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The Native Americans Before the Native Americans

www.palladiummag.com

The Native Americans Before the Native Americans​

In 2021, scientists radiocarbon-dated pollen found in human footprints at the White Sands National Park in New Mexico and came back with dates of greater than 20,000 years. Critics demanded more evidence, and in 2023, using new data and more advanced methods seems to have confirmed the date. Though there are still skeptics, the White Sands discovery is not the only site that dates to the Last Glacial Maximum between 20-26,000 years ago.

For decades, paleoanthropologists believed the ancestors of American natives were a Siberian tribe that came over from Asia to North America just 13,500 years ago, crossing over Beringia, a landmass exposed by sharply reduced sea levels during the last Ice Age. They called these people the Clovis Culture based on distinct spear points first discovered next to the remains of mammoths at a site in New Mexico. The paradigm posited that over 300 years these big game hunters spread across the New World, driving megafauna into extinction and eventually diversifying into the people we know today as Native Americans.

Yet, already 25 years ago, the evidence contradicting this paradigm became quite strong. There were too many sites that predated Clovis by centuries. Monte Verde in Chile, where archaeologists have been excavating since 1977, is extensively documented and is over 1000 years older than Clovis. In Mexico, Chiquihuite Cave has yielded 1900 stone artifacts, and dates were returned as early as 31-33,000 years ago, long before the Last Glacial Maximum. Being more conservative, the researchers at this site are convinced that humans were claiming it 20,000 years ago at the latest. These dates imply that this population, presumably part of the same group that was leaving footprints at White Sands National Park, arrived much earlier because the expansion of the ice sheets beginning 26,000 years ago definitively blocked the interior migration path and would have made a sea-borne route along the western periphery very difficult as glaciers pushed to the edge of the Pacific.

In 2014, geneticists discovered and sequenced the 24,000-year-old remains of a boy who died on the shores of Lake Baikal and concluded that people related to him contributed 10-15% of the ancestry of modern Europeans and 40% of the ancestry of Native Americans. In one fell swoop, earlier anthropological and genetic suspicions of connections between the two populations were explained. Then, in 2015, the same group of geneticists found that some tribes in the Amazon had ancestry which tied them more closely to Australian Aboriginals and Papuans than to Siberians! This seemed to be a crazy result, but follow-up work not only confirms its correctness, but shows that this exotic ancestry is found across the central band of South America, from the coast into the Amazon.

The latest controversial but methodologically cutting-edge models imply that humans arrived in the New World more than 30,000 years ago, long before the proto-Beringian population was even hypothesized to exist. The world we thought we knew in the 1990s turns out not to be anything close to the world that might have been. Over the last 25 years, there has been a revolution in our understanding of how the first humans arrived in the Americas and who they were. But these revelations have not illuminated the totality of the past; there still are dragons in the blank spots in our map of this surprisingly ancient New World.

Native Americans And Europeans Share Paleo-Siberian Ancestors​

Some of the more sensational arguments on the ancestry of Native Americans turn out to have fallen flat. The Solutrean hypothesis, which argued that Native Americans descended at least in part from an Ice Age European culture that flourished 20,000 years ago based on similarities between that culture’s tools and that of the Clovis people, is clearly wrong. The similarities in tool types, separated by 4000 years between the extinction of the former and the emergence of the latter, are likely just convergence, the product of the constraints in functionality and physics.

Bill Whittaker/North American spearpoints that appear to be precursors to later Clovis points
You don’t need fancy genetics to reach this conclusion. Not only do many native peoples of the New World look like they have anthropological affinities with the people of eastern Eurasia, but 20th-century physical anthropological metrics like the shape of teeth or the dimensions of the skull tended to cluster Native Americans with East Asians. Additionally, before the Norse, all the evidence points to contacts with Asia rather than the continent to North America’s east. The native peoples of the Arctic clearly have cultural connections to the indigenous tribes of far east Siberia, in particular the Chukchi.

This contact was profoundly impactful in the first millennium AD when the recurved Asian war bow arrived in Alaska in the 7th century AD over the Bering Strait, to be followed several centuries later by laminar armor familiar from medieval Japan. The New World is characterized by stark isolation, with North American civilizations at the late Neolithic and early Bronze Age stages of complexity when Eurasia was on the precipice of early modernity, but it was also permeable across the sieve of the circumpolar world.

A physical anthropologist once told me that even after more than 10,000 years, the indigenous people of the Amazon retain “Siberian proportions”—shorter legs and arms and a longer torso. In many ways, it is easier for cold-adapted people to flourish in the tropics; after all, our lineage was originally tropical, and the cultural toolkit for the cooler latitudes can simply be discarded—literally, in the case of clothes. The world of the early Amerindians was not the lush and verdant Amazon basin; it was the vast expanse of land exposed during the last Ice Age between Alaska and Siberia, Beringia. Here they arrived 20,000 years ago, likely following herds of mammoth on its north slope, on the tundra facing the Arctic, while they exploited marine resources in the south, along the seas characterized by fog and peat-bogs.

Genetic and anthropological work with blood groups and skeletal features established that the closest population to New World natives were the people of East Asia, supporting the theory promoted by geologist David Hopkins in the 1960s of a migration over a Bering land bridge. Nevertheless, simple physical inspection yielded the inference that these were not quite the same people as those of China, Korea, and Japan. Geography pointed to Siberia, but even here, the modern-day Yakut looks somewhat different from Native Americans, who often have prominent aquiline noses. Of course, aquiline noses are common in western Eurasia, suggesting possible connections with Europeans.

