Thursday, January 21, 2021

Earliest Evidence of Humans Living in South America

Monte Verde: Our Earliest Evidence of Humans Living in South America
By Bridget Alex November 1, 2019 

As the Ice Age began to wane, people from northeastern Asia spread to the Americas, some of the last uninhabited continents on Earth. The pioneers traveled south of mile-high ice sheets covering Canada and found vast lands, abounding with mammoth, giant sloth and other now-extinct megafauna.

This much has been known for decades. But when it comes to the details, debates have raged over precisely when and how humans populated the New World. Today, the story is beginning to take shape, thanks to well-dated archaeological sites, DNA analysis and geological work to understand when ice and sea levels permitted entry to the Americas. It’s clear that people occupied the continents by about 15,000 years ago, probably taking a route along the Pacific coast.

And one site, perhaps more than any other, helped scholars reach this conclusion: Chile’s Monte Verde. During excavations begun in the 1970s, archaeologists unearthed numerous artifacts, including remnants of 14,000-year-old huts, food scraps from megafauna and wads of masticated seaweed, likely chewed for medicinal purposes. The preservation was so exceptional, it cleared any doubt that humans had reached the New World by this time, and earned Monte Verde a place in every archaeology textbook to come.

Meanwhile, recent research on the site’s surroundings and deeper layers suggests humans inhabited this patch of South America as early as 19,000 years ago. While the claim remains controversial, it’s clear there’s still more to discover at Monte Verde.

Creekside Campsite
Buried under a peat bog, Monte Verde is near South America’s tip and about 30 miles from the Pacific in present-day Chile. Excavations began in 1976, led by archaeologist Tom Dillehay. Although no human skeletons were found, an excavated layer — radiocarbon dated to about 14,000 years ago — held clear evidence of human inhabitants, including a child-sized footprint.

At Monte Verde, the researchers discovered the ruins of a forager campsite, about as large as a football field, on the bank of a meandering creek. Still surviving were the wooden foundations of a long, rectangular building, which was subdivided into a dozen rooms, each containing food remains and clay-lined fire pits. It seems to have been a communal residence divided into personal dwellings. About 100 feet from these living quarters stood a wishbone-shaped structure accompanied by tools and butchered animal parts — likely a work area.

The archaeologists also recovered spun grass rope, wooden lances, animal hides and human feces from the site. Perishable items like these are rarely preserved at archaeological sites. But because Monte Verde is below peat deposits, organic materials were protected from decomposition. Food scraps also survived, revealing the people gathered at least 60 species of edible and medicinal plants, including a variety of seaweed species brought from the coast. And they hunted now-extinct creatures such as paleocamelids (an ancestor of llama and alpaca) and elephant-like gomphotheres.

Breaking the Clovis Barrier
Just as significant, though, is what the excavators did not find: Monte Verde lacked Clovis points — distinctive stone tools found at North American sites dating to roughly 13,000 years ago. Through much of the 20th century, many archaeologists supported “Clovis First” — the hypothesis that the people who made these artifacts were the first inhabitants of the Americas. Reports of older pre-Clovis sites were dismissed on the grounds that they were incorrectly excavated or dated.

But Monte Verde was remarkably well-preserved, meticulously excavated and analyzed with state-of-the-art methods. It convinced the archaeological community that non-Clovis peoples reached South America by at least 14,000 years ago. Clovis was not first.

Since then, numerous pre-Clovis sites have been reported between 13,300 and 15,000 years old. North America holds about 10 of them. But in South America, besides Monte Verde and its surrounding area, there are only two others: Huaca Prieta in Peru and Arroyo Seco in Argentina. With so few comparative sites, it’s difficult to say who and how widespread the Monte Verde people were.

Older Occupations
Dillehay and colleagues also reported potentially older artifacts from Monte Verde in a 1988 Nature paper. From a deeper layer dated to 30,000 years ago, they found three clay-lined burned areas and at least six stones that appear to have been shaped into tools. However, the finds were considered too meager to constitute a strong case for human presence.

