by Bryan Sykes
There is no trace of any cluster X sequences in Siberia or Alaska, and only a single example in China. But when the researchers looked the other way, toward Europe, they found plenty of genetic matches. I had often come across cluster X in my work on European mitochondrial DNA, and even recruited it to be among the Seven Daughters of Eve, as the descendants of Xenia, whose name begins with the cluster letter. Could this be, as the authors of the first paper on cluster X in America suggested, genetic evidence of a European origin for at least some of the first Americans?2 The radical suggestion was made in 1998, only two years after the discovery of the remains of a nine-thousand-year-old skeleton with, to some eyes, European features at Kennewick, Washington State. It was a discovery that, as we shall see, ignited an ugly and racially tinged argument about Native American origins.
I have reexamined the detail of the Ojibwa sequences and compared them with the now extensive European data to make a close comparison between the two. None of the Ojibwa sequences is exactly the same as their European cousins in the clan of Xenia, but they are not far off. The Ojibwa sequences do have their own mutations that are not seen in European Xenias, for instance the variant at 213, but the basic Xenia motif of 189 223 278 is there in both the Ojibwa and Europe. In fact one of the southeastern Ojibwa is a very close match indeed, with only a single change, at position 193, when compared with several Europeans.
Taken at face value, and remembering that unlike the other Native American mitochondrial clusters, X is not found in Siberia and eastern Asia, the evidence from the Ojibwa certainly suggests to me that they may well have a European origin. The difficulty is that this conclusion flies in the face of everything we think we know about Native American origins. Perhaps because of this, the enthusiasm for an early European arrival based on the evidence of cluster X waned among geneticists when the European and American sequences were found to be rather different in detail. But in my view that is only to be expected after a long period of isolation. The most recent genetic date estimate for cluster X in America is 15,800 years, so even with the inherent uncertainties of genetic dating, this is comparable with the age of other Native American clusters. Wherever it came from, from this evidence cluster X has been in America for a very long time. A European origin for cluster X raises all sorts of other questions.
The first of these is pretty obvious: If the ancestors of cluster X Ojibwa came from Europe rather than Asia, how did they get there? Second, as cluster X is only a minor cluster in Europe, averaging 5 percent, would it not be very strange that it was an ancestor from this clan who came to America rather than one of the others? But these paradoxes are no more difficult to explain than the alternative—that cluster X came from Asia. Here we would be asked to believe that members of cluster X joined with others in the journey from Siberia and Alaska, even though there are no signs of that cluster in northeast Asia today. While it is conceivable that cluster X became extinct in Asia at some point after the ancestors of Native Americans had left, it doesn’t seem very likely to me. Either way there are big problems in coming up with an explanation.
Although we have a genetic date for Native American cluster X that is in the same range as the other four clusters, is there any direct evidence for its early presence in America, which would at least establish the cluster as one of the genuine founders? For this we need to look to the rather sparse evidence from DNA recovered from ancient human remains. As we already know, archaeological sites containing human remains are few and far between in America, and of these only a handful have yielded credibly ancient DNA sequences.
So far the most productive site to have surrendered the DNA of its ancient occupants is a burial mound at Norris Farms in central Illinois, overlooking the Illinois River valley. The name of the site comes from the corporation that owned the land on which the mound was discovered and immediately excavated in 1984. The grave goods identified the site as a burial ground for the Oneota, who had evidently used it for only a short time and comparatively recently. Carbon dating showed that the Norris Farms site is only about seven hundred years old, predating the arrival of the first French explorers to reach that part of America by only three hundred years. Although this was a dry site, and so not protected by anaerobic waterlogging, it was slightly alkaline, which helped to preserve the bones in good condition. And, as scientists from the University of Pennsylvania discovered, the DNA was in good shape, too. To the credit of the investigators, DNA was recovered from 108 of the 260 excavated skeletons, mainly from the rib bones.3
I have had a close look at the published Norris Farm sequences, and although they are from a comparatively recent site, it was reassuring to find that twenty-three of the twenty-five different mDNA sequences recovered from the bones were easily assigned to one of the four basic American clusters. That is not to say that all the sequences had been seen before in living Native Americans. About half had not, but they shared the core characteristics and could be placed in clusters A–D without any difficulty. That left two sequences that did not belong to the classic American clusters. One sequence had the motif 189 270, which is very common in Europe and lies at the heart of cluster U5 (the clan of Ursula, another of the Seven Daughters of Eve). The mitochondrial cluster that makes up this clan is more than forty thousand years old in Europe, and its arrival there coincides with the first appearance of anatomically modern humans in the European fossil record. There is no doubting the European credentials of this clan, or of the mDNA sequence recovered from the remains excavated at Norris Farms.
The other sequence that does not fit with the four American clusters was recovered from two other skeletons from the site, and has the core motif of cluster X plus two other mutations, at 227 and 357. While it is conceivable that the Ursula sequence is the result of contamination of the sample by DNA from a modern European, the same explanation is unlikely for the cluster X sequence from Norris Farms. First, it was found in two separate individuals, and second, it does not exactly match any modern Europeans. From this I think we can be confident that cluster X was in America at the time of Norris Farms, well before Europeans arrived in large numbers.
