Dog has been man's best friend for 33,000 years, DNA study finds
Editor's note: This article contradicts previous findings that it was the domestication of dogs that allowed humans to outcompete the Neanderthals in Europe somewhere around 40,000 years ago.
Ergo, it was domesticated earlier in Europe.
It's previously been thought that wolves likely were domesticated by European hunter-gatherers more than 18,000 years ago.
Man's best friend came about after generations of wolves scavenged alongside humans more than 33,000 years ago in south east Asia, according to new research.
Dogs became self-domesticated as they slowly evolved from wolves who joined humans in the hunt, according to the first study of dog genomes.
And it shows that the first domesticated dogs came about 33,000 years ago and migrated to Europe, rather than descending from domesticated European wolves 10,000 years ago as had previously been thought.
Scientists have long puzzled over how man's best friend came into existence but there is conflicting evidence on when and where wild wolves were first tamed.
So in one of the largest studies of its kind Professor Peter Savolainen and colleagues sequenced the genomes of 58 members of the dog family including grey wolves, indigenous dogs from south-east and north-east Asia, village dogs from Nigeria, and a collection of breeds from the rest of the world, such as the Afghan Hound and Siberian Husky.
The DNA analysis published in Cell Research found those from south-east Asia had a higher degree of genetic diversity, and were most closely related to grey wolves from which domestic dogs evolved.
Prof Savolainen, of the Royal Institute of Technology, Solna, Sweden, said this indicates "an ancient origin of domestic dogs in southern East Asia 33,000 years ago."
It is possible an "ecological niche unique in southern East Asia" provided an refuge for both humans and the ancestors of dogs during the last glacial period, with a peak between 26,500 and 19,000 years ago.
Davis, John, circa 1550 - 30.12.1605, English navigator, discovered the northwestern sea route to India and China
Prof Savolainen said: "The mild population bottleneck in dogs suggests dog domestication may have been a long process that started from a group of wolves that became loosely associated and scavenged with humans, before experiencing waves of selection for phenotypes (mutations) that gradually favoured stronger bonding with humans, a process called self-domestication."
So the history of dogs may involve three major stages including loosely engaged pre-domesticated scavengers, domesticated non-breed dogs with close human-dog interactions, and breed formation following intense human selection for diverse sets of traits.
Prof Savolainen said: "The study of Chinese indigenous dogs thus provide missing links that connect these three major stages."
The researchers said around 15,000 years ago, a subset of ancestors began migrating towards the Middle East and Africa, reaching Europe around 10,000 years ago.
Although this dispersal is believed to have been associated with the movement of humans, the first movement of man's best friend out of south-east Asia may have been self-initiated.
A tiny dog in a sweater sits in his owner's hand near the Forbidden City in Beijing, China
This may have been owing to environmental factors, such as the retreat of glaciers, which started about 19,000 years ago.
Dogs from one of these groups then travelled back towards northern China, where they encountered Asian dogs that had migrated from south-east Asia. These two groups interbred, before spreading to the Americas.
Prof Savolainen said the domestic dog, one of our closest companions in the animal kingdom, has followed us to every continent of the world and, as a single species, embodies one of the largest collections of DNA diversity for any on earth.
He said due to their cognitive and behavioural abilities, it has been selected to fulfil a wide variety of tasks including hunting, herding and companionship with the genetic and historical basis of these gene changes intriguing the scientific community, including Darwin.
But despite many efforts studying dog evolution, several basic aspects about the origin and evolution of the domestic dog are still in dispute including several different geographical regions as the proposed birthplace of domestic dogs, and estimations of the date of divergence between wolves and dogs of between 32,000 and 10,000 years ago.
The researchers said around 15,000 years ago, a breed subset began migrating towards the Middle East and Africa.
His team analysed the complete DNA of 12 grey wolves, 27 primitive dogs from Asia and Africa and a collection of 19 diverse breeds from across the world to show south east Asian dogs "have significantly higher genetic diversity compared to other populations."
Prof Savolainen said: "Our study, for the first time, reveals the extraordinary journey the domestic dog has travelled on this planet during the past 33,000 years."
Chinese indigenous dogs live in the countryside and were sampled across rural China, including many remote regions in Yunnan and Guizhou in southern China.
The breeds include dogs from Central Asia (Afghan Hound) and North Africa (Sloughi), Europe (eight different breeds), the Arctic and Siberia (Greenland dog, Alaska Malamute, Samoyed, Siberian Husky, and East Siberian Laika), the New World (Chihuahua, Mexican and Peruvian naked dog) as well as the Tibetan Plateau (Tibetan Mastiff). These dogs were chosen to cover as many major geographic regions as possible.
Earlier studies have suggested wolves may have been domesticated by the first farmers about 10,000 years ago in the Middle East or Asia, possibly to guard livestock.
But the latest study has found it began much earlier, long before the development of agriculture.