Decades later, in 2013, Dillehay returned to the site to lead a team that dug 80 probes and test pits in the land around Monte Verde. The work, published in a 2015 PLOS One paper, identified 12 discrete spots with signs of a campfire (charcoal, ash, burned clay), stone tools and animal bones. Radiocarbon analysis dated the finds between 14,500 and 19,000 years ago.

The results suggest even earlier peopling of the Americas. Future work at Monte Verde may prove it.

Wednesday, January 20, 2021

America's Early Peoples (mostly on the Pacific Coast)

For decades, archaeologists associated finely fluted spear points—such as the two points at right—with the first people to live in the Americas. Image: Denver Museum of Nature & Science

A November 14, 2019, "Why it’s so challenging to determine ‘how and when’ humans first set foot in the Americas" by Megan Gannon published by the Genetic Literacy Project tells us that some arrived in North America by boat. The following information is gleaned from her article...

In 2014, a group of Canadian researchers uncovered human footprints pressed into a prehistoric layer of soil. The footprints, 29 in total, are the oldest found in North America. They suggest that 13,000 years ago, at least 3 people may have splashed out of a boat onto the damp shore.

North & South America seem to be the last major landmasses in the world to be populated by Homo sapiens. But the explanation of how & when this peopling happened has been heavily revised in the last 2 decades. New data, especially from the Pacific coast areas, including genetic findings, continue to complicate the story of how these continents came to be peopled.

The search intrigued archaeologist Edgar B. Howard when he learned in 1932, of mammalian fossils coming from a site called Blackwater Draw in New Mexico. A construction crew had exposed an extensive deposit of bison & mammoth bones, & there Howard found spear points & other human artifacts scattered among the remains of extinct mammoths, camels, & bison. At the time, researchers were only beginning to appreciate that humans were in the Americas during the last ice age, which ended around 10,000 years ago. In the years to follow, archaeologists would unearth sleek, fluted spear points, just like the ones found at Clovis, across North America. These artifacts came to be known as Clovis points & linked to people whom archaeologists considered the “first Americans.”

In the 1930s it was a  belief among many anthropologists that ancestral Native Americans descended from people living in Asia who crossed into the Americas over a now-submerged open tundra bridging Russia & Alaska, the Bering Land Bridge, also known as Beringia. From there, these people were speculated to have traversed a narrow passage between glaciers covering Alaska & Canada that only opened up about 13,500 years ago. The prevalence of Clovis-style spear points, which generally date between 13,250 & 12,800 years old, suggested that the first people in the Americas spread quickly after their arrival. Scientists broadly referred to this narrative—encompassing not just the cultural artifacts but also the time frame & land bridge—as the Clovis-first model.

Eventually cracks appeared in the Clovis-first model. In 1976 Chile, researchers excavating at Monte Verde uncovered undeniable traces of a human presence, preserved under peat. Researchers have confidently dated the most substantial cultural layer to about 14,500 years before the present day—at least 1,000 years older than the Clovis-first model would predict. We learned that people slept there under a long, tent-like structure made of wood & animal hides & sat around communal hearths eating potatoes & seaweed brought from trips to the coast.  In 1997, Monte Verde was inspected by a delegation of archaeologists, many of whom had questioned its purported age. They left in agreement that the site was old, indeed. Since then, in North America, several sites have gained wide acceptance as authentically pre-Clovis, but most of these older sites have no distinct artifacts to connect them.

At Oregon’s Paisley Caves, archaeologists have dated fossilized human feces to 14,300 years ago. Beneath the Clovis layers along the shores of Buttermilk Creek in Texas, researchers have found thousands of stone tool fragments dating back 15,500 years. And on the Atlantic coast side of the nation, reportedly, The Meadowcroft Rockshelter in Pennsylvania, has a human history that may stretch back at least 16,000 years. 

Most archaeologists, even the most conservative, would now agree that there were widely scattered, small but culturally diverse groups of people living in the Americas at least one or two millennia before the emergence of Clovis spear points.