The ancient DNA evidence for an earlier arrival of cluster X rests on material recovered from a very unusual site at Windover, Florida. Windover lies near the Indian River lagoon in Brevard County, not far from Titusville and about twenty five miles from the NASA launch complex at Cape Canaveral. Windover came to light, as so often, just by chance when a digger operator, who had been hired to build a new road across the pond for a housing development, saw human skulls looking back at him from his bucket. He reported this, and after the sheriff had taken a look at them and declared that they were not recent burials, the developer, to his credit, halted construction and even helped to fund the archaeological excavation. One of the first tasks was to find a carbon date for the remains, which came back at eight thousand years.
Eight thousand years ago Windover was a woody marsh that was used as a regular burial site by early Indians. What makes this site exceptional is that while most bogs are acidic, the pH at Windover is comparatively alkaline, thanks to the buffering effect of high concentrations of calcium and magnesium carbonates that have leached out of a layer of snail shells lying beneath the bottom of the pond. Even weak acid destroys both DNA itself and the bone mineral that protects it, which is why bodies recovered from acid peat bogs resemble empty leather sacks. The skin is intact but the bones have dissolved, and so has the DNA. Windover was excavated in the mid 1980s, and a total of 177 bodies recovered along with carved bone and wood artifacts. About half of the bodies still had intact skulls, which, when opened, revealed a dark sticky mess. Examined under a microscope, the amorphous goo was unmistakably and very surprisingly identified as the remains of human brain. The preservation was so spectacular because the bodies, which had been laid to rest in a flexed position under about three feet of water, remained in a permanently waterlogged, anaerobic, and alkaline environment. Whether or not the Windover bodies were de
liberately placed to maximize their preservation, the unusual conditions not only preserved the DNA but also stopped bacterial and fungal decay in its tracks.
I have also had a close look at the Windover data. Unlike the Norris Farms sequences, which are overwhelmingly drawn from the four known Native American clusters, the Windover sequences are highly variable and contain only one that is anywhere near a Native American sequence in cluster A.4 The rest either have no matches that I can find or they are European, so I think considerable doubt surrounds the reliability of these data. Nonetheless one of them has the core cluster X sequence motif of 223 278, which if genuine, would put a lower limit of eight thousand years on the antiquity of the cluster in America. Even though the investigators were first-rate scientists, these sequences were recovered in the very early days of ancient DNA research, before anyone appreciated the magnitude of the contamination issues. Now that techniques have improved a great deal, it would, in my view, be well worth having another look at Windover. If cluster X sequences were found along with the other familiar Native American clusters, as at Norris Farms, this would be sure evidence that the clan was in America at least eight thousand years ago and, if the genetic date for the cluster of 15,800 years is to be taken seriously, considerably earlier.
At that time the Great Ice Age was near its maximum, so how could cluster X have reached America from Europe? If it were possible for cluster B to travel by boat around the margins of the Pacific about then, could the same be true of the Atlantic? Unlike the Pacific, there is no continuous, or almost continuous, land coastline to follow. However, in the depths of the last Ice Age and again during the thirteen-hundred-year-long Younger Dryas “cold snap” that ended just over eleven thousand years ago, much of the North Atlantic was frozen solid. A voyage around the virtual coastline of sea ice that coated the North Atlantic at the time does not seem completely out of the question. Then as now the ice was home to seals and other mammals, and fish were abundant. The leads in the pack ice could have given shelter from the worst of the storms and the northern summer would mean that much of the journey could be undertaken in daylight. In many ways a sea voyage around the ice coast of the North Atlantic would be not so very different from the conditions experienced by the ancestors of cluster B Americans on their voyages around the Pacific. As we always tend to underestimate the resilience and achievements of our ancestors, I think it just might have been possible.
Such a voyage was completed by the adventurer and novelist Tim Severin in 1976, when, with a crew of three, he left the west coast of Ireland in a hide-covered curragh and eventually arrived in Newfoundland. Earlier, in 1970, Thor Heyerdahl left the coast of Morocco, in North Africa, in the reed boat Ra II and reached Barbados. Both of these heroic voyages show that a transatlantic crossing is possible using only primitive craft, but like Heyerdahl’s earlier expedition in Kon-Tiki, designed to demonstrate that Polynesia could have been settled from South America. But just because such a feat is possible doesn’t prove that it actually happened. And for Kon-Tiki and the origin of the Polynesians, we know from the genetics that it did not.5
A sea voyage can also introduce a narrow genetic bottleneck. Only the people who get on the boat and survive the journey will leave descendants. You can see this effect very clearly in the Pacific, where the whole indigenous population of Polynesia appears to descend from just three women, who could very well have fitted onto a single craft at some point in the voyage. If something similar were to have happened in the early transatlantic ancestors in cluster X, this would help to explain why it is only this comparatively rare European cluster that reached America. A single boat with one woman in the clan of Xenia on board would have been sufficient. Any men who accompanied her would leave no mDNA trace.
