You can thank prehistoric Europeans for man's best friend, as scientists now believe they were the first humans to domesticate the wolves that would evolve into the modern dog.
In a study published in Science magazine, a group of researchers led by Olaf Thalmann from Finland's University of Turku determined the DNA of modern dogs compares closely to both ancient European canines as well as modern European wolves.
"We're pretty sure that Europe played a major role in the domestication of the dog," Thalmann told Reuters about the findings. Researchers believe Europeans first began domesticating grey wolves somewhere between 19,000 and 32,000 years ago.
For their research, scientists tracked the DNA from the fossils of eight ancient dogs and 10 wolves, then compared them to 130 modern dogs and wolves. What they found was that the modern dog DNA only matched up with wolves from Europe, not wolves from outside of Europe.
How the various dog breeds have evolved from grey wolves over time is still a matter of discussion. For example, a separate study from 2010 used genetic markers to find evidence suggesting smaller dog breeds evolved approximately 12,000 years ago in the Middle East.
"Modifying a wolf into a Chihuahua is clearly a long process and most of the active breeding has happened in just the last few hundred years," said Thalmann.