Genetics also shed light on how & when entire lineages of people moved across continents. Genetic markers from the DNA of a child buried in what is now Alaska around 11,500 years ago, for instance, recently revealed that she shared equal DNA with all Indigenous populations in the Americas. The authors concluded she was likely descended from a population that remained in Beringia, instead of spreading through the lower continents. The Beringian population seems to have diverged from Siberian populations around 36,000 years ago. About 25,000 years ago, the Beringians became isolated, & a new genetic population emerged, one that scientists have confirmed relates to contemporary Native American people, splitting into 2 main lineages around 17,000 years ago. However, only a handful of ice age human remains have been studied at all—and archaeological data are needed to both confirm that story & help fill in the ancient pathways that humans first took across the continents.

The genetic data suggest one population may have spent thousands of years in Beringia, before spreading south into the Americas sometime during the Last Glacial Maximum between 27,000 & 19,000 years ago. Because of the ice, some claim that migrating people of the period did not walk but used boats. According to this coastal migration theory, some 16,000 years ago the ice had retreated from the coastlines of the Pacific Northwest, such that oceangoing people could take advantage of coastal resources like kelp forests to navigate all the way down the shores of California, eventually reaching sites like Monte Verde in Chile But no wooden boats from that era have been found along these shorelines. Some speculate that evidence of human habitation from at least 13,000 years ago on the Channel Islands in California indicates that people probably had the skills to build boats & reach these land masses.

Tuesday, January 19, 2021

An Extremely Fast Peopling of the Early Americas

Sebastian Munster Map of North & South America c 156

Two genetic studies show how the first Native Americans spread through their new continent with incredible speed.
The Atlantic  by ED YONG  November 8, 2018

Tens of thousands of years ago, two gigantic ice sheets smothered the northernmost parts of what has since been named North America. They towered more than two kilometers high and contained 1.5 times as much water as Antarctica does today. They were daunting, impassable barriers to the early humans who had started moving east from Asia, walking across a land bridge that once connected the regions now known as Russia and Alaska. But once the ice started to melt, these peoples—the ancestors of the Americas’ Indigenous groups—spread southward into new lands.

What happened next?

Genetic studies, based on ancient remains, had already suggested that once the first American Indians got south of the ice, 14,600 to 17,500 years ago, they split into two main branches. One stayed north, giving rise to the Algonquian-speaking peoples of Canada. The other headed south, giving rise to the widespread Clovis culture, and to Central and South Americans. That’s a very rough outline, but a new study from J. Víctor Moreno-Mayar and his colleagues fleshes it out. They showed that whatever happened south of the ice, it happened fast.

They sequenced the genomes of 15 ancient humans, who came from sites ranging all the way from Alaska to Patagonia. One person from Spirit Cave in Nevada and five from Lagoa Santa in Brazil were especially instructive. They were all just over 10,000 years old, and though they lived 6,300 miles apart, they were strikingly similar in their DNA. Genetically, they were also closely matched to Anzick-1—a famous Clovis infant from Montana, who was about 2,000 years older.

All this suggests that, about 14,000 years ago, the southern lineage of early American Indians spread through the continent with blinding speed. To picture their movements, don’t think of a slowly growing tree, incrementally sending out new branches and twigs. Instead, imagine a starburst, with many rays zooming out simultaneously and rapidly.

In a matter of centuries, these people had gone down both sides of the Rockies, across the Great Basin, and into Mexico’s highlands. Within a couple more millennia, they had zipped down the Andes, through the Amazon, and as far south as the continent allowed. “Once they were south of the ice, they found a territory that was open, vast, and full of resources,” says Moreno-Mayar, who is based at the University of Copenhagen. “They were adept hunter-gatherers, so they expanded very quickly.”

This pattern confirms the suspicions of archaeologists, whose finds had long suggested that humans suddenly appeared throughout the Americas, from about 13,000 years ago onward. “You can now see that in the genetics,” Moreno-Mayar says.

Coincidentally, a second group of researchers, fronted by Cosimo Posth of the Max Planck Institute for the Science of Human History, independently found the same pattern. They studied the DNA of 49 ancient humans from Central and South America and found similar evidence for a rapid starburst expansion, and a southward migration that connects the Clovis culture of the north to early peoples in Belize, Brazil, and Chile.

