A new study could help us better understand our canine companions. National Institutes of Health scientists say they have discovered some of the ways genes can influence the behaviors of certain breeds, such as herding dogs.
For about two decades, a team led by Elaine Ostrander at the National Human Genome Research Institute has been working on the Dog Genome Project. The ultimate goal of the project is to understand how genetics affect everything from a dog’s susceptibility to disease to their body shape. In their new study, published On Thursday at Cell, his team delved into the genetic underpinnings of dog behavior.
“Our study analyzed the genomes of thousands of dogs from hundreds of breeds and populations around the world to uncover the genetic basis for behavioral diversity in modern dogs,” Ostrander said in an email to Gizmodo. “We wanted to understand what in their genes makes herding dogs move livestock, terriers kill vermin, dogs help us hunt, etc.”
Overall, they studied the genes of more than 4,000 purebred dogs, mixed-breed pooches, semi-wild dogs, and even wild cousins of the domestic dog. Based on this analysis, they identified 10 genetically distinct lineages. The team noticed that breeds with similar behavioral traits often clustered within these lineages, such as dogs that primarily hunt using sight versus hunting dogs that rely on smell. They then cross-checked what they found with survey data from over 46,000 purebred dog owners.
From there, Ostrander said, the team “determined that each bloodline has its own unique mix of behavioral tendencies that make them good at the jobs they were originally tapped for.” Terrier breeds, for example, tend to be more enthusiastic about hunting potential prey, which makes sense, since these dogs were originally bred to hunt parasites.. Finally, the team tried to find specific genetic variations that could influence the behaviors of certain breeds, including those that affect early brain development.
“For example, among sheepdogs, a collection of uniquely behavioral breeds historically used to herd livestock, we have identified variants associated with genes controlling axon guidance, a process that lays the foundation for connectivity in the brain. that modulates complex behavioral traits,” Ostrander said. These variants, some of which have been linked to attention deficit hyperactivity disorder in humans, could help explain why sheepdogs tend to become incredibly focused when tending a herd.
While humans have domesticated many animals, dogs were probably the first. And since then they’ve become perhaps the most diverse creature, especially in the last two hundred years when intentional dog breeding became widespread (a pug looks very little like a husky, for example). Importantly, Ostrander and his team’s research also indicates that many of the genetically-based behavioral differences we now see in dogs were not created by modern breeding.
“Instead, the earliest ‘types’ of dogs likely came into prominence in different parts of the world over thousands of years as humans kept them for different purposes,” Ostrander said. “Our work shows that when humans first started classifying dogs into ‘breeds’ a few hundred years ago, they were preserving unique snapshots of the genetic diversity of dogs that existed in a certain place at a certain time, and that this genetic diversity was behaviorally relevant.”
This work is just the beginning for the Ostrander team. They plan to continue searching for specific genetic variants that determine the breed’s behaviors. The same unique approach developed for this study should also allow them to study how a dog’s genetics can influence other complex traits, including their risk for certain diseases. And just like dogs have done for us so many times in the past, what we learn from this research could one day help humans too.
“Dogs and humans get the same diseases, these diseases present in much the same way, and everything we learn about canine genetic health impacts our understanding of our own disease susceptibility,” said Ostrander.
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