Study Reveals Wolf DNA in Two-Thirds of Dog Breeds

A new study reveals that nearly two-thirds of modern dog breeds carry detectable traces of wolf DNA from interbreeding that occurred thousands of years after dogs were first domesticated, challenging previous understandings of canine evolution.

Researchers from the American Museum of Natural History in New York City and the Smithsonian National Museum of Natural History in Washington, D.C., analyzed genomes from nearly 2,700 dogs and wolves spanning the Late Pleistocene era to the present. Their findings, published on November 24 in the Proceedings of the National Academy of Sciences, show that this wolf ancestry stems from gene flow around 2,600 years ago, on average, rather than remnants from the initial split between dogs and wolves more than 20,000 years ago. The study included 146 ancient dogs and wolves, 1,872 modern dogs across 264 breeds, and about 300 village dogs that live near human settlements but are not pets.

The wolf DNA appears in varying amounts, typically between zero and 5 percent of a breed's genome, though intentionally bred wolfdogs like the Czechoslovakian wolfdog and Saarloos wolfdog show up to 40 percent from 20th-century crosses. Among breeds with...