These studies show that the histories of the Americas are more complicated than earlier genetic studies suggested, says Deborah Bolnick, an anthropologist from the University of Connecticut. But that’s more because those studies were overly simplistic to begin with rather than because the new results are surprising. “Many lines of evidence, including archaeological research, linguistic data, and Indigenous histories, have suggested that multiple groups of people—related, descended from shared ancestors, but still distinct—have lived, moved, and interacted in the Americas over the millennia,” she says. “Broadly, that is what these [new] studies show.”

They’re not just reinventing the wheel, though. For example, the tools of the Clovis people were so different from those found at Spirit Cave (which lies on the other side of the Rockies) that some researchers took them as evidence that the Americas were peopled by two genetically distinct founding groups. Moreno-Mayar and his colleagues have disproved that idea: They showed that the two groups were genetically similar, if culturally distinct.

Both teams also found evidence of later waves of migration that took place long after the Americas had been initially peopled—although the details differ between the two studies. Posth’s data point to a second wave of people who entered South America about 9,000 years ago, whose genes displaced those of the earlier Clovis-related people, and who had a direct connection to Indigenous groups today. By contrast, Moreno-Mayar’s data speak to a gentler process, in which relatively small groups slowly spread both north and south from Mexico from 8,000 years ago, adding their genes to the local populations without swamping them. Either way, they “challenge the idea that present-day native peoples all descend from a single, homogenous ancestral population,” says Maria Nieves-Colón, a geneticist based in Mexico’s langebio institute.

The two studies also differ on a particularly puzzling and controversial result. Back in 2015, the leaders of both Posth’s and Moreno-Mayar’s teams found that today’s Indigenous Amazonians share small hints of ancestry with people from Australia and Papua New Guinea—places on the other side of the Pacific. In their new study, Moreno-Mayar’s team found that same tantalizing smidgen of Australasian ancestry in the 10,400-year-old remains from Lagoa Santa in Brazil, but in none of the other remains they tested. “Every explanation that we can come up with for that is less plausible than the last,” says Moreno-Mayar.

If people with Australasian ancestry somehow entered the Americas before the early American Indians, how did they get into Brazil without leaving any trace in North America, either genetically or archaeologically? If they entered after the first American Indians did, how did they get from Alaska to Brazil seemingly without interacting with anyone else? If they sailed across the entire Pacific, after hypothetically inventing seafaring technology millennia before the Polynesians, how did they cross the Andes and traverse the Amazon?

It doesn’t help that Posth’s team didn’t find any Australasian DNA among their ancient remains, including ones from the same region of Brazil. It could be that people from that area were very diverse—or that the Australasian signal is a mistake. “The only way to get a better answer is to do more studies on other ancient samples,” adds Moreno-Mayar.

Monday, January 18, 2021

Study reveals 10,000 years of Genetic Continuity in Northwest North America

Researchers are analyzing DNA from ancient individuals found in southeast Alaska, coastal British Columbia, Washington state and Montana. A new genetic analysis of individuals dating to at least 10,300 years ago. Graphic by Julie McMahon, University of Illinois

A study of the DNA in ancient skeletal remains adds to the evidence that indigenous groups living today in southern Alaska and the western coast of British Columbia are descendants of the first humans to make their home in northwest North America more than 10,000 years ago.some of these human remains finds that many of today’s indigenous peoples living in the same regions are descendants of ancient 
“Our analysis suggests that this is the same population living in this part of the world over time, so we have genetic continuity from 10,000 years ago to the present,” said University of Illinois anthropology professor Ripan Malhi, who led the study with University of Chicago postdoctoral researcher John Lindo; Penn State University biology professor Michael DeGiorgio; Rosita Worl, the director of the Sealaska Heritage Institute in Juneau, Alaska; and University of Oklahoma anthropology professor Brian M. Kemp.

The findings, reported in the Proceedings of the National Academy of Sciences, also suggest that these early American peoples had a complex population history, the researchers report.

