Last week, there was a big development in the long-running, bitter, complicated battle over a 9,000-year-old set of bones known variously as "Kennewick Man" or "The Ancient One," depending on whom you ask.
The U.S. Army Corps of Engineers confirmed that the ancient bearer of the bones is genetically linked to modern-day Native Americans. Now, under federal law, a group of tribes that has been fighting to rebury him will almost certainly get to do so.
It also means that scientists will probably never get another chance to study him, though ancient human remains from North America are incredibly rare, and forensic technology gets better all the time.
"It's the chafe between science and spirituality," writes Kevin Taylor at Indian Country Today, "between people who say the remains have so much to tell us about the ancient human past that they should remain available for research, versus people who feel a kinship with the ancient bones and say they should be reburied to show proper reverence for the dead."
There's a history to bitter tensions of this sort. Take the recent fight between native Hawaiian protesters and scientists who wanted to erect a telescope on Mauna Kea, a dormant volcanoconsidered sacred by some and "the best location in the world to observe the stars and study the origins of our universe" by others.
None of these clashes exists in a vacuum; they often come on the heels of decades, if not centuries, of genocide and erasure aimed at indigenous peoples and their ways of life. And so an object of scientific interest, be it a bone or a mountain, can come to stand for an entire civilization.
Some say scientists need to rethink their whole approach to culturally sensitive research. Others say the unfettered pursuit of knowledge ought to trump belief; if the faithful always got their way, we'd still think the Earth was flat. Who gets to decide? The twists and turns in the story of Kennewick Man — which has been told before, and well — suggest there's no easy answer, of course, but certainly provide an incredible case study for the future of this debate.
A forensic mystery, or a moot point?
Archaeologists hoped that Kennewick Man could help settle one of the greatest mysteries in the story of human migration: How did Homo sapiens make it to the Americas? Kevin P. Casey/AP hide caption
Archaeologists hoped that Kennewick Man could help settle one of the greatest mysteries in the story of human migration: How did Homo sapiens make it to the Americas?Kevin P. Casey/AP
The fight has been raging for 20 years, ever since a couple of college kids stumbled — literally — across a human skull while wading in a river in Washington state. They thought they'd found a murder victim, and flagged down a nearby cop, who called in a local expert. Instead, they had discovered some of the oldest, most complete human remains ever dug up in North America.
Archaeologists dubbed the skeleton Kennewick Man, after the place he was found, and hoped his bones could help settle one of the greatest mysteries in the story of human migration: how did Homo sapiens, originating in Africa, end up in the Americas?
The dominant theory was that humans trekked here on foot around 13,000 years ago, during the Ice Age, when seas were lower and a land bridge temporarily connected Siberia and Alaska. But other evidence suggests humans were already living on this continent well before that particular pathway was possible.
So which was it? Did humans walk here, or somehow — incredible to imagine — paddle? Was there one wave of migration, or more? A study of Kennewick Man's bones could reveal what he ate, what he drank, how he hunted, and, of course, his DNA — all clues that could ultimately tell the story of where he, and his forebears, came from and how they got here.
But a group of Native American tribes considered The Ancient One, as they call him, a direct tribal ancestor — and they didn't need science to explain how people ended up here. "From our oral histories, we know that our people have been part of this land since the beginning of time," a leader of the Umatilla tribe wrote in a statement at the time. "We do not believe that our people migrated here from another continent, as the scientists do."
Working together, five tribes demanded that The Ancient One's remains not be poked or prodded in the name of science, and instead be promptly reburied in accordance with tribal custom — and under the Native American Graves Protection and Repatriation Act. That federal law, passed in 1990, requires certain Native American artifacts and remains to be handed over to culturally affiliated tribes or provable descendants.
"The tribes had good reason to be sensitive," writesSmithsonian Magazine's Douglas Preston. "The early history of museum collecting of Native American remains is replete with horror stories. In the 19th century, anthropologists and collectors looted fresh Native American graves and burial platforms, dug up corpses and even decapitated dead Indians lying on the field of battle and shipped the heads to Washington for study. Until NAGPRA, museums were filled with American Indian remains acquired without regard for the feelings and religious beliefs of native people."
But for these bones to fall under the protection of NAGPRA, there had to be proof of a connection between the remains and the people fighting to reclaim them today. The scientists said no such connection existed. The tribal leaders insisted it did; they could feel it in their bones.
That question ended up spawning an unprecedented legal and ethical battle in which prominent archaeologists and anthropologists would sue the U.S. government for the chance to study the bones. Femur bones would go missing under unexplained circumstances. Bitter arguments would be pitched over the migration patterns and feeding habits of sea lions, the curvature and racial implications of cheekbones, the validity of oral tradition as courtroom evidence.
