The Complicated Science—and Conflict—Behind Identifying the First Native Americans

Genetic studies of living Native Americans and ancient remains are revising our theories about America’s first inhabitants.
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(Illustration: Public Domain)

(Illustration: Public Domain)

It seemed like a victory of science over myth when, in 2004, the United States Court of Appeals for the 9th Circuit ruled that a group of Native American tribes would not be allowed to re-bury the 8,500-year-old skeleton known as Kennewick Man. The remains had been found eight years earlier on the banks of the Columbia River in Washington state, and, based on their oral traditions, the tribes argued that Kennewick Man was one of their ancestors. Under the 1990 U.S. Native American Graves Protection and Repatriation Act, they were entitled to take possession of any ancient human remains that relate to "a tribe, people, or culture that is indigenous to the United States." But according to a group of scientists who sued to gain access to one of the most important anthropological finds in North America, Kennewick Man's unusual Caucasian features meant that he belonged to an unknown but different ancient population unrelated to contemporary Native Americans. The Court agreed with the scientists, finding that "scant or no evidence of cultural similarities between Kennewick Man and modern Indians exists." The remains would stay in the museum where they were being kept, and scientific research could go forward.

That scientific research has now proved that the Native Americans were basically right. A study of Kennewick Man's genome published a few weeks ago shows that he belonged to an ancient population closely related to present-day members of the tribes who sought to re-bury the bones. This development in the Kennewick Man story is just the latest in a series of sometimes dramatic revisions to earlier ideas about how the Americas were first settled, thanks in large part to new evidence from genetics. In fact, what the scientists found in Kennewick Man’s DNA was not especially surprising, because the findings are consistent with several other important genetic studies published over the past decade. The evidence from these studies is cracking open one of the biggest mysteries in anthropology: Who were the ancestors of today's Native Americans?

"[T]he great majority of Native American populations—from Canada to the southern tip of Chile—derive their ancestry from a homogeneous 'First American' ancestral population, presumably the one that crossed the Bering Strait more than 15,000 years ago."

Prior to these genetic studies, scientists had developed several conflicting theories about how the Western Hemisphere was first settled. Most of these theories rooted from several widely accepted ideas: First, the Americas were the last region of the world to be populated by modern humans, almost certainly less than 20,000 years ago. Those first settlers were the first humans of any kind to arrive—unlike Africa, Asia, and Europe, the Americas contain no fossils of archaic humans like Neanderthals or Homo erectus. Also, the first settlers gradually migrated from Siberia to Alaska across the Bering land bridge, which is now under water but was then a wide, fertile plain with plenty of game. Consistent with this theory, Native Americans possess unmistakable anatomical similarities to Siberians and East Asians.

Beyond these points of consensus, there has been little agreement. Thirteen-thousand-year-old stone tools, made in a consistent style called Clovis (named for the New Mexico site where they were first discovered), have been found from northern Canada to the tip of South America, leading some scientists to propose that a single wave of original settlers colonized the entire hemisphere. But later discoveries of distinct pre-Clovis artifacts and remains led to the idea that the Clovis settlers were preceded by an earlier migration. According to this idea, these so-called "Paleoamericans" were unrelated to later Native Americans and were eventually replaced by the Clovis people, from whom today's Native Americans descend. Another major theory, based on an analysis of Native American languages, is that there were three waves of migration: a first wave of Amerindians, who populated most of North and South America; a second wave of Na-Dene, who settled northern Canada and Alaska; and a third, relatively recent Eskimo-Aleut wave. Given this heated mix of competing hypotheses, it's easy to see why scientists were so eager to study Kennewick Man when his remains turned up.

Recent genetic studies based on technologies developed after the court’s Kennewick Man ruling offer a powerful new source of evidence to help resolve these disagreements. Researchers can now survey the DNA of large numbers of different Native American populations and compare them to other populations from around the world, especially Siberia and East Asia. More and more often, the DNA of living populations can be directly and extensively compared with DNA from ancient bones. One of the major casualties of these new studies is the Paleoamerican replacement idea on which the Kennewick Man ruling was based—just four years after the Court issued its ruling, one review of the field bluntly concluded that "genetic data do not support this model." Paleoamericans were not a distinct group, unrelated to the later Clovis people.

It was clearly a mistake for scientists to frame the conflict over Kennewick Man’s remains as an "epistemological conflict," which pitted the rigor of science against the mushy myths of oral traditions.

Since then, additional genetic analyses have shown that, as one key study published in 2012 put it, "the great majority of Native American populations—from Canada to the southern tip of Chile—derive their ancestry from a homogeneous 'First American' ancestral population, presumably the one that crossed the Bering Strait more than 15,000 years ago." That study, led by Harvard geneticist David Reich and one of the most exhaustive to date, included DNA surveys of 60 different living Native American and Siberian populations. The genetic data also showed that two other groups arriving from Asia after these “First Americans” contributed some DNA to members of the Eskimo-Aleut-speaking tribes in the Arctic and to the Na-Dene-speaking Native Americans in Canada. These results are somewhat consistent with the earlier three-wave theory based on linguistic analysis, but they show that coupling between original settlers and later arrivals played an important role.

Last year, a team led by the University of Copenhagen scientist Eske Willerslev published an analysis of the genome of a ~13,000 year-old infant discovered in a grave in western Montana that supports these findings. A comparison of the child’s DNA to that of living Native Americans and Siberians, as well as to ancient DNA from remains found in Siberia, led the researchers to conclude that the evidence "demonstrates that contemporary Native Americans are descendants of the first people to settle successfully in the Americas."

Given this evidence, it is really no surprise that the recent DNA analysis of Kennewick Man, also performed by Willerslev and his team, shows a close relationship with modern Native Americans. In fact, the researchers found that one of the tribes, the Washington state-based Confederated Tribes of the Colville Reservation, that claimed Kennewick Man as its own is part of a group that is especially closely related to Kennewick Man. And what about Kennewick Man’s unusual Caucasian features? Willerslev’s team reviewed the evidence and concluded that there aren’t enough distinct anatomical features “to permit a reliable reconstruction” of Kennewick Man’s relationship to present-day populations. The genetic data is much better.

Willerslev’s findings don't mean that the tribes' oral traditions about their ancestry are an accurate record of what was happening in the Americas 9,000 years ago. But it does show that researchers need to make a better argument for their studies of ancient American remains—these studies can't be justified by arguments that they have nothing to do with today's tribes. Fortunately, researchers came away from the Kennewick Man controversy recognizing that better engagement with Native Americans will advance both their research and its reception. Researchers are inviting tribes into their labs to explain the science and engaging them in discussions about how to handle ancient remains. It was clearly a mistake for scientists to frame the conflict over Kennewick Man’s remains as an "epistemological conflict," which pitted the rigor of science against the mushy myths of oral traditions. Native Americans, just like any group of people with cherished cultural and religious traditions, can value their beliefs and, at the same time, still be eager to know the science of who they are and where they come from.

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