The new work comes on the heels of earlier studies of ancient Americans that focused on mitochondrial DNA, which occurs outside the nucleus of cells and is passed only from mothers to their offspring.

“Mitochondrial DNA just traces the maternal line – your mother’s mother’s lineage – so, you’re missing information about all of these other ancestors,” said Lindo, the first author on the paper. “We wanted to analyze the nuclear genome so we could get a better assessment of the population history of this region.”

The team looked at genomic data from Shuká Káa (Tlingit for “Man Before Us”), an ancient individual whose remains – found in a cave in southeastern Alaska – date to about 10,300 years ago. They also analyzed the genomes of three more individuals from the nearby coast of British Columbia whose remains date to between 6,075 and 1,750 years ago.

“Interestingly, the mitochondrial type that Shuká Káa belonged to was also observed from another ancient skeleton dated to about 6,000 years ago,” Kemp said. “It seems to disappear after that. The nuclear DNA suggests that this is probably not about population replacement, but rather chance occurrence through time. If a female has no children or only sons, the mitochondrial DNA is not passed to the next generation. As a male, Shuká Káa could not have passed on his own mitochondrial DNA; he must have had some maternal relatives that did so.”
The researchers turned their attention to nuclear DNA, which offers a more comprehensive record of a person’s ancestry.

“DNA from the mitochondria and Y chromosome provide unique yet sometimes conflicting stories, but the nuclear genome provides a more comprehensive view of past events,” DeGiorgio said.

“The data suggest that there were multiple genetic lineages in the Americas from at least 10,300 years ago,” Malhi said.

The descendants of some of those lineages are still living in the same region today, and a few are co-authors on the new study. Their participation is the result of a long-term collaboration between the scientists and several native groups who are embracing genomic studies as a way to learn from their ancestors, said Worl, who is Tlingit, Ch’áak’ (Eagle) moiety of the Shangukeidí­ (Thunderbird) Clan from the Kawdliyaayi Hít (House Lowered From the Sun) in Klukwan, Alaska.

“We supported DNA testing of Shuká Káa because we believed science ultimately would agree with what our oral traditions have always said – that we have lived in southeast Alaska since time immemorial. The initial analysis showed the young man was native, and now further studies are showing that our ancestral lineage stems from the first initial peopling of the region,” said Worl, who also is an anthropologist. “Science is corroborating our oral histories.”

Sunday, January 17, 2021

Ancient Peoples Migrate between Siberia & Western North America

Beringa  Map of what was once the Beringia connection between present-day Siberia and Alaska. (National Park Service)

Ancient DNA Reveals Complex Story of Human Migration Between Siberia & North America. Two studies greatly increase the amount of information about the peoples who first populated North America—from the Arctic to the Southwest U.S.  Arctic hunter-gatherers, Paleo-Eskimos, made a significant genetic contribution to populations living in North America today. 

By Brian Handwerk June 5, 2019

There is plenty of evidence to suggest that humans migrated to the North American continent via Beringia, a land mass that once bridged the sea between what is now Siberia and Alaska. But exactly who crossed, or recrossed, and who survived as ancestors of today’s Native Americans has been a matter of long debate.

Two new DNA studies sourced from rare fossils on both sides of the Bering Strait help write new chapters in the stories of these prehistoric peoples.

The first study delves into the genetics of North American peoples, the Paleo-Eskimos (some of the earliest people to populate the Arctic) and their descendants. “[The research] focuses on the populations living in the past and today in northern North America, and it shows interesting links between Na-Dene speakers with both the first peoples to migrate into the Americas and Paleo-Eskimo peoples,” Anne Stone, an anthropological geneticist at Arizona State University who assessed both studies for Nature, says via email.

Beringia had formed by about 34,000 years ago, and the first mammoth-hunting humans crossed it more than 15,000 years ago and perhaps far earlier. A later, major migration some 5,000 years ago by people known as Paleo-Eskimos spread out across many regions of the American Arctic and Greenland. But whether they are direct ancestors of today’s Eskimo-Aleut and Na-Dene speaking peoples, or if they were displaced by a later migration of the Neo-Eskimos, or Thule people, about 800 years ago, has remained something of a mystery.

