America Before
Page 14
Seeking clarification, I contacted Professor Willerslev directly at the University of Copenhagen on March 2, 2018, and asked what in his data had led him and his coauthors to conclude that the gene flow bringing the Australasian signal to the Amazon had occurred after the initial peopling of the Americas. I also asked why they favored Aleutian islanders as the likely vector and whether it was not counterintuitive to propose such an extreme northern source for this gene flow. If a northern source had indeed been involved, I argued, then:
wouldn’t we expect to see a cline in the signal from strongest in the north, nearest the putative source, to weakest in the faraway south and particularly in remote South American regions like the Amazon? But my understanding of the data is that if there is a cline at all it is in the opposite direction—i.e., from strongest in the south to weakest in the north. Am I understanding correctly and if so how do you explain this counterintuitive cline? Are we to imagine Aleutians or Athabascans island-hopping and coasting down the entire Pacific coast of North America, absolutely not intermingling with anyone else or leaving any DNA traces along the way, until they arrive (presumably) at some point on the Pacific coast of South America whence they strike inland for the Amazon?17
Professor Willerslev replied:
When you talk about a cline in contemporary data you assume peoples have stayed in the same place since the Pleistocene. We do not know that. Therefore I don’t think it’s a particularly good argument. A lot of stuff can happen over tens of thousands of years in regard to distribution of peoples. In principle the signature in the north could have been lost by replacement. We simply don’t know.18
“Dear Eske,” I responded (happily we had agreed to switch to first-name terms):
I take your point, absolutely, on all of this. And I certainly don’t imagine that peoples have stayed in the same places since the Ice Age. It’s part of the essence of being human, I think, to move around, migrate, and explore. Still, will I be misrepresenting the facts if I were to state in my book, with reference specifically to present-day populations, that a cline of the Australasian signal is evident with a stronger signal in South America, particularly the Amazon, than anywhere in North America? And further, again with reference specifically to present-day populations, would I be misrepresenting the facts to say that the Australasian signal is stronger amongst the Surui than it is amongst the Aleutians and Athabascans and that the Surui’s affinity to East Asians, Oceanians, and Denisovans is stronger than that of the Inuit?19
“No!” Eske replied, “I would not call it a cline.20… It’s strongest in the Surui but stronger in Aleutians than in Athabascans … but these groups also contain more East Asian so it may simply reflect just that. The Denisovan signal is not stronger in the Surui than in the others (to my knowledge).”21
In summary, therefore, taking into account all of the above, the situation seems to be that the Denisovan signal remains at a constant and fairly low level throughout present-day indigenous populations so far sequenced in both North and South America.22 The Australasian signal, by contrast, is definitely and notably much stronger among populations in the Amazon, such as the Surui, and much weaker among other Native Americans such as the Arhuaco (of non-Amazonian northern Colombia), the Wayuu (of non-Amazonian northern Venezuela), the Purepecha (of Mexico), and the Ojibwa, Cree, and Algonquin of north and northeast North America. While never reaching the high levels found among Amazonian populations, the signal among Aleutian Islanders and Athabascans is relatively stronger than in other Native North American groups and relatively stronger in Aleutian Islanders than it is in Athabascans—though Raghavan and Willerslev warn in their Science paper that the Aleutian Islander data must be interpreted with some caution since it “is heavily masked owing to recent admixture with Europeans.”23
“THE MOST PARSIMONIOUS SOLUTION …”
I NEXT REMINDED ESKE OF Skoglund and Reich’s papers. In these, as the reader will recall, the authors contemplate the “formal possibility”24 that the Australasian signal might reflect direct settlement in the Amazon by an Australasian-related population “that would thus have penetrated deep inside the Americas without mixing with the main ancestral lineage of present-day Native Americans.”25 My question to Professor Willerslev, therefore, was whether there was anything in the genetic data that he was aware of that would effectively refute the notion of direct settlement.
