How genes drive your dog’s friendly and crazy behavior

A new study may help us understand our canine companions a little better. Scientists at the National Institutes of Health say they have discovered some of the ways genes can influence the behavior of certain breeds, such as herding dogs.

For about two decades, a team led by Elaine Ostrander of 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 vulnerability to disease to its body shape. In their new study, published On Thursday in Cell, his team took a deep dive 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 in order to uncover the genetic basis for the behavioral diversity of modern dogs,” Ostrander said in an email to Gizmodo. “We wanted to understand what in their genes makes sheepdogs move cattle, terriers kill animals, dogs help us hunt, etc.”

Overall, they studied the genes of more than 4,000 purebred dogs, mixed-breed mutts, semi-wild dogs and even wild cousins ​​of the domestic dog. From this analysis, they identified 10 genetically distinct lineages. The team observed that breeds with similar behavioral traits often cluster within these lineages, such as dogs that hunt primarily by sight compared to hunting dogs that rely on scent. They then cross-referenced what they found with survey data from more than 46,000 purebred dog owners.

From there, Ostrander said, the team “determined that each lineage has its own unique mix of behavioral tendencies that make them good at the jobs they were originally kept for.” Terrier breeds, for example, tend to be more enthusiastic when chasing potential prey, which makes sense since these dogs were originally bred to chase pests.. Finally, the team sought to find specific genetic variations that might drive behaviors in certain breeds, including those that affect early brain development.

“For example, among sheepdogs, a behaviorally unique collection of breeds historically used for herding, we identified variants associated with genes that control axon guidance, a process that underlies 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 be incredibly focused while herding.

Although humans have domesticated many animals, dogs were probably the first. And since then they’ve become perhaps the most diverse creature around, especially in the last two hundred years, when intentional dog breeding was widely practiced (a pug bears very little resemblance to a husky, for example). But importantly, Ostrander and his team’s research also indicates that many of the genetically driven behavioral differences we now see in dogs were not created by modern breeding.

“Instead, the first ‘types’ of dogs probably rose to 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 began classifying dogs into ‘breeds’ hundreds of years ago, they were preserving unique snapshots of the genetic diversity of dogs that existed in a particular place at a particular time, and that this genetic diversity was relevant to behavior.”

This work is just the beginning for Ostrander’s team. They plan to continue looking for specific gene variants that drive 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 the risk of certain diseases. And just as 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, those diseases present themselves in the same way, and anything we learn about canine genetic health affects our understanding of our own susceptibility to disease,” Ostrander said.