This supports the idea that dogs were domesticated somewhere in China. The team calculated that the two dog dynasties split from each other between 6, and 14, years ago. But the oldest dog fossils in both western and eastern Eurasia are older than that.
Which means that when those eastern dogs migrated west into Europe, there were already dogs there. To Larson, these details only make sense if dogs were domesticated twice. Many thousands of years ago, somewhere in western Eurasia, humans domesticated grey wolves.
The same thing happened independently, far away in the east. So, at this time, there were two distinct and geographically separated groups of dogs. Along their travels, these migrants encountered the indigenous Ancient Western dogs, mated with them doggy style, presumably , and effectively replaced them.
Less than 10 percent comes from the Ancient Western dogs, which have since gone extinct. This is a bold story for Larson to endorse, not least because he himself has come down hard on other papers suggesting that cows, sheep, or other species were domesticated twice.
Everything else is once. They concluded that dogs were domesticated somewhere in Europe or western Siberia, between 18, and 32, years ago.
By comparing the full genomes of 58 modern wolves and dogs, his team has shown that dogs in southern China are the most genetically diverse in the world. They must have originated there around 33, years ago, he says, before a subset of them migrated west 18, years later. Those Ancient Western dogs might have just been wolves, he says. Or perhaps they were an even earlier group of migrants from the east. It must have happened in southern East Asia. Except, you totally can. Adam Boyko from Cornell University does, too: After studying the genes of village dogs—free-ranging mutts that live near human settlements—he argued for a single domestication in Central Asia, somewhere near India or Nepal.
And clearly, Larson does as well. Larson adds that his gene-focused peers are ignoring one crucial line of evidence—bones. If dogs originated just once, there should be a neat gradient of fossils with the oldest ones at the center of domestication and the youngest ones far away from it. Instead, archaeologists have found 15,year-old dog fossils in western Europe, 12,year-old ones in east Asia, and nothing older than 8, years in between.
A dual domestication makes more sense. But even Larson is hedging his bets. Von Holdt suspects that the gene variants in dogs inhibit their normal function, leading to the same issues seen in humans with Williams syndrome. Since evolving from a shared ancestor with wolves at least ten thousand years ago, domestic dogs have helped us find food and protected us from becoming dinner ourselves, all while providing a friendly face and wagging tail.
Read more about how dogs evolved in National Geographic magazine. In , in collaboration with Monique Udell , an animal behaviorist at Oregon State University, von Holdt searched the dog and wolf genomes and identified alterations in the WBSCR17 gene that occurred during dog domestication, results they published in Nature. Their project lay dormant until , when von Holdt and Udell secured funding to set up a new set of experiments with 18 dogs of various breeds—including dachshunds, Jack Russell terriers, and Bernese mountain dogs—and 10 wolves habituated to humans.
The scientists trained all of the animals to open a box that contained a piece of sausage. Then they asked the canines to open the box while in three separate situations: with a familiar human present; with an unfamiliar human; and alone, without a person at all. In all three scenarios, the wolves outperformed the dogs by a large margin. That margin got even larger when the dogs had to open the box in the presence of people. They Domesticated Us.
For the new study, Von Holdt conducted additional genetic analysis of the part of the genome surrounding the altered WBSCR17 gene in a larger sample of dogs and wolves. The combination of the genetic and behavioral data told von Holdt that changes to this region of the genome helped turn wolves into human-loving dogs. The University of Pennsylvania's Overall cautions that the study size was small, which limits the strength of the findings.
But she praised the strength of the genetic analysis. Thanks for reading Scientific American. Create your free account or Sign in to continue. See Subscription Options. Discover World-Changing Science.
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