His reply got straight to the point:
Currently no one has a good explanation of the Australo-Melanesian signal. All that is put forward as possible explanations are purely speculative. So whether it’s an old or a later event is unknown. What we do know is that it’s present in some Native American groups particularly from Brazil. We also know it has to be pre-Columbian. We also know that it’s not present in any of the ancient skeletons genome sequenced so far. Possible explanations can be: 1) It comes in after the initial peopling of the Americas e.g. by costal migrations that do not leave much trace behind in contemporary populations (e.g. they move quickly), or that we just haven’t sequenced the populations in North America that hold the signal; 2) it’s an old migration through Beringia before Native Americans but then it’s strange they leave no signals in the ancient skeletons sequenced so far; 3) it’s a structured initial Native American population moving south into the Americas of which some carry the signal but again then it’s strange that there is no evidence of admixture between the two groups; 4) someone holding this signal comes into the Americas not through Beringia but crossing into South America across the Ocean. Based purely on the genetic data this is the most parsimonious explanation but it does not make practical sense; 5) Finally it’s a possibility that the signal is a methodical artefact. That the methods are not behaving as we think they should do.26
Apart from point 5, which is above my pay grade to assess, it was refreshing to encounter such a straightforward admission that no good explanation has yet been offered for the Australo-Melanesian signal, and such willingness to consider a wide range of possibilities. Since I was already leaning toward the view that the signal is mysterious and might bear witness to a crossing of the Pacific Ocean followed by the settlement in the Amazon of a relatively small group, my eyes were naturally drawn to Eske’s point 4. “Based purely on the genetic data,” and invoking the parsimony principle (whereby the simplest scientific explanation that fits the evidence is preferred), it looked very much as if this leading figure in the study of ancient genetics agreed with me! Where he and I parted company, however, was over the possibility that anybody could have made an oceanic crossing of thousands of kilometers during the Stone Age. For Eske such a proposition simply didn’t make practical sense.
I sent him a follow-up mail to ask if he based this conclusion “on the archaeological consensus that our Upper Palaeolithic and early Holocene ancestors were incapable of undertaking long trans-oceanic voyages?”27
He replied, “In regard to crossing the Pacific. I’m not saying it did not happen but there is no evidence suggesting that humans were capable of such a journey until quite late in history (Polynesian expansion). It’s a possibility and I’m open to the idea but there’s not much evidence supporting it except going for the most parsimonious solution of the genetic data.”28
So here again is a refreshing openness of mind so rarely seen among archaeologists. The best fit for the genetic data does indeed appear to be a transpacific voyage (or voyages) to South America by a group (or groups) of settlers carrying Australo-Melanesian genes. However, on the matter of the practicality of anyone undertaking transpacific voyages in the Stone Age, which has to do primarily with the level of technology attributed to our ancestors at that time, Professor Willerslev accepts, and builds into his own reasoning, the mainstream archaeological consensus that “there is no evidence suggesting that humans were capable of such a journey until quite late in history.”
He is not to be blamed for doing so, since it is normal in the sciences for an expert in one field to trust and rely upon the conclusions o
f experts in other fields. Quite possibly Professor Willerslev is not aware—why should he be?—of how little like a science archaeology really is and how often the mainstream archaeological consensus has proved, after suppressing dissenting opinions for decades, to have been fundamentally wrong all along. Recent examples include the hasty and forced addition of more than 5,000 years to the previously accepted chronology for the earliest megalithic sites after the discovery of 11,600-year-old Gobekli Tepe in Turkey,29 the collapse of “Clovis First,” and the comprehensive debunking of the long-held belief that the Neanderthals were incapable of art.30 Clearly, the mainstream archaeological consensus is not always right in what it agrees upon and it may well turn out that it is not right on the matter of grand oceanic voyages during the Ice Age. Indeed, rather than being ruled out on the basis of a priori assumptions, perhaps that strange Australo-Melanesian genetic signal in the Amazon is part of the proof that such voyages must indeed have occurred.