Eventually, the scientists did get a legally approved (though very brief and highly constricted) look at Kennewick Man, and what they learned is truly amazing. Based on the shape of his skull and other features, they theorized that he or his forebears may have been Asian coastal seafarers. They may have journeyed by boat along the south Alaskan shoreline and ultimately all the way down the Americas, hugging the coast and living off kelp, fish, sea lions and the like.
This is the "coastal migration" theory of the peopling of the Americas, which suggests that a wave, or waves, of people traveled and lived along the Pacific coast long before other travelers chased herds of tasty mastodons and mammoths across a land bridge into Alaska.
They also learned a tremendous amount about what Kennewick Man's life may have been like. Here's more from Preston:
"Kennewick Man spent a lot of time holding something in front of him while forcibly raising and lowering it; the researchers theorize he was hurling a spear downward into the water, as seal hunters do. His leg bones suggest he often waded in shallow rapids, and he had bone growths consistent with 'surfer's ear,' caused by frequent immersion in cold water. His knee joints suggest he often squatted on his heels. ... Many years before Kennewick Man's death, a heavy blow to his chest broke six ribs. Because he used his right hand to throw spears, five broken ribs on his right side never knitted together. This man was one tough dude."
Conflict, or collaboration?
As of last week, it's likely that this tough dude is headed back to the earth. University of Chicago scientists confirmed another study, from last year, showing that Kennewick Man's DNA has genetic similarities to those of modern-day Colville tribal members. Now, members of the Colville tribe and four others say they'll work together to complete the repatriation — or reburial — process, and the government has shown zero interest in standing in their way.
But while scientists may never get another chance to study these remains, even as biomolecular science is "advancing so rapidly that within five to ten years it may be possible to know what diseases Kennewick Man suffered from and what caused his death," writes Preston, the story of Kennewick Man raises all sorts of questions as to how researchers might avoid antagonizing local cultures to begin with — or whether they should have to try.
One of the scientists involved in revealing a genetic connection between Kennewick Man and living Native Americans invited members of the five tribes into the lab, where they put on body suits and entered a "clean room" to pay their respects to The Ancient One. In the wake of Kennewick, scientists have been reflecting on ways to work with indigenous communities when these kinds of conflicts come up:
"Many other researchers are taking a similar approach. [Dennis O'Rourke, a biological anthropologist at the University of Utah in Salt Lake City] says that there is no one-size-fits-all strategy to working with native communities. He finds some of the North American Arctic groups he works with eager to contribute to his research, others are less so; and their opinions shift over time.
" 'We really have to change the top-down approach, where we come to people and say "these are our research questions and you should participate, because — SCIENCE," ' says Jennifer Raff, an anthropological geneticist at the University of Texas at Austin."
Other scientists say there's a real danger in altering scientific methods to accommodate religious belief. Elizabeth Weiss, an anthropologist at San Jose State, outlined impediments to her own work in a 2001 paper on the Kennewick controversy, and argued that regulations like NAGPRA require far too little evidence proving a cultural connection to modern-day native communities. She also suggested that such regulations — which increased around the world in the wake of NAGPRA — can have a chilling effect on scientific research:
"Consider having dedicated a large part of one's life to unearthing the materials that are now being examined. Even casts and other important works — such as videotapes, photos, and excavation records — are in increasing danger of confiscation. Some scientists have expressed fear that their federal grants would be in jeopardy if they objected too openly to current policies. Under such circumstances, most scientists do not even begin 'high-risk' projects. Finds that could threaten Native American origin beliefs are especially likely to be targeted. Defendants could become embroiled for years in expensive lawsuits that neither they nor their institutions can afford ...
"The politics of bone gathering in Africa are notorious ... and one shudders to imagine what might happen if activists could convince modern Africans to claim early human skeletons as their ancestors, so that they too could be reburied."
As this saga draws to a close, perhaps only one thing is certain. Wherever science, ethics and history collide, easy answers don't exist. The distinction between pioneering researcher and grave robber can depend entirely on whom you ask. But there's one more story worth telling here, that of another very old pile of North American bones that got a whisper of the attention that Kennewick Man has gotten, because the raging fight over what to do with them simply never got started. From Nature:
"Just weeks before Kennewick Man's remains were discovered, researchers working in Alaska discovered a 10,000-year-old human skeleton. They notified local tribes and quickly came to an agreement that allowed them to excavate and study the remains and keep the tribes involved in the research. 'You don't really hear so much about the good cases,' says Raff."
