Man's best friend may have been his companion for far longer than believed, scientists have reported, publishing an analysis that dates domesticated dogs to more than 27,000 years ago.
Humans possibly domesticated the animals between 27,000 and 40,000 years ago, according to Swedish researchers whose work was published Thursday in the journal Current Biology.
The scientists based their analysis on an ancient Siberian jaw fragment. Previous estimates said modern dogs diverged from their wolf ancestors 16,000 years ago after the last ice age.
The "Taimyr" wolf bone in the study, dated to 35,000 years ago, shows that the animal was the most recent ancestor of wolves and modern dogs.
"Dogs may have been domesticated much earlier than is generally believed," said Love Dalen from the Swedish Museum of Natural History.
Dalen said the only other explanation for the unusual bone was the less likely possibility that a major divergence between wolf populations took place at that time that gave birth to modern wolves while the wolf population became extinct.
The Taimyr wolf lived a few thousand years after Neanderthals disappeared and modern humans spread throughout Asia and Europe, the study said.
DNA analysis also showed modern Siberian Huskies and Greenland sled dogs have an "unusually large" number of gene in common with the Taimyr wolf.