly what happened,” Savolainen wrote in the report. “Most probably migrated together with the humans that entered America from Asia via the Bering Strait. These humans became today’s Indians and Inuits. Our data shows dogs came in several migrations, at least one with the Indian-American ancestors and at least one with the Inuit ancestors.”

For the longest time, scientists believed that these dogs were of Siberian and European origins.

Another discovery based on the analysis was that the Chihuahua and Xolo (Mexican hairless dog) may be the oldest breed of pre-Columbian Mexican heritage. The Carolina dogs, which they believed to be from South Carolina and Georgia, are actually of Asian origins.

The study was published in LiveScience.

The result of the DNA analysis were aligned with the result of a previous research done by Sarah Brown of UC Davis and her team which also used DNA to trace the origins of the Alaskan dogs. The team plans to continue testing on other breeds to determine if dogs had been traveling with humans as far as 10,000 years ago.