Researchers found that dog domestication took place 11,000 years ago, towards the end of the last Ice Age. This means they were domesticated before any other, and by a long shot.
Until recently, the genetic history of dogs was told largely from the DNA from modern dogs. But this has offered a limited picture, as a large part of the genetic diversity of early dogs was likely lost when modern breeds were established. Early studies of ancient dog genomes hinted at past changes that have taken place in the canine genome.
Now, to expand the pool of ancient dog DNA, scientists at the Francis Crick Institute, University of Oxford, University of Vienna, and archaeologists from more than 10 countries teamed up. They sequenced 27 ancient dog genomes, which they obtained from Europe, the Middle East, and Siberia, and which ranged from 11,000 to 100 years old.
Dr. Pontus Skoglund, co-author of the told BBC News: "Dogs are really unique in being this quite strange thing if you think about it, when all people were still hunter-gatherers, they domesticate what is really a wild carnivore - wolves are pretty frightening in many parts of the world. The question of why did people do that?”
The researchers first modeled the relationships inside of and between groups of ancient and modern dogs. They established that a 10,900-year-old dog from Russia was distinct from later ancient European, Middle Eastern, Siberian, or American dogs, as was the case with a canine lineage characterized by modern New Guinea singing dogs.
This allowed them to follow ancient canine populations as they moved and mixed, and compare these shifts with those in human populations. Sometimes, dogs’ travels paralleled those of people. For example, when farmers from the Middle East expanded into Europe 10,000 years ago, they took their dogs with them.
However, the history of humans and dogs hasn’t always intertwined perfectly. A major influx of people from Russia and Ukraine 5,000 years ago led to lasting change in the genetic make-up of Europe’s humans, but not its dogs. The study also showed that the ancestry of European dogs has become much less varied in the past 4,000 years.
Greger Larson, an author from the University of Oxford, said in a statement: "Dogs are our oldest and closest animal partner. Using DNA from ancient dogs is showing us just how far back our shared history goes and will ultimately help us understand when and where this deep relationship began."
The study provides major new insights into the early history of dog populations and their relationships with humans and each other. Still, many questions remain. The research team is now focused on trying to uncover where and in which human cultural context were dogs first domesticated.
The study was published in the journal Science.