The long relationship between humans and dogs has just been pushed back by tens of thousands of years, thanks to a small piece of rib bone found during an expedition to the far northern reaches of Siberia. And the genetics show that dogs split from wolves much earlier than we once believed.
The bone in question came from a wolf who lived over 35,000 years ago in what is now the Taimyr Peninsula in northern Siberia. Fortunately, a research team, led by Pontus Skoglund of the Broad Institute of Harvard and MIT, along with scientists from the Swedish Museum of Natural History, was able to sequence ancient DNA from the bone. And what they found was the previous estimate of wolf and dog divergence, which was believed to have occurred around 16,000 years ago, actually took place much earlier. Their new estimates place the split between 27,000 and 40,000 years ago.
"Dogs may have been domesticated much earlier than is generally believed," says Dr. Love Dalén, one of the authors of the paper that appears in the journal Current Biology.
This latest research helps clarify the murky history of dog domestication. In the past, the genetic evidence indicating a later date of domestication conflicted with fossil finds of dog-like animals among ancient archaeological sites, some as old as 36,000 years.
But those previous estimates were based on mutation rates that have now been recalibrated, based on this new sequencing. It turns out the mutation rates among Lupine species are much slower than previously thought, which coincides with an earlier split between wolves and dogs.
Their research also reinforces the fact that dog domestication was not a singular event, stemming from a single line of wolves. Previous studies have shown that gray wolves from as disparate locations as China, Israel and Croatia are equally related to modern-day dogs. And what these latest genetics show is that high-latitude breeds, such as the Siberian Husky and the Greenland Sledge Dogs, can trace part of their ancestry to the now-extinct Taimyr wolf lineage. All that from a tiny piece of rib.
"The power of DNA can provide direct evidence that a Siberian Husky you see walking down the street shares ancestry with a wolf that roamed Northern Siberia 35,000 years ago," Dr. Skoglund says.
"To put that in perspective, this wolf lived just a few thousand years after Neanderthals disappeared from Europe and modern humans started populating Europe and Asia."
