Nearly 11,000 years ago, a man died in what is now Nevada. Wrapped in a rabbit-skin blanket and reed mats, he was buried in a place called Spirit Cave.
Now scientists have recovered and analyzed his DNA, along with that of 70 other ancient people that were discovered throughout the Americas. The findings astonishing detail to a story once lost to prehistory: how and when people spread across the Western Hemisphere.
The earliest known arrivals from Asia have been divided into recognizably distinct groups, the research suggests. Some of these populations thrived, becoming the ancestors of indigenous peoples throughout the hemisphere.
But other groups died out, leaving no trace for what can be discerned in ancient DNA. Indeed, the new genetic research hints at many dramatic chapters in the peopling of the Americas that has archaeology has yet to uncover.
"Now, this is the grist for archaeologists," said Ben Potter of the University of Alaska, who was not involved in the new papers. "Holy cow, this is awesome."
Earlier studies had indicated that people were moving into the Americas at the end of the last ice age, traveling from Siberia to Alaska across a country bridge now under the Bering Sea. They spread southward, eventually reaching the tip of South America.
Until recently, geneticists could offer little insight into these fixed migrations. Five years ago, just one ancient human genome had been recovered in the Western Hemisphere: that of a 4,000-year-old man discovered in Greenland.
The latest batch of analyzes, published in three separate studies, marks a turnaround. In the past few years, researchers have recovered the genomes of 229 ancient people from teeth and bones discovered throughout the Americas.
The first, described in January by Eske Willerslev, a geneticist at the University of Copenhagen, was an 11,500-year-old girl who was found in eastern Alaska.
The second was hundreds of miles away, in western Alaska, and lived 9,000 years ago. Willerslev and his colleagues reported on Thursday in the journal Science.
The Ancient Beringians separated from the ancestors of living indigenous people in the Americas about 20,000 years ago. The new findings suggest that they are endured for several thousand years. Then they disappeared, leaving no known genetic trace in living people.
But another wave of migrants from Siberia did not stop in Alaska. They kept moving, eventually arriving at the ice age glaciers. Then they split into two branches.
One group turned and headed north, following the glaciers into Canada and back to Alaska. The other branch took a remarkable journey south.
The genetic data suggest that this group spread swiftly across much of North America and South America about 14,000 years ago. The expansion may have tasks only centuries.
"It's basically an explosion," Dr. Willerslev said.
The man from Spirit Cave in Nevada belongs to this so-called southern branch of migrants. He was closely related to a 12,700-year-old boy found on the other side of the Rocky Mountains in Montana, Dr. Willerslev also found.
But the man from Spirit Cave also turned out to be a genetic link to 10,400-year-old skeletons found in Brazil, on the other side of the Equator.
David Reich of Harvard University and his colleagues found a similar pattern in their own research, published on Thursday in the journal Cell.
They uncovered a link between the ancient Montana boy and another group of South Americans, including a 10,900-year-old skeleton in Chile. Like Dr. Willerslev's work, the kinship suggests that migrants have moved rapidly from North America to South America.
"We agree that this must be a rapid radiation," said Dr. Reich.
Starting about 9,000 years ago, both teams found, additional waves of people moved southward. Dr. Willerslev's research suggests the new arrivals mixed with older South American populations.
Dr. Reich, on the other hand, sees evidence for two waves of migrants who had lived in South America.
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The new research also shows instances of remarkable continuity, kinships that spanned thousands of years.
Dr. Willerslev and his colleagues compared to the genius of the man from the Spirit Cave to those of four sets of remains found nearby in Nevada's Lovelock Cave, who lived as recently as 600 years ago.
All of these people were closely related, his team found, despite being separated by 10,000 years of history.
A similar bond was found in the Andes. John Lindo of Emory University and his colleagues analyzed DNA from seven people who lived at high elevations between 6,800 and 1,400 years ago.
The researchers estimate that people who lived above 7,500 feet in the mountains were separated from the lowland populations between 9,200 and 8,200 years ago. Today, the mountain people still show a strong genetic link to the ancient remains.
"This is not something that you see in most other regions of the world," he said. Reich.
In 2015, Dr. Reich and his colleagues found that some people living in the Amazon carry some DNA that is most similar to those who live in Australia and New Guinea.
The researchers speculated that their ancestry included an unknown group, whom the scientists called Population Y, who made their way into the Americas.
In their new study, Dr. Reich and his colleagues found no trace of Population Y – but Dr. Willerslev's team succeeded in identifying their DNA in some of the 10,400-year-old skeletons in Brazil.
"The million-dollar question is obviously, how did this happen?" Willerslev said.
Perhaps another group of Asians entered the Americas long before the ancestors of the man from Spirit Cave and other early Native Americans. Maybe they are interbred with people in the Amazon before disappearing altogether.
Or perhaps a few of the early members of the southern branches have survived through the generations.
The new rush of genetic samples reflects an improving relationship between scientists and indigenous peoples. For decades, many tribes rejected requests for DNA from researchers.
The man from Spirit Cave, for example, was dug up by archaeologists in 1940 and stored in a museum. The local tribe, the Fallon Paiute-Shoshone, did not learn anything until 1996. For years they fought for its repatriation.
"It's utterly disrespectful," said Rochanne L. Downs, a member of the tribe's cultural committee. "If someone went into Arlington Cemetery and dug the grave or their medals, there would be an outrage."
Initially, the tribe was opposed to looking for DNA in the skeleton, because scientists would have to destroy much of it. Dr. Willerslev with the tribe and explained that he would require only a small piece of ear bone.
The tribe agreed to give him one shot at finding DNA in the Spirit Cave remains.
Dr. Willerslev's results led the Bureau of Land Management to turn over the skeleton to the tribe. They buried the man from the Spirit Cave at an undisclosed location last year.
Ms. Downs would not rule out similar studies in the future, but said that every request would require careful consideration.
"It's all going to be a case-by-case basis," she said. "The main thing is our respect for the remains."