I wonder often IF dogs love us. 

Most people assume so. And here’s research on why. 

I’ll have to assume it’s true until my dog says otherwise

Somehow, dogs have evolved to like being around humans

Somehow, dogs have evolved to like being around humans. In return for their exuberant, slobbery affection, dogs have convinced us to take care of them-driving otherwise sane adults to carry around plastic baggies filled with warm poop. The rough idea is that tens of thousands of years ago, wolves probably began trailing human hunter-gatherers to scavenge their kills. Friendlier wolves may have been fed extra scraps, or more frightening wolves might have been killed-and over time, this group of wolves eventually evolved into dogs.

The genetic blueprint underlying this personality shift is still a mystery, however. So Bridgett vonHoldt, an evolutionary geneticist at Princeton University, and Monique Udell, at Oregon State University, led a team of scientists to find out what sets dogs apart from wolves. Using a combination of genetic sequencing and behavioral tests, they pinpointed a couple genetic differences that seem to track with friendliness, according to a study published today in the journal Science Advances.

“This may be one of the first studies to ever identify the specific genetic variants that were important for turning wolves into dogs,” Adam Boyko, a dog geneticist at Cornell University, who wasn’t involved in the study, told The Verge in an email. “Really exciting stuff.” Still, he adds, to be certain the genetic variations vonHoldt’s team identified really are linked to dogs’ friendliness, he’d want to see the results validated in a bigger, and more diverse set of dogs.

The dogs spent more time gazing adoringly at the person than at the puzzle box

The scientists started out by testing how 18 dogs and 10 wolves behave around people. For one test, the dogs and the wolves were tasked with extracting a nice, thick piece of summer sausage from a puzzle box either in front of a person, or alone. The wolves clobbered the dogs in both trials, and could stay focused even when a human was nearby. But the dogs couldn’t; they spent more time gazing adoringly at the person than at the puzzle box.

“What they’re really doing is just obsessively staring at this human,” vonHoldt says. “They don’t really care about the task, they’re just interested in the person.” Another test measured how many times a dog or a wolf sidled up next to a human sitting nearby. Overall, the dogs spent much more time close to the person than the wolves did.

In an earlier study, vonHoldt identified a gene that’s mutated more often in dogs than wolves-possibly because of domestication. This gene also corresponds to one in humans that’s among several deleted in people born with a condition called Williams-Beuren syndrome, or WBS. People with WBS tend to be especially social and friendly, which made the researchers suspect that these genes might be important for friendliness both in people and in dogs.

They’re tantalizing clues in the mystery of dog domestication

So vonHoldt and her team decided to start with that stretch of genes, plotting the behavioral test results against the genetic sequences. They uncovered a few mutations that appear to be linked to dogs’ sweet dispositions: two of them may interfere with the functions of the genes GTF2I and GTF2IRD1, which make proteins responsible for turning other genes on and off. Animals with these mutations appeared to pay more attention to the humans than those without, vonHoldt says.

That would make sense: earlier work showed that deleting these genes in mice makes the little rodents much friendlier. People with WBS who still have functioning versions of GTF2I and GTF2IRD1 aren’t quite as extroverted as people who don’t. In the complicated case of how genes and a dog’s environment might make it more or less friendly, today’s findings aren’t a smoking gun. But they are tantalizing clues in the mystery of dog domestication.

“The story is far from complete.”

“We’re not saying we have found the mutation that controls sociability,” vonHoldt says. There are a lot of genes in the genome that probably contribute to dogs’ demeanors-and she and her team have only investigated a fraction of them, she says. Plus, genes aren’t deterministic; whether a dog was raised in a loving or abusive home, for example, could shape how friendly it is as an adult. “The story is far from complete,” she says.

But that hasn’t stopped her from genotyping her own friendly pup. “She has a number of these mutations,” she says. “The pieces fit together.”

This article originally appeared at: https://www.theverge.com/2017/7/19/16000172/dogs-wolves-canines-genetics-evolution-domestication-love-best-friends.

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