Then there’s the matter of the role of the Denisovans in all this. We know from the evidence of Denisova Cave itself that their technology—while undoubtedly “Stone Age”—was far ahead of its time and in some ways much more akin to the Neolithic than to the Upper Paleolithic. We know that they could make sea crossings and that they ranged over a vast area, at least from the Altai Mountains in the west to Australo-Melanesia in the east. Last but not least, we know that their DNA survives most strongly today in people of Australo-Melanesian descent, and there’s informed speculation that Australo-Melanesia may have been their original homeland.
It’s strange, and evocative, that the mystery of the Denisovans and the mystery of the Australo-Melanesian genetic signal in the Amazon should collide in this way, and all the more so because, as Eske Willerslev makes clear, there’s no especially strong Denisovan element in the signal. Perhaps further research will provide us with a higher-resolution picture, but from the data presently in hand it looks like the gene flow to the Amazon involved a population of Australo-Melanesians who had undergone little or no mixing with Denisovans. For such a people to have existed in the very area where the genetic evidence suggests the Denisovans were most strongly congregated is itself somewhat mysterious and suggests some kind of selective process at work.
In previous books, in particular Fingerprints of the Gods and Underworld, I have given extensive consideration to the intriguing phenomenon of ancient maps that show the world as it looked during the last Ice Age and do so, moreover, with stunning longitudinal and latitudinal accuracy and with the use of complex spherical trigonometry. Though it would be superfluous to reproduce here evidence that I have already presented in such detail elsewhere, I include an appendix—appendix 2—that gives some indication of the richness and the significance of this overlooked material.
However many times by however many hands they have been copied and recopied down the ages, it is my contention that these anomalous maps can be traced back to lost source documents that could only have originated with a civilization at least advanced enough to have explored the world, and to have mapped and measured it, when it was still in the grip of the Ice Age. A civilization capable of such feats must, at the very least, have had its own adepts in the techniques of boat-building, sailing, navigating, cartography, and geometry—none of these being among the skills that archaeologists are normally willing to attribute to Ice Age hunter-gatherers.
It is not inconceivable, however, if such a hypothetical civilization had existed, that it might have sponsored “outreach programs” to the hunter-gatherers who also lived in the world at that time, just as our own twenty-first-century technological civilization has “outreach programs” to hunter-gatherer tribes in the Amazon rainforest, the jungles of New Guinea, and the Namibian desert today—anthropologists, aid workers, resettlement experts, and so on and so forth. It’s even conceivable that a hypothetical lost civilization of the Ice Age could have had “resettlement experts” of its own who were interested in the outcomes that might follow from physically removing people from one area—such as Melanesia, for example—and resettling them in far-off places like South America. If a global cataclysm were to loom, threatening the annihilation of the civilization, such “outreach” initiatives might even have been accelerated to prepare hunter-gatherer populations to serve as refuges for the survivors.
This is all pure speculation, of course, but at least it’s in good company. As Eske concedes, all of the explanations—including his own—that have so far been offered to account for the presence of Australasian DNA in the Amazon are “purely speculative.”
And the mystery continues to deepen. In November 2018, two major new studies were published, one in the journal Cell, coauthored by Cosimo Posth, David Reich, and others, and the second in Science, coauthored by Eske Willerslev, J. Victor Moreno-Mayar, David Meltzer, and others.31 These new studies found Australasian DNA already present in skeletal remains from Lagoa Santa, Brazil, dated to 10,400 years ago, and confirmed the suspicion of the researchers that the anomalous genetic signal must have reached South America in the “Late Pleistocene”32—that is, near the end of the last Ice Age.
“How did it get there?” wonders geneticist J. Victor Moreno-Mayar, immediately answering his own question as follows: “We have no idea.” Similarly, David J. Meltzer expressed amazement at the most peculiar character of the signal, so clearly present in South America yet “somehow leaping over all North America in a single bound.”33
For the purposes of my own quest, however, that anomalous, unexplained signal had the effect of opening up a new and fruitful avenue of inquiry. With the archetypally North American Clovis culture now known to have South American genetic roots, it was becoming increasingly obvious that to explore the mysteries of one half of the megacontinent I could not be oblivious to what had happened in the other half.
