For example, the sheep herding breeds were characterized by genetic variants associated with a neurodevelopmental process known as axon guidance, which helps ensure that neurons are wired together correctly. Some of these variants were specifically associated with genes that have been linked to anxiety and maternal behaviors, including pup retrieval in mice.
One hypothesis — still unproven, the scientists note — is that a sheep dog’s drive to herd is a product of the same anxiety-related neural pathway that motivates animal mothers to care for their young.
“When you watch these mice, these mothers gathering up their young, it’s just like watching a Border collie herd sheep,” Dr. Ostrander said. “And so you could throw out a hypothesis that maybe that’s the ancestral behavior that’s been co-opted.”
(Dr. Ostrander, who used to have a Border collie, has seen this herding drive firsthand. “I used to be able to bring mine to the lab and she could herd people up for lab meetings,” she said.)
Still, many of the variants that were closely associated with specific lineages did occur, at lower levels, in other lineages or even in gray wolves, suggesting that they predated the creation of modern breeds.
And just because there are differences, in aggregate, between canine lineages does not mean that breed is behavioral destiny, Dr. Karlsson noted.
“That doesn’t mean that every single retriever is going to retrieve a ball or every single herder is going to be completely different from every single retriever,” she said. “Many dogs are not going to fit what our expectations are based on their breed. And, you know, that’s totally fine, because that’s why they’re so much fun to have as pets.”