The origin of our canine companions is a hotly debated topic, as the dogs were said to be domesticated from wolves thousands of years ago until they became a man's best friend.

According to DNA evidences, dogs have been eating human food and have been able to digest starchy foods 8,000 to 4,000 years ago. What the scientists think is that they have domesticated from wolves when they moved towards settlements scavenging for food.

Lead researcher Dr Morgane Ollivier of ENS de Lyon, France, said that the domestication of dogs was brought about by the human cultural development, and that it started when hunter-gatherer societies have adopted agriculture.

"As it was absent in samples coming from hunter-gatherers' contexts, we linked it to the development of agriculture in early farming society," Dr Ollivier said. "This probably constituted an important selective advantage for dogs feeding on human leftovers within a farming context."

"It's a lovely example of parallel evolution of human culture (emergence of agriculture) and the dog genome."

Scientists are separated by arguments on how dogs became domesticated from wolves. One suggestion says that wolves were used as companions by the ancient hunters and gatherers until they were able to tame and train these wolves.

Another group of scientists suggest that based on DNA samples, the first domestic dogs appeared on both sides of the Eurasian continent more than 12,000 years ago, until they have dispersed with humans who were from the west. This has led the scientists to the belief that modern day dogs are a mixture of these ancient and separate descendants of wolves.

According to a prior study, today's dogs already possess the genes that enable them to digest starch and this is what sets them apart from wolves, and that dogs have been separated from wolves approximately 15,000 years ago.