The study's authors said domestication also occurred 11,000 to 16,000 years ago, but exactly when that happened is hard to determine because of the flow of genes between domesticated dogs and gray wolves, the Los Angeles Times reported. Dogs and wolves evolved from a now-extinct, wolf-like canid, with the split taking place at the time domestication took place, they said.
"Dog domestication is more complex than we originally thought," said co-author John Novembre, an associate professor in the Department of Human Genetics at the University of Chicago.
Researchers arrived at their conclusion by studying the genomes of three wolves from Asia, the Middle East and Europe, and comparing those to genomes of three dog breeds -- basenji, dingo and boxer -- and a golden jackal.
"We find standing variation in AMY2B [amylase] copy number in wolves and show that some breeds, such as dingo and husky, lack the AMY2B expansion," the authors wrote. "This suggests that, at the beginning of the domestication process, dogs may have been characterized by a more carnivorous diet than their modern day counterparts, a diet held in common with early hunter-gatherers."