Scientists generally agree that there is good evidence that dogs were domesticated around 15,000 years ago.
Researchers also point out that of the estimated 1 billion dogs in the world, only a quarter of them are pets. The vast majority of dogs run free in villages, scavenge food at dumps, cadge the odd handout and cause tens of thousands of human deaths each year from rabies. They are sometimes friendly, but not really friends.
The way to find the recipe, Larson is convinced, is to create a large database of ancient DNA to add to the soup of modern canine genetics. And with a colleague, Keith Dobney at the University of Aberdeen, he has persuaded the Who's Who of dog researchers to join a broad project, with about $2.5 million in funding from the Natural Environment Research Council in England and the European Research Council, to analyze ancient bones and their DNA.
Scientists at museums and universities who are part of the project are opening up their collections. So to gather data, Larson and his team at Oxford have traveled the world, collecting tiny samples of bone and measurements of teeth, jaws and occasionally nearly complete skulls from old and recent dogs, wolves and canids that could fall into either category. The collection phase is almost done, said Larson, who expects to end up with DNA from about 1,500 samples, and photographs and detailed measurements of several thousand.
Larson is gambling that the project will be able to determine whether the domestication process occurred closer to 15,000 or 30,000 years ago, and in what region it took place. That's not quite the date, GPS location and name of the ancient hunter that some dog lovers might hope for.
Larson is no stranger to widely varying points of view. He is an American, but recently became a British citizen as well. His parents are American and he visited the United States often as a child, but he was born in Bahrain and grew up in Turkey and Japan, places where his parents were teaching in schools on American military bases.
"I think everybody there thought I was with somebody else," Larson said.
But he could move dirt and speak Russian, and he had some recently acquired expertise — in college drinking games — that he said was in great demand at night. By luck, he said, the researchers on the dig turned out to be "the great and the good of British neolithic archaeology." One of them was Chris Gosden, chairman of European Archaeology at Oxford, who later invited him to do a one-year master's degree in archaeology at Oxford. That eventually led to a Ph.D. program after he spent some time in graduate school in the United States.
After receiving the grant from the council in England, he and Dobney organized a conference in Aberdeen, Scotland, to gather as many people involved in researching dog origins as they could. His pitch to the group was that despite their different points of view, everyone was interested in the best possible evidence, no matter where it led.
In November in Brussels, holding the priceless fossil, Germonpré pointed out the wide skull, crowded teeth and short snout of the 32,000-year-old skull — all indicators to her that it was not a wolf.
Germonpré says she thinks dogs were domesticated some time before this animal died, and she leans toward the idea that humans intentionally bred them from wolves.
He and Allowyn Evin, now with the National Center for Scientific Research in Montpelier, France, also took many photographs of each jaw and skull to do geometric morphometrics. Software processes detailed photographs from every angle into three-dimensional recreations that provide much more information on the shape of a bone than length and width measurements.
Germonpré and Arden agreed on a spot in the interior of the skull to cut. In the laboratory, he used a small electric drill with a cutting blade to remove a chunk the size of a bit of chopped walnut. An acrid, burning smell indicated that organic material was intact within the bone — a good sign for the potential retrieval of DNA.
Larson hopes that he and his collaborators will be able to identify a section of DNA in some ancient wolves that was passed on to more doglike descendants and eventually to modern dogs. And he hopes they will be able to identify changes in the skulls or jaws of those wolves that show shifts to more doglike shapes, helping to narrow the origins of domestication.
Although the gathering of old bones is almost done, Larson is still negotiating with Chinese researchers for samples from that part of the world, which he says are necessary. But he hopes they will come.
If all goes well, Larson said, the project will publish a flagship paper from all of the participants describing their general findings. And over the next couple of years, researchers, all using the common data, will continue to publish separate findings.
Other large collaborative efforts are brewing, as well. Wayne, at UCLA, said that a group in China was forming with the goal of sequencing 10,000 dog genomes. He and Larson are part of that group.
Last fall, Larson was becoming more excited with each new bit of data, but not yet ready to tip his hand about what conclusions the data may warrant, or how significant it will be.