Siberia may be long-sought site of dog domestication

doi:10.1126/science.371.6528.451

GSTDTAP > 气候变化

DOI	10.1126/science.371.6528.451
	Siberia may be long-sought site of dog domestication
	David Grimm
	2021-01-29
发表期刊	Science
出版年	2021
英文摘要	Sometime toward the end of the last ice age, a group of humans armed with stone-tipped spears stalked their prey in the bitter cold of northeastern Siberia, tracking bison and woolly mammoths across a vast, grassy landscape. Beside them ran wolflike creatures, more docile than their ancestors and remarkably willing to help their primate companions hunt down prey and drag it back to camp. These were the world's first dogs. Their descendants flowed both west and east, populating Eurasia as well as accompanying the ancestors of Native Americans as they spread into the Americas. That's the scenario laid out in a new study combining DNA data from ancient dogs and humans. The analysis, published this week in the Proceedings of the National Academy of Sciences , aims to end years of debate about where and when dogs were domesticated. It may even explain how wary wolves were transformed into faithful companions in the first place. “I love this study,” says Jennifer Raff, an anthropological geneticist at the University of Kansas, Lawrence. More genomes from ancient dogs and people will be needed to confirm the findings, she says, but already, “It's amazing to see how the dog story and the human story match up.” The research started over beers in evolutionary biologist Greger Larson's office at the University of Oxford. He was chatting with Angela Perri, a zooarchaeologist at Durham University, about a canine conundrum: the origins of ancient dogs in North America, where evidence suggests they have lived for at least 10,000 years. Archaeologist David Meltzer, visiting from Southern Methodist University, chimed in to suggest comparing ancient DNA from dogs and humans. “Dave started talking about how and when people branched out into different groups first when they were in Siberia and then after they reached North America,” Perri recalls. If dog DNA showed similar patterns, that could reveal when the dog and human stories began to match up. “We went to a giant whiteboard and started scribbling arrows in all different directions. It was a hot mess, but it spelled out the story of dog domestication.” To refine their doodling, the researchers analyzed previously sequenced mitochondrial genomes of more than 200 dogs from all over the world. The mitochondrial DNA—short sequences that are more abundant in fossils than nuclear DNA—showed that all ancient American dogs carried a genetic signature, dubbed A2b, and that they splintered into four groups about 15,000 years ago as they spread around North America. The timing and location of those splits mirror those of ancient Native American groups, the team found. All of those people descend from a group scientists call ancestral Native Americans, who arose in Siberia about 21,000 years ago. Those people must have brought dogs with them when they entered the Americas about 16,000 years ago, the team concluded. (The ancient American dogs later vanished, wiped out after Europeans came to the Americas with their own canines.) Going even deeper into the genetic past, the team found that the A2b dogs descended from a canine ancestor that lived in Siberia about 23,000 years ago. That ancestral dog probably lived with people who belonged to a genetic grouping known as the ancient north Siberians, the team speculates. The group, which appeared more than 31,000 years ago, lived in a relatively temperate part of northeastern Siberia for thousands of years, and they shared this refuge with the gray wolf, the direct ancestor of today's dogs. “These people were probably sleeping on the ground in furs, roasting fresh kills on the fire,” Meltzer says. “If you're a hungry carnivore and you smell a mammoth barbecue, you're going to check it out.” The idea fits the leading theory of dog domestication, which holds that gray wolves inched closer and closer to human campsites to scavenge food, with the least timid ones evolving over hundreds or thousands of years into the gentle pups we know today. What's more, genetic evidence suggests the ancient north Siberians mingled with the ancestral Native Americans before they migrated to the Americas. The ancient dog breeders might have traded animals to the lineage that became Native Americans, as well as to other groups of people, including those traveling farther west into Eurasia. That could explain why dogs appeared in both Europe and North America about 15,000 years ago, a puzzle that had previously sparked speculation that dogs were domesticated more than once. Instead, all dogs descend from roughly 23,000-year-old Siberian pups, the team argues. Peter Savolainen, a geneticist at the Royal Institute of Technology in Stockholm, is dismissive. He says the A2b signature that the team claims is exclusive to the Americas has been found elsewhere in the world. This invalidates the entire genetic analysis, he argues, and the new study “can't say anything” about dog domestication. But based on all she knows about ancient people in the Americas, Raff says the study's basic story “rings true.” Still, she notes, mitochondrial DNA represents only a tiny fraction of an animal's genome. “You can't fill in the full picture without nuclear DNA.”
领域	气候变化 ; 资源环境
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条目标识符	http://119.78.100.173/C666/handle/2XK7JSWQ/313981
专题	气候变化资源环境科学
推荐引用方式 GB/T 7714	David Grimm. Siberia may be long-sought site of dog domestication[J]. Science,2021.
APA	David Grimm.(2021).Siberia may be long-sought site of dog domestication.Science.
MLA	David Grimm."Siberia may be long-sought site of dog domestication".Science (2021).