Scientists have discovered - through a new genetic analysis - that hundreds of American dog breeds' ancient roots trace back to Asia.
The research also found that on average, less than 30 percent of the dog's DNA has come from Europe, which suggests that the animals came to the Americas with ancient humans who established pre-Columbian civilizations in one of the biggest migration across the Bering Strait, Live Science reported.
The Chihuahua was found to have originated from an ancient lineage of dogs in Mexico.
Domestication of dogs occurred in Asia about 30,000 years ago and fossilised evidence for domesticated dogs in America dates to about 10,000 years ago.
For their research, study co-author Peter Savolainen, an evolutionary geneticist at the Royal Institute of Technology in Sweden, and his team swabbed cheeks of 347 kennel club purebred dogs from the Americas, including Alaskan malamutes, Chihuahuas, Peruvian hairless dogs and several signature American breeds.
The researchers then compared their DNA with 1,872 samples from dogs in Asia, Europe and Africa.
The study has been published in the journal Proceedings of the Royal Society B.