Genetic study challenges dog breed stereotypes
The American Kennel Club website outlines the ideal shape and temperament of 204 dog breeds, from the Affenpinscher (“loyal, curious, and notoriously fun”) to the Yorkshire Terrier (“feisty, courageous, and sometimes bossy”). The idea that certain breeds reliably exhibit distinct behaviors is embedded in dog shows, obedience training, and canine DNA testing, not to mention laws targeting breeds known to be prone to aggression.
Yet a detailed new study of dog behavior and genetics suggests that breed is actually of little value in anticipating an individual animal’s behavior or behavior.
After collecting extensive data from the owners of more than 18,000 dogs and sequencing the DNA of more than 2,100 of these pets, the researchers found surprisingly few links between breed and most behavioral traits.
Yes, owners of Labrador Retrievers and Golden Retrievers were slightly more likely to rate their puppies in the top 25% for “human sociability” than the owner of a randomly selected dog. And yes, dogs of hunting breeds were more likely to score higher in terms of “submissiveness,” or the ease with which they respond to human commands. But such associations were neither strong nor consistent.
Indeed, breed explained no more than 9% of behavioral variation in the dogs in the study, said study co-author Elinor Karlsson, a geneticist at the University’s Chan Medical School. from Massachusetts. A dog’s age and sex were often much better predictors of its behavior, and for some traits, including aggression, breed made no difference.
The results were published Thursday in the journal Science.
Each of the nearly 1 billion dogs currently prancing around the planet belongs to the same species – Canis familiaris. They separated from wolves around 10,000 years ago, which wasn’t long enough for them to accumulate that much genetic diversity. (Mammalian species typically evolve over hundreds of thousands of years.)
The concept of the modern dog breed was invented only about 160 years ago, in what the authors call “a blink of an eye in evolutionary history.” Only a few genetic differences are responsible for the striking variations we see in the shape and appearance of dogs.
Physical traits are strongly inherited; behavioral traits, less. These are governed by a complex mix of genetic and environmental factors in which race plays only a small, often insignificant role.
“A dog’s appearance won’t really tell you what a dog looks like,” said Marjie Alonso, executive director of the International Assn. of Animal Behavior Consultants and co-author of the study.
The team created an open database, Darwin’s Ark, to collect information about individual dogs. Owners were asked to answer over 100 questions about their dog’s appearance, behaviors and personality.
The result was a dataset that well reflected the companion dog population in the United States. Nearly half (49.2%) of participants described their dogs as purebred, with the proportion of breeds represented roughly matching dog ownership in the United States.
Purebred dog owners tend to describe their pets’ behavior in ways that fit breed stereotypes, the authors wrote. This raised the possibility that owners’ ratings were influenced – consciously or not – by the reputation of their dog’s breed.
Fortunately, the other dogs in the study were pooches whose ambiguous ancestry left their owners relatively free of any preconceptions about their past or behavior. They served as a sort of control group.
Researchers found that golden retriever owners tended to say their pets weren’t afraid of strangers, a description that fits the breed’s outgoing reputation. However, pooch owners with golden retriever ancestry were no more likely to describe their pets as unafraid of strangers than pooch owners without golden retriever DNA.
Similarly, Labrador Retriever owners tended to say their pets were social with humans, consistent with the stereotype that the breed is friendly and outgoing. But pooch owners with a Labrador retriever in their bloodlines were no more likely to call their dogs social around humans than pooch owners without that heritage.
If breed were a strong predictor of behavior, it stands to reason that the traits of those breeds would have manifested to some degree among pooches with those breeds’ DNA.
Even among purebred dogs, genetics was a much more reliable predictor of a dog’s appearance than its behavior.
“Physical traits are super hereditary,” Karlsson said. Yet when it comes to behavior, “race is a very poor predictor. It is not an accurate way to predict the behavior of any particular dog.
But there were patterns in certain traits like submissiveness and a dog’s propensity to grab and bite toys, she added.
Border collies, for example, tend to fetch more than the average dog. Choosing a border collie as a pet can increase your chances of getting a compliant animal, but it doesn’t guarantee that the specific dog you bring home will be naturally inclined to follow your commands.
In the millennia before the Victorian obsession with dog herding began, humans distinguished dogs mainly by the tasks they did best. Some puppies were good at herding, others at hunting or guarding. A now-extinct type known as a “tournebroche”, or kitchen dog, was bred to run on a kind of dog-sized hamster wheel that turned roasting spits above the flames, said Katherine Grier, a retired University of Delaware history professor and author of the book “Pets in America: A History.”
In “The Invention of the Modern Dog: Breed and Blood in Victorian Britain”, authors Michael Worboys, Julie-Marie Strange and Neil Pemberton compared the difference between dogs before and after breeding in the colors of a rainbow. sky compared to a paint book. fries. Initially, there were a few large types of dogs with a lot of overlap between them. Breeding has taken this barking rainbow and broken it down into isolated, clearly defined units.
The American Kennel Club maintains the largest registry of purebred dogs in the United States, along with detailed descriptions for each breed standard, including personality traits. (The chow chow is “dignified, brilliant, earnest”; the Chihuahua is “charming, graceful, sassy.”)
The club said it believed the data from the study was strong, but disagreed with the authors’ conclusions.
“Racial behavior was not created with the formation of races 100 years ago. It was created based on selected working behaviors over centuries – and before the separation of individual races,” said chief veterinarian, Dr. Jerry Klein, in a statement, “Therefore, attempting to separate individual breeds based on behavior would not be successful without separating them into selected ancestral populations of sheepdogs, gundogs, etc. .”
Historians of dog breeding counter that breeders’ preference for specific physical traits over the years has often come at the expense of original behaviors. Dog breed is largely defined by an animal’s appearance, and “when you breed for looks, you can lose behaviors,” Grier said.
When it comes to canine behavior, genes “have an effect, but it’s less than the effect that genes have on physical traits,” said Danika Bannasch, an animal genetics specialist at UC Davis who has no not participated in the study. “This is the largest-scale study of genes and behavior of its kind and is sure to make a lot of people stop and think about dogs a little differently.”