The skeleton of Kennewick Man was inadvertently discovered in July of 1996 in shallow water along the Columbia River shoreline outside Kennewick, Washington state, USA. On several visits to the locality over the following month, some 300 bone elements and fragments were collected, ultimately comprising ∼90% of an adult male human skeleton3. The initial assessment of this individual was that he was a historic-period Euro-American, based largely on his apparently “Caucasoid-like”3 cranium, along with a few artefacts found nearby (later proved not to be associated with the skeletal remains). However, radiocarbon dating subsequently put the age of the skeleton in the Early Holocene1. The claim that Kennewick Man was anatomically distinct from modern Native Americans in general, and in particular from those tribes inhabiting northwest North America4, sparked a legal battle over the disposition of the skeletal remains. Five tribes who inhabit that region requested the remains be returned to them for reburial under the Native American Graves Protection and Repatriation Act (NAGPRA). The US Army Corps of Engineers, which manages the land where Kennewick Man was found, announced their intent to do so. That in turn prompted a lawsuit to block the repatriation2,5, and generated considerable scientific controversy as to Kennewick Man’s ancestry and affinities (for example, refs 3, 6, 7, 8, 9). The lawsuit ultimately (in 2004) resulted in a judicial ruling in favour of a detailed study of the skeletal remains, the results of which were recently published2.
These studies provide important details on, for example, Kennewick Man’s life history, refine his antiquity to 8,358 ± 21 14C years bp or to within a two sigma range of 8,400–8,690 calibrated years bp (based on 90% marine diet, and 750 year marine reservoir correction), and demonstrate that the body had been intentionally buried and had eroded out shortly before discovery2. They also include anatomical and morphometric analyses, which confirm earlier studies that Kennewick Man resembles circumpacific populations, particularly the Ainu and Polynesians2,10; that he has certain “European-like morphological” traits2; and that he is anatomically distinct from modern Native Americans2. These results are interpreted as indicating that Kennewick Man was a descendant of a population that migrated earlier than, and independently of, the population(s) that gave rise to modern Native Americans2.
However, those recent studies did not include DNA analysis. Herein we present the genome sequence of Kennewick Man in order to resolve his ancestry and affinities with modern Native Americans. There were several prior efforts to recover genetic material from Kennewick Man11, but none were successful.
We obtained ∼1 × coverage of the genome, from 200 mg of metacarpal bone specimen (Supplementary Information 1) using previously published methods12,13. The endogenous DNA content was between 0.4% and 1.4% for double-stranded and single-stranded libraries, respectively (Supplementary Information 2). Average fragment length was 53.6 base pairs (bp) and the sample exhibited damage patterns typical of ancient DNA, with excessive deamination of cytosine towards the ends of the fragments (Supplementary Information 2). Similarly, patterns of DNA decay agree with published expectations14, and display an estimated molecular half-life corresponding to 3,670 years for 100-bp molecules (Supplementary Information 3). The mitochondrial genome was sequenced to ∼71× coverage and is placed at the root of haplogroup X2a (Extended Data Fig. 1 and Supplementary Information 2), and the Y-chromosome haplogroup is Q-M3 (Extended Data Fig. 2 and Supplementary Information 5); both uniparental lineages are found almost exclusively among contemporary Native Americans15,16. We used the X chromosome to conservatively estimate contamination to be 2.5%, which is within the normal range obtained observed in genomic data from ancient human remains17, and we further show this contamination to be of European origin (Supplementary Information 4).
We compiled an autosomal reference data set consisting of published SNP array data18,19,20,21,22,23 as well as new data generated from one of the claimant tribes, the Colville (Supplementary Information 10). Due to high levels of recent admixture in many Native American populations, we masked European ancestry from the Native Americans (Supplementary Information 6). No masking was done on the Kennewick Man. When we compare Kennewick Man with the worldwide panel of populations, a clear genetic similarity to Native Americans is observed both in principal components analysis (PCA) and using f3-outgroup statistics (Fig. 1a, b). In particular, we can reject the hypothesis that Kennewick Man is more closely related to Ainu or Polynesians than he is to Native Americans, as seen in a D-statistic-based test where no trees of the type ((CHB,Ainu/Polynesian),(X,Karitiana)) with X being Kennewick Man, the Clovis age Anzick-1 child (ref. 12) or a modern Native American genome are rejected (Extended Data Fig. 3). Model-based clustering using ADMIXTURE24 shows that Kennewick Man has ancestry proportions most similar to those of other Northern Native Americans (Fig. 1c and Supplementary Information 7), especially the Colville, Ojibwa, and Algonquin. Considering the Americas only, f3-outgroup and D-statistic based analyses show that Kennewick Man, like the Anzick-1 child, shares a high degree of ancestry with Native Americans from Central and South America, and that Kennewick Man also groups with geographically close tribes including the Colville (Fig. 2a, b and Extended Data Fig. 4). Despite this similarity, Anzick-1 and Kennewick Man have dissimilar genetic affinities to contemporary Native Americans. In particular, we find that Anzick-1 is more closely related to Central/Southern Native Americans than is Kennewick Man (Extended Data Fig. 5). The pattern observed in Kennewick Man is mirrored in the Colville, who also show a high affinity with Southern populations (Fig. 2c), but are most closely related to a neighbouring population in the data set (Stswecem’c; Extended Data Fig. 4c). This is in contrast to other populations such as the Chipewyan, who are more closely related to Northern Native Americans rather than to Central/Southern Native Americans in all comparisons (Fig. 2d and Extended Data Fig. 4d).
