Long considered man's most faithful companion, the dog embodies in the eyes of many a clear break with its wild ancestor. However, genetics blurs this boundary. Behind the familiar barks and wet noses, an older memory remains. Wolf DNA in modern dogs reveals a more winding history than simple domestication.
A domestication more complex than we thought
The dog would have been domesticated around twenty thousand years ago from wolves which are now extinct. Research believed that crossbreeding between wolves and dogs was rare after this period, except in a few recent cases such as the Saarloos or the Czechoslovakian wolfdog.
A study published in November 2025 in the journal PNAS analyzed more than 2,600 genomes of ancient dogs, wolves and canids. It was conducted jointly by the Smithsonian Institute and the American Museum of Natural History. The results show that 64.1% of purebred dogs still carry fragments of lupine DNA. These traces come from crossings that occurred well after the first domestication. According to the researchers, these genetic exchanges date back approximately 873 generations, or a few thousand years.
The study also shows that all so-called village dogs, living freely near humans without a defined breed, carry lupine segments. According to the authors, it is likely that isolated wolves crossed paths with stray dogs, particularly in areas disturbed by human activities.
What wolf DNA reveals in today's dogs
Saarloos and Czechoslovakia logically have high levels, up to 40% of lupine DNA. But other cases are surprising. The Grand Anglo-Français tricolor, used for hunting, can carry more than 5%. Even the chihuahua, a miniature breed, contains about 0.2% lupine DNA. Audrey Lin, co-author of the study, humorously pointed this out in an article published on Science Alert, saying that it wouldn't surprise anyone with a Chihuahua at home.
These fragments are not randomly distributed in the genome. In village dogs, researchers observed a concentration of genes linked to olfactory transduction, inherited from wolves. According to the research team, this characteristic could improve their ability to detect food waste or survive in autonomous environments.
Another striking example concerns Tibetan dogs. Some have a version of the EPAS1 gene, identical to that of wolves living at high altitudes, which facilitates adaptation to low oxygen levels. This suggests an ancient and selective transmission of an advantageous lupine fragment.
When wolf genes shape dog traits
The effects are not limited to physical abilities. The researchers compared the genetic data to official breed descriptions listed by kennel clubs. Dogs with little lupine DNA are more often described as sociable, affectionate, or easy to train. Those who wear more are described as independent, vigilant or reserved.
These portraits do not describe each dog individually. However, they suggest that certain lupine fragments could influence traits present in certain lineages. These discoveries push science to review its vision of dogs. He no longer appears as the opposite of the wolf, but as a version transformed by humans. A wild side, discreet but tenacious, nevertheless seems to have survived.
With an unwavering passion for local news, Christopher leads our editorial team with integrity and dedication. With over 20 years’ experience, he is the backbone of Wouldsayso, ensuring that we stay true to our mission to inform.
