Dogs may have first migrated to the Americas only about 10,000 years ago, thousands of years after the first human migrants reached North America, new research, involving an Indian-origin anthropologist, has found.
The findings could shed new light at how human populations have moved around over time, the researchers said.
Termed as the largest analysis so far of ancient dogs in the Americas, the study looked at the genetic characteristics of 84 individual dogs from more than a dozen sites in North and South America.
"Dog genetic diversity in the Americas may date back to only about 10,000 years ago," said University of Illinois graduate student Kelsey Witt, who led the new analysis with anthropology professor Ripan Malhi.
"This also is about the same time as the oldest dog burial found in the Americas," Malhi noted.
"This may not be a coincidence," Malhi added.
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For the study, the researchers analysed new DNA samples from ancient dog remains found in Colorado and British Columbia, and from a site in southern Illinois known as Janey B. Goode, near present-day St. Louis.
The Janey B. Goode site is located near the ancient city Cahokia, the largest and first known metropolitan area in North America.
Dozens of dogs were ceremonially buried at Janey B. Goode, suggesting that people there had a special reverence for dogs. While most of the dogs were buried individually, some were placed back-to-back in pairs.
In Cahokia, dog remains, sometimes burned, are occasionally found with food debris, suggesting that dogs were present and sometimes were consumed.
The researchers found four never-before-seen genetic signatures in the new samples, suggesting greater ancient dog diversity in the Americas than previously thought.
The findings appear in the Journal of Human Evolution.