Our results are in agreement with a basal divergence of Northern and Central/Southern Native American lineages as suggested from the analysis of the Anzick-1 genome12. However, the genetic affinities of Kennewick Man reveal additional complexity in the population history of the Northern lineage. The finding that Kennewick is more closely related to Southern than many Northern Native Americans (Extended Data Fig. 4) suggests the presence of an additional Northern lineage that diverged from the common ancestral population of Anzick-1 and Southern Native Americans (Fig. 3). This branch would include both Colville and other tribes of the Pacific Northwest such as the Stswecem’c, who also appear symmetric to Kennewick with Southern Native Americans (Extended Data Fig. 4). We also find evidence for additional gene flow into the Pacific Northwest related to Asian populations (Extended Data Fig. 5), which is likely to post-date Kennewick Man. We note that this gene flow could originate from within the Americas, for example in association with the migration of paleo-Eskimos or Inuit ancestors within the past 5,000 years25, or the gene flow could be post-colonial19.
We used a likelihood ratio test to test for direct ancestry of Kennewick Man for two members of the Colville tribe who show no evidence of recent European admixture. This test allows us to determine if the patterns of allele frequencies in the Colville and Kennewick Man are compatible with direct ancestry of the Colville from the population to which Kennewick Man belonged, without any additional gene flow. As a comparison we also included analyses of four other Native Americans with high quality genomes: two Northern Athabascan individuals from Canada25 and two Karitiana individuals from Brazil12,13. Although the test rejects the null hypothesis of direct ancestry with no subsequent gene flow in all cases, it only does so very weakly for the Colville tribe members (Table 1 and Supplementary Information 8). These findings can be explained as: (1) the Colville individuals are direct descendants of the population to which Kennewick Man belonged, but subsequently received some relatively minor gene flow from other American populations within the last ∼8,500 years, in agreement with our findings above; (2) the Colville individuals descend from a population that ∼8,500 years was slightly diverged from the population which Kennewick Man belonged or (3) a combination of both.
It has been asserted that “…cranial morphology provides as much insight into population structure and affinity as genetic data”2. However, although recent and previous craniometric analyses have consistently concluded that Kennewick Man is unlike modern Native Americans, they disagree regarding his closest population affinities, the cause of the apparent differences between Kennewick Man and modern Native Americans, and whether the differences are historically important (for example, represent an earlier, separate migration to the Americas), or simply represent intra-population variation2,3,7,10,26,27,28. These inconsistencies are probably owing to the difficulties in assigning a single individual when comparing to population-mean data, without explicitly taking into account within-population variation. Reanalysis of W. W. Howells’ worldwide modern human craniometric data set29 (Supplementary Information 9) shows that biological population affinities of individual specimens cannot be resolved with any statistical certainty. Although our individual-based craniometric analyses confirm that Kennewick Man tends to be more similar to Polynesian and Ainu peoples than to Native Americans, Kennewick Man’s pattern of craniometric affinity falls well within the range of affinity patterns evaluated for individual Native Americans (Supplementary Information 9). For example, the Arikara from North Dakota (the Native American tribe representing the geographically closest population in Howells’ data set to Kennewick), exhibit with high frequency closest affinities with Polynesians (Supplementary Information 9). Yet, the Arikara have typical Native-American mitochondrial DNA haplogroups30, as does Kennewick Man. We conclude that the currently available number of independent phenetic markers is too small, and within-population craniometric variation too large, to permit reliable reconstruction of the biological population affinities of Kennewick Man.
In contrast, block bootstrap results from the autosomal DNA data are highly statistically significant (Extended Data Fig. 3), showing stronger association of the Kennewick man with Native Americans than with any other continental group. We also observe that the autosomal DNA, mitochondrial DNA and Y chromosome data all consistently show that Kennewick Man is directly related to contemporary Native Americans, and thus show genetic continuity within the Americas over at least the past 8,000 years. Identifying which modern Native American groups are most closely related to Kennewick Man is not possible at this time as our comparative DNA database of modern peoples is limited, particularly for Native-American groups in the United States. However, among the groups for which we have sufficient genomic data, we find that the Colville, one of the Native American groups claiming Kennewick Man as ancestral, show close affinities to that individual or at least to the population to which he belonged. Additional modern descendants could be identified as more Native American groups are sequenced. Finally, it is clear that Kennewick Man differs significantly from the Anzick-1 child who is more closely related to the modern tribes of Mesoamerica and South America12, possibly suggesting an early population structure within the Americas.