Modern Dogs Carry Wolf DNA from Recent Interbreeding

Most modern dog breeds have small amounts of wolf ancestry from interbreeding that occurred long after the domestication of dogs. According to a study published on November 24 in the journal PNAS, this wolf DNA does not stem from the initial divergence of dogs and wolves over 20,000 years ago, but from more recent interbreeding in the last few thousand years.

Researchers, including co-authors Logan Kistler from the Smithsonian National Museum of Natural History and Audrey Lin from the American Museum of Natural History, analyzed the genomes of nearly 2,700 dogs and wolves, encompassing 146 ancient dogs and wolves, 1,872 modern dogs, and about 300 village dogs.

They discovered that at least 264 modern dog breeds carry wolf ancestry from mating that occurred approximately 900 dog generations ago, roughly 2,600 years ago. The study found that while most modern dogs possess between zero and 5% wolf ancestry, certain breeds, like Czechoslovakian wolfdogs and Saarloos wolfdogs, can have up to 40% wolf ancestry.

This finding challenges prior beliefs that significant wolf DNA would preclude a dog from being classified as such. The research indicated that certain traits in dogs might correlate with their wolf ancestry, such as size and personality.

Breeds with lower wolf ancestry were often described as friendly, easy to train, or lively, while those with higher wolf DNA were noted to be more suspicious of strangers, independent, and dignified. Interestingly, every tested village dog contained wolf DNA, which may have conferred survival advantages in harsh environments, with specific wolf genes linked to olfactory receptors.

These genetic insights suggest that the intermixing of dog and wolf DNA has played a significant role in shaping the characteristics we see in modern dog breeds today. The findings underscore the ongoing genetic compatibility between dogs and wolves and point to a more complex history of domestication than previously understood.