The notion of a European origin for Native Americans is not new. During the seventeenth century it was a widely held view by many early colonists, including William Penn, the founder of Pennsylvania, that they were the descendants of the ten lost tribes of Israel. These were the remnants of ancient tribes that were dispersed following the destruction of the kingdom of Israel by the Assyrians about 720 BC. The Jewish origin of Native Americans is still a central belief of Mormonism. Other theories with popular support at various times in the past have seen Native Americans being descended from Phoenicians, Egyptians, Greeks, Romans, and even the Welsh, as well as, predictably, survivors of the lost world of Atlantis.
Shortly before the identification of cluster X among the Ojibwa, a chance discovery thrust the question of a European origin for Native Americans into the headlines once again. While human remains of early Americans are extremely rare, none was greeted with greater interest than the skeleton found in the Columbia River near the town of Kennewick in southern Washington State. On the afternoon of Sunday, July 28, 1996, two college students, Will Thomas and David Deacy, were sitting on the bank of the Columbia watching the thirty-first annual Tri-Cities hydroplane races. Hydroplanes are powerful and thrilling machines whose thrust lifts the hulls out of the water, and the “boats” almost fly across the surface. Even though there are still 250 miles to go before the Columbia empties into the Pacific at Portland, Oregon, the river is easily wide enough to accommodate such speeding craft.
Thomas and Deacy had positioned themselves on the south shore near the Columbia Park Golf Course. As Thomas waded into the shallows to get a better view of the race, his foot hit something hard and round. Reaching down, he pulled it out of the water and, in his own words, “saw teeth”. It was a human skull. Not wanting to miss the afternoon’s final race, the pair hid the skull in the bushes, returning later with a bucket in which they handed their grisly find over to the police. Their first thought was that the young men had stumbled on the victim of a fatal accident, or even a murder, and so they notified the local coroner. This is very reminiscent of the discovery of the “Iceman” in the Italian Alps in 1991, where the body was at first mistaken for that of a missing climber and its five-thousand-year-old antiquity was not recognized until much later.
Unsurprisingly the find was not covered in the U.S. papers, with the nation’s attention on the pipe-bomb that exploded at the Summer Olympics in Atlanta the day before. Very little else of any lasting significance happened on July 28, 1996. The American papers reported a neighborhood shooting in Anaheim, California, a rousing “we must all pull together” speech by President Clinton, the conviction of a manufacturer for supplying substandard bolts for the space shuttle, and the publication of a new book by a New York Observer columnist. All but the last are long forgotten. The author was Candace Bushnell, and the book was Sex and the City, which has little, if any, genetic significance to the story unfolding on the banks of the Columbia River.
Sensing that this was no ordinary skull, the Kennewick coroner called in an anthropologist, James Chatters, who made the first excavation of the riverbank and recovered, over the course of the next few weeks, an almost complete skeleton. Its ancient pedigree was soon confirmed when Chatters found a stone spear point embedded in the hip. A more precise age for the remains of “Kennewick Man,” as he was immediately dubbed, came from radiocarbon dating that returned a date of 9,300 years.6 This was two thousand years younger than Clovis, but still a very old human by American standards. But what really catapulted Kennewick Man to a find of national and then international importance was a comment made by Chatters himself at a news conference. He claimed that the skull did not physically resemble any modern Native American. Instead Chatters said he thought that it looked much more like a European skull.
That comment, even though later denied by Chatters himself, immediately ignited a furor that threatened to undermine the widely accepted view that it was the ancestors of today’s Native Americans who were the first people to settle the continent. The European connection was only enhanced by a facial reconstruction of Kennewick Man, which bore an uncanny resemblance to the English actor Patrick Stewart, best known internationally as Star Trek’s Jean-Luc Picard, commander of the s
tarship Enterprise and successor to the legendary captain James T. Kirk.
To some the notion that America had already been reached from Europe thousands of years before Columbus was seductive. A few European Americans latched on to Kennewick Man as if he were one of their own ancestors who had discovered America. If this were true, then what did that say about Native American assumptions of priority that, after all, were the basis of land claims? The reasoning was perverted, of course, because even if some Europeans had arrived in America thousands of years ago, which I think they may well have done, they would have been rapidly subsumed, to be counted among the ancestors of today’s indigenous people.
There ensued a vociferous custody battle for the remains, for surely whoever owned the body owned the myth. First in were the Asatru Folk Assembly, a quasi-religious group of Norwegian Americans based in Nevada City, California, and an offshoot of the Viking Brotherhood. They petitioned the U.S. District Court in Portland, Oregon, to prevent the remains being handed to local Native Americans for burial. At about the same time eight anthropologists began a separate court action to prevent the remains being reburied, at least until a proper scientific investigation had been completed. The first Native Americans to stake a claim to the remains were the Umatilla, who wanted to rebury the remains according to tribal tradition.