My focus would remain on North America, to which we’ll return in part 5, but I had a strong intuition that I might miss an important piece of the puzzle if I failed to investigate the Amazon first.
I resented the intuition, which felt like a diversion, but it was so insistent that ultimately I could not ignore it.
GHOST CITIES OF THE AMAZON
IN MY QUEST FOR THE traces of a lost civilization of prehistoric antiquity, the Amazon rainforest at first seemed to have little to offer. Without that teasing, tantalizing Australasian DNA signal I probably wouldn’t have given it a second thought. But the signal was there, it was real, it was hugely anomalous, and it cried out for a deeper inquiry.
Along with much of the rest of the Americas, the Amazon entered European consciousness in the sixteenth century—the century of conquest. It was not a primary target. Mexico and Peru were hit first, their armies conquered, their wealth pillaged. Then rumors began to circulate of exotic civilizations rich in gold hidden in the jungles beyond the Andes Mountains. The greed of the Spaniards was aroused and in February 1541 Francisco de Orellana and Gonzalo Pizarro (the latter the brother of Francisco Pizarro, the conqueror of Peru) struck east from the city of Quito in Ecuador on a journey into the unknown.
Their mission was nothing less than to find the fabled El Dorado in the remote interior of South America and to loot the vast wealth they expected to find piled up there. In this they failed but in the grander scheme of things they succeeded mightily, for their expedition left us with the earliest surviving eyewitness account of the Amazon—unfortunately not of the pre-Columbian Amazon, which would have been ideal, but of the Amazon so soon after contact that it remained, effectively, in its pre-Columbian state. As such, it has much to tell us about the lost prehistory of the Americas.
At the head of a force of more than 200 Spanish soldiers, Orellana and Pizarro descended from the Andes. Hacking their way through increasingly dense and difficult jungle and fighting multiple engagements with hostile tribes, they eventually reached the banks of the Coca River, a tributary of the Napo River that is, in turn, an important tributary of the great and majestic Amazon itself. The terrain
made further overland travel almost impossible and, far from finding and reveling in the supposedly limitless riches of El Dorado, the conquistadors were by now depleted by illness and weak with hunger. Their solution was to build a fair-sized boat, which they named the San Pedro. In it, on Pizarro’s orders, Orellana then embarked with a force of 50 men to seek out and raid local villages for food.
The agreement was that Orellana would return within 12 days with whatever supplies he could gather. Unfortunately, however, the Amazon River system hadn’t been consulted when the plan was made, and the San Pedro was swept downstream at such a rate that very soon it was hundreds of miles away and the prospect of a return against the powerful currents was most uninviting. Besides, even if Orellana’s force had been able to row the rough-and-ready craft upstream again there was no guarantee that they would ever find their way back to Pizarro through the maze of braided river channels in which one opening looked very much like the next.
They decided, therefore, to press on and, in the process, became the first Europeans ever to navigate the entire length of the Amazon River and to cross the full width of South America from west to east. This was barely 20 years after the Spanish brought smallpox to the “New World”—another first!—and the great pandemics that were to depopulate the Americas had not yet penetrated deeply (if at all) into the remote fastness of the Amazon jungle. The pale horse of death would very soon follow, but Orellana’s adventure took place at just about the last time that the cultures and civilizations that had thrived and prospered in the rainforest for thousands of years could ever be seen in something approaching their original form and context.
For that reason we are fortunate that Orellana and his murderous gang of mercenaries—often starving, often having to fight for their lives—were accompanied on this desperate voyage by Brother Gaspar de Carvajal, a literate and sensitive Dominican friar who kept a journal throughout. In it he describes himself as “a man to whom God chose to give a part in such a strange and hitherto never experienced voyage of discovery, such as this one which I shall relate from here on.”1