Where Did Dogs Come From? cover

Where Did Dogs Come From?

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INVENTING THE DOG, CANIS FAMILIARIS
It once seemed as if the dog was a triumphant early human invention, our first domesticated animal many thousands of years ago, a deliberate product of ancient Homo sap ingenuity that has done us proud down through the millenia.
But now it appears as if dogs may not be evidence of paleolithic human cleverness after all. Perhaps, new research argues, the incipient dog was a genetic accident that we stumbled upon. Maybe dogs are just mutant wolves with a genetically based developmental disorder that we simply seized on and exploited.
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Where Did Dogs Come From?

It once seemed as if the dog was a triumphant early human invention, our first domesticated animal many thousands of years ago, a deliberate product of ancient Homo sap ingenuity that has done us proud down through the millenia.

But now it appears as if dogs may not be evidence of paleolithic human cleverness after all. Perhaps, new research argues, the incipient dog was a genetic accident that we stumbled upon. Maybe dogs are just mutant wolves with a genetically based developmental disorder that we simply seized on and exploited.

Photo by Robert Larsson on Unsplash

In humans, that genetically based developmental disorder features behavior known as hypersociability. Extreme friendliness and a naively trusting nature are well-known doggy traits, but they are also traits of people with Williams syndrome (aka Williams-Beuren syndrome).

People with the syndrome also experience developmental problems, mental disability, cardiovascular abnormalities, and a characteristic facial appearance, especially in childhood, sometimes described as “pixielike.”

Williams syndrome has been traced to losses and other variations in a chunk of human chromosome 7 that contains a couple dozen genes. The analogous area is on dog chromosome 6, and it features assorted DNA insertions, deletions and duplications in both dogs and wolves. “People with Williams-Beuren also show great variation in this region, and the variation is thought to affect the severity of the disease and people’s personalities,” according to Elizabeth Pennisi at Science.

The researchers compared 18 dogs with 10 captive hand-raised wolves. Hypersocial dogs had more DNA disruptions in the relevant chromosome area than the tame but less sociable wolves, the researchers report in Science Advances. Note, however, that this was a (relatively) small study. Commentators, though largely enthusiastic about the results, pointed that out, and called for–wait for it–more research.

In particular disruption of the gene that codes for a master regulator protein called GIF21 was associated with the most social dogs. A relative lack of changes in that gene seems to lead to less sociability.

Photo by freestocks.org on Unsplash

In mice, mutations in that gene are also associated with mouse hypersociality. Variations in two other genes in the region also linked to sociability in dogs.

Personality traits like friendliness are probably shaped by hundreds or thousands of genes, but these three genes appeared to play a surprisingly large role in controlling social behavior, said Nala Rogers at InsideScience. “We may have bred a behavioral syndrome into a companion animal,” first author Bridgett von Holdt told Carrie Arnold at National Geographic.

The study included a test of the strength of human-canid relationships that also worked as a kind of intelligence test, possibly an inadvertent one. As described by Dan Robitzski at Inverse, the dogs and wolves were challenged by being given a piece of summer sausage in a box they had to open.

If a human was seated quietly nearby, dogs tended to pay attention to the human, not the treat box, whereas the tame wolves tended to focus on the box task rather than the person. If no human was nearby, the wolves opened the box relatively easily. The dogs had a harder time obtaining the treat.

The moral of this story: Compared to wolves, dogs may be sweet-tempered and loving. But–let’s be frank here–they are also not so bright. That’s actually common in domestication. We breed our domestic animals to be stupid and docile. Dogs included.

Photo by Asique Alam on Unsplash

Just a few weeks ago I wrote here at On Science Blogs about genetic evidence supporting the idea that the domestic cat is not a human invention either. Cats, it appears, owe their enormous evolutionary success to having exploited Homo sap by domesticating themselves.

Likewise, the dog-wolf findings are a big boost to the self-domestication theory of dog evolution, evolutionary anthropologist Brian Hare told Ashley Yeager at Science News.

“This is another piece of the puzzle suggesting that humans did not create dogs intentionally, but instead wolves that were friendliest toward humans were at an evolutionary advantage as our two species began to interact.”