Ancient dog genomics reveal prehistoric ancestry differs from wolves

An international team of scientists sequenced 27 ancient dog genomes and found that all modern dogs share a common ancestry distinct from today's wolves. 

The scientists also looked at how dog history and human history were linked over time. They compared dog genetic relationships in particular locations and ages with matching data from "17 sets of human genome-wide data."

DNA was extracted from dog remains found in museums and archeological sites in Europe, the Near East and Siberia, dating back 11,000 years. The researchers found that by the end of the Ice Age, there were at least five major dog lineages with distinct genetic histories.

Over thousands of years, these early dog lineages mixed and developed into the types of dogs we are familiar with today.

The study was led by scientists at the Francis Crick Institute, University of Oxford, University of Vienna and archaeologists from more than 10 countries. Their research paper appeared in the journal Science, Oct. 30.

Anders Bergström, lead author and post-doctoral researcher in the ancient genomics laboratory at the Crick Institute, comments in a Crick news release: “If we look back more than 4,000 or 5,000 years ago, we can see that Europe was a very diverse place when it came to dogs. Although the European dogs we see today come in such an extraordinary array of shapes and forms, genetically they derive from only a very narrow subset of the diversity that used to exist.”

The study sheds new light on the historical relationship of man and his best friend. Until now only six ancient dog and wolf genomes have been available.

The researchers were able to reconstruct the relationship of dogs and humans over time, mostly finding similarities in movement as human populations moved across geographic areas. As humans intermixed with new populations, dogs intermixed with new dog populations.

But in some cases they found the history of dogs and humans did not align, suggesting that on occasion "humans dispersed without dogs, dogs moved between human groups, or that dogs were cultural and/or economic trade commodities."

As for where the first dogs originated, the researchers state, "In our view the geographical origin of dogs remains unknown."

Are dogs domesticated wild wolves? The genetic evidence is not there today, according to the study.

The researchers found "no detectable evidence" for extensive gene flow from wolves to dogs. They speculate that perhaps "all dogs derive from a single ancient, now-extinct wolf population, or possibly multiple closely related wolf populations."

But the present research shows that there was "limited gene flow from wolves since [dog] domestication but substantial dog to wolf gene flow."

Although the study provides much new information, there are still many questions, in particular when and where dogs were first domesticated.

Ron Pinhasi, author and group leader at the University of Vienna, commented in a Crick Institute news release: "Just as ancient DNA has revolutionized the study of our own ancestors, it’s now starting to do the same for dogs and other domesticated animals. Studying our animal companions adds another layer to our understanding of human history."