The way we associate certain behavioral traits with certain breeds can be a huge factor in our relationships with dogs, from parents with toddlers and family-friendly labradors to couch potatoes and their sleepy greyhound sidekicks. A fascinating new study has provided compelling evidence that all is not what it seems when it comes to such stereotypes, demonstrating that the genetic reasons for different behavioral traits came thousands of years before the advent of modern-day dog breeds.

While the divergence of dogs from wolves dates back as far as 15,000 years, it was only in the 1800s that humans began selecting their companions based on certain physical and cosmetic traits we associated with modern breeds. These continue to be seen as reliable indicators of a dog’s temperament and behavior, with some breeds perceived to be easily trainable, affectionate, or highly active, for example.

Researchers at MIT, Harvard University and UMass Chan Medical School sought to fill what they see as a gap in our understanding of this relationship, pointing to a lack of genetic studies linking behaviors to ancestry. To investigate, they analyzed genome sequences from more than 2,000 dogs and matched the data with 200,000 survey answers from owners on their pet’s behaviors and physical traits, covering 78 different breeds.

This revealed that behavioral traits were influenced by a combination of environmental factors and a dog’s genetics, but modern breed classification plays only a small part. The team identified 11 unique regions in the dog genome that were strongly tied to behavior, and found that not one of them was specifically associated with any particular modern-day breed. In fact, the team concluded that a breed’s contribution to a dog’s behavior was negligible, at around nine percent.

“While genetics plays a role in the personality of any individual dog, the specific dog breed is not a good predictor of those traits,” said study senior author Elinor Karlsson. “A dog’s personality and behavior are shaped by many genes as well as their life experiences. This makes them difficult traits to select for through breeding.”

Certain behaviors were more strongly associated with other factors than breed. For example, age was found to be a better predictor of how likely a dog was to play with its toys, while a dog’s sex was found to be a better predictor of whether they lifted they leg to urinate. The scientists were also unable to find behaviors that were exclusive to any one breed. Labradors, for example, have the lowest tendency to howl but eight percent of owners still reported the behavior.

“The majority of behaviors that we think of as characteristics of specific modern dog breeds have most likely come about from thousands of years of evolution from wolf to wild canine to domesticated dog, and finally to modern breeds,” said Karlsson. “These heritable traits predate our concept of modern dog breeds by thousands of years. Each breed inherited the genetic variation carried by those ancient dogs, but not always at exactly the same frequencies. Today, those differences show up as differences in personality and behavior seen in some, but not all, dogs from a breed.”

Interestingly, the study also suggests there is little difference in certain behaviors between mixed-breed and pure-breed dogs. While biddability, or the way they respond to human direction, was more likely to correlate with breed, when it came to things like human sociability and how likely they were to be frightened, breed was almost irrelevant.

“For the most part, pure breeds are only subtly different from other dogs,” Karlsson said. “Although friendliness is the trait we commonly associate with golden retrievers, what we found is that the defining criteria of a golden retriever – what makes a golden retriever a golden retriever – are its physical characteristics, the shape of its ears, the color and quality of its fur, its size; not whether it is friendly. A golden retriever is only marginally more likely to be more friendly than a mixed-breed or another purebred dog, such as a Dachshund.”

The research was published in the journal Science. 

Source: Broad Institute