The answer was prefigured by paternal lineage as traced through the genealogy transmitted from father to son. By the first decade of the 21st century, it was clear that the overwhelming majority of Native American Y chromosome lineages belong to the Q haplogroup—the class of related men bracketed together as a distinct cluster with a common ancestor defined by informative mutations.

The nomenclature of Y chromosomes is alphabetic, and the closest “sibling” to Q is R, which, in the forms of R1a and R1b, is the dominant haplogroup in Europe. The Y chromosomal data points to a genetic relationship between the forefathers of Europeans and Native Americans, which remained inexplicable. More suggestively, in 2012, a new method of constructing genetic relationships that use graphs or networks instead of trees, with the gene flow represented by “edges” connecting different branches, yielded a hypothetical migration on the schematic connecting Europeans and Native Americans. Though this jumped out of the data, there was no historical paradigm to integrate the result.

Two years later, the Ma’lta boy, dating to 24,000 years ago, was the first of many finds from Siberia where ancient DNA provided the “missing link” between these two populations, one in the New World and the other at the western antipode of Eurasia. The perplexities of the past could finally find an elegant explanation.

After the expansion of modern humans into Eurasia more than 45,000 years ago, one branch of Homo sapiens related to the foragers of Pleistocene Europe continued to move eastward until their furthest outliers reached northeastern Siberia. Called “Ancient North Eurasians” (ANE) by scholars, no human population is a direct singular descendent of this group. Modern Siberians descend predominantly from later waves of migrants from East Asia, who absorbed the first modern human populations.

NaturalEarthData.com/Map of Ancient North Eurasian (ANE) dispersion.
The ancestors of Native Americans are often called, originally, “Paleo-Siberians,” a fusion of ANE and East Asians moving up from the south. Though the overall ancestry, around 65%, tilts toward East Asians, the paternal lineage is biased toward the remainder, the ANE heritage. The ANE and East Asian ancestors of Native Americans seem to have diverged from the ancestors of the populations that later contributed to modern Siberians and Europeans between 20-25,000 years ago.

Walking From Siberia to Alaska, Sailing to America​

As sea levels dropped 400 feet lower than today during the Last Glacial Maximum, a vast tundra opened up between the eastern tip of Siberia and northern Alaska. This now sunken land was a prime megafauna habitat. Despite its northern location, this dry ecosystem was not glaciated and likely supported large human populations that followed the migration of mammoths. In contrast, the area to the south—the exposed land that is today the northern Bering Strait—was dominated by peat bogs, and any forager populations would likely have had to rely on marine resources. Rather than a single tribe with a single culture, the early Beringians were likely adapted to numerous local ecologies.

And yet, these people did not move east and into North America; the Last Glacial Maximum resulted in the expansion of the Cordilleran and Laurentide ice sheets in western and eastern North America, closing a potential path through the interior of North America. The ice age closed as many paths as it opened. The best data indicates that these two ice sheets did not open a corridor until 14,000 years ago, post-dating evidence of human occupation in Monte Verde in Chile by 500 years.

U.S. National Park Service/Map of the ancient Beringia region.
Rather than indefatigable mammoth hunters killing their way through the interior, the Beringians likely arrived in the New World along the western fringe of North America, hugging the coast and hopping across islands as marine foragers. Island hopping was feasible beginning 17,000 years ago, resulting in pockets of human occupation along the southern Alaskan coast while the sea levels began to rise as the Ice Age abated.

While genetic evidence strongly points to a bottleneck that began around 20,000 years ago, the archaeological evidence strongly points to the opening of a viable path southward into the Americas after 17,000 years ago. This 3000 years or so is sometimes termed the “Beringian standstill,” when the ancestors of the Native Americans occupied ecologically favored territory east of Siberia but were blocked by ice sheets from moving further east into North America.

Over these more than one hundred generations, a homogeneous genetic population emerged in Beringia, isolated from populations to the east. The genetic influences evidenced in eastern Siberians and the Inuit, who arrived to the Arctic long after the Ice Age, are not present in Native Americans because their Beringian ancestors were sealed off from Eurasia, first by the extreme conditions of the Last Glacial Maximum and then rising sea levels, which broke the connection between the Americas and Eurasia.

Looking at the genetic network of haplogroup Q, more than 90% of full-blooded Native American males, a massive demographic expansion seems to have occurred around 14,000 years ago, just before the rise of the Clovis people, along with a later expansion in South America 12,000 years ago. This, seemingly, was most of the story.

The Na-Dene people of western North America, most prominent of whom are the Navajo tribe, have more East Asian ancestry, and observers have long-observed their more East Asian features, while the Paleo-Eskimos and the Thule Culture of the modern Inuit date to the period after 3000 BC. Though the source and timing of the Na-Dene migration has not been entirely established, ancient DNA makes it seem likely that they arrived after the end of the Ice Age, but before the Paleo-Eskimos.

A fusion between two Siberian groups more than 20,000 years ago gave Native Americans ties to populations of western and southern Eurasia. A later migration eastward was halted by glaciers, until a final radiation began to occur 15,000 years ago, likely through the Pacific route, and then a switch to big game mammoth-hunting again with the Clovis people. Finally, secondary supplementary migrations from Siberia during the Holocene point to the long-term periodic exchanges across the Bering Strait that continued after the sea levels rose. But this was not to be the end of what genetics told us.