An international team studied the remains of 48 ancient humans from the region, as well as 93 living Alaskan Iñupiat and West Siberian peoples. Their work not only added to the relatively small number of ancient genomes from the region, but it also attempted to fit all the data together into a single population model.

The findings reveal that both ancient and modern peoples in the American Arctic and Siberia inherited many of their genes from Paleo-Eskimos. Descendants of this ancient population include the Yup’ik, Inuit, Aleuts and Na-Dene language speakers from Alaska and Northern Canada all the way to the Southwest United States. The findings stand in contrast to other genetic studies that had suggested the Paleo-Eskimos were an isolated people who vanished after some 4,000 years.

"For the last seven years, there has been a debate about whether Paleo-Eskimos contributed genetically to people living in North America today; our study resolves this debate and furthermore supports the theory that Paleo-Eskimos spread Na-Dene languages," co-author David Reich of Harvard Medical School and the Howard Hughes Medical Institute says in a press release.

The second study focused on Asian lineages, Stone notes. “The study is exciting because it gives us insight into the population dynamics, over 30-plus thousand years, that have occurred in northeastern Siberia. And these insights, of course, also provide information about the people who migrated to the Americas.”

Researchers retrieved genetic samples for 34 individuals’ remains in Siberia, dating from 600 to 31,600 years old. The latter are the oldest human remains known in the region, and they revealed a previously unknown group of Siberians. The DNA of one Siberian individual, about 10,000 years old, shows more genetic resemblance to Native Americans than any other remains found outside of the Americas.

Fifteen years ago scientists unearthed a 31,000-year-old site along Russia’s Yana River, well north of the Arctic Circle, with ancient animal bones, ivory and stone tools. But two tiny, children’s milk teeth are the only human remains recovered from the Ice Age site—and they yielded the only human genome yet known from people who lived in northeastern Siberia during the period before the Last Glacial Maximum. They represent a previously unrecognized population that the study’s international team of authors have dubbed “Ancient North Siberians.”

The authors suggest that during the Last Glacial Maximum (26,500 to 19,000 years ago) some of these 500 or so Siberians sought more habitable climes in southern Beringia. Stone says the migration illustrates the ways that shifting climate impacted ancient population dynamics. “I do think that the refugia during the Last Glacial Maximum were important,” she says. “As populations moved to refugia, likely following the animals they hunted and to take advantage of the plants they gathered as those distributions shifted south, this resulted in population interactions and changes. These populations then expanded out of the refugia as the climate warmed and these climate dynamics likely affected population around the world.”

In this case, the Ancient North Siberians arrived in Beringia and likely mixed with migrating peoples from East Asia. Their population eventually gave rise to both the First Peoples of North America and other lineages that dispersed through Siberia.

David Meltzer, an anthropologist at Southern Methodist University and coauthor of the new study, says when the Yana River site was discovered, the artifacts were said to look like the distinctive stone tools (specifically projectile “points”) of the Clovis culture—an early Native American population that lived in present-day New Mexico about 13,000 years ago. But the observation was greeted with skepticism because Yana was separated from America’s Clovis sites by 18,000 years, many hundreds of miles, and even the glaciers of the last Ice Age.

It seemed more likely that different populations simply made similar stone points in different places and times. “The odd thing is, now as it turns out, they were related,” Meltzer says. “It’s kind of cool. It doesn’t change the fact that there’s no direct historical descent in terms of the artifacts, but it does tell us that there was this population floating around in far northern Russia 31,000 years ago whose descendants contributed a bit of DNA to Native Americans.”

The finding isn’t particularly surprising given that at least some Native American ancestors have long been thought to hail from the Siberian region. But details that seemed unknowable are now coming to light after thousands of years. For example, the Ancient North Siberian peoples also appear to be ancestral to the Mal’ta individual (dated to 24,000 years ago) from the Lake Baikal region of southern Russia, a population that showed a slice of European roots—and from whom Native Americans, in turn, derived some 40 percent of their ancestry.

“It’s making its way to Native Americans,” Meltzer says of the ancient Yana genome, “but it’s doing so through various other populations that come and go on the Siberian landscape over the course of the Ice Age. Every genome that we get right now is telling us a lot of things that we didn’t know because ancient genomes in America and in Siberia from the Ice Age are rare.”

A more modern genome from 10,000-year-old remains found near Siberia’s Kolyma River evidences a DNA mix of East Asian and Ancient North Siberian lineages similar to that seen in Native American populations—a much closer match than any others found outside of North America. This finding, and others from both studies, serve as reminders that the tale of human admixture and migration in the Arctic wasn’t a one-way street.

“There’s absolutely nothing about the Bering land bridge that says you can’t go both ways,” Meltzer says. “It was open, relatively flat, no glaciers—it wasn’t like you wander through and the door closes behind you and you’re trapped in America. So there’s no reason to doubt that the Bering land bridge was trafficking humans in both directions during the Pleistocene. The idea of going back to Asia is a big deal for us, but they had no clue. They didn’t think they were going between continents. They were just moving around a large land mass.”

Saturday, January 16, 2021

Evidence seems to Reveal a 17,000-Year-Old Coastal Route Into North America

Illustration titled New Evidence Reveals a 17,000-Year-Old Coastal Route Into North America  Image: Bob Wilder/U. at Buffalo

A Possible 17,000-Year-Old Coastal Migration Route to North America  George Dvorsky  5/30/18

The first people to cross into North America from Eurasia did so by traveling through the Bering Strait, or so the theory goes. A new theory has emerged proposing a coastal route into the continent, but evidence has been lacking. A recent analysis of boulders, bedrock, and fossils in Alaska is now providing a clearer picture, pointing to the emergence of a coastal route some 17,000 years ago.

New research published today in Science Advances is offering some of the first geological evidence of an Alaskan coastal migration route that would have made it possible for humans to cross over from Eurasia into North America when the Ice Age was still going strong. Importantly, the paper also includes evidence of aquatic and terrestrial life in the region during the same time period, which means venturing humans would have had access to food. The University at Buffalo researchers aren’t saying humans definitely traveled along this coastal route—they’re just saying the conditions were set for human migration into North America starting around 17,000 years ago.

At the height of the last Ice Age, North America was separated from Eurasia by the massive Cordilleran Ice Sheet, preventing the flow of humans into the continent. Eventually, humans were able to make the trek, but scientists aren’t entirely sure which route they took, or the timing of the transcontinental leap.

During the 20th century, it was conventionally assumed that North America’s first peoples travelled through a narrow, ice-free corridor, but recent evidence has thrown a rather large wrench into this long-standing hypothesis. The retreating ice sheets didn’t yield an interior pathway until about 14,000 years ago, and the strip of land that suddenly became accessible wasn’t suitable for animals and humans until about 13,000 to 12,600 years ago. This presents a huge chronological problem, because archaeological evidence places humans in Chile around 15,000 years ago, and in Florida some 14,500 years ago.

Hence the Coastal Migration Theory, also known as the Kelp Highway Hypothesis. Instead of traveling through an interior route, it’s counterargued, human migrants hugged the Siberian, Beringian, and Alaskan coastlines, eventually making their way into North and South America. There’s practically no archaeological evidence to support this theory, but the recent discovery of 29 footprints on the shoreline of Calvert Island in British Columbia, dated at 13,000 years old, teases at the possibility. Complicating matters, scientists aren’t even sure if the glaciers completely blocked the coastal route, or when the ice sheets retreated to make the route available for human migration.

To answer these questions, Lesnek’s team visited four islands within Alaska’s Alexander Archipelago, which is located about 200 miles (360 km) south of Juneau. Looking at the physical evidence, it was clear to the team that ice once dominated the area. “The landscape is glacial,” said Jason Briner, lead author of the study and a geologist at the University at Buffalo, in a statement. “The rock surfaces are smooth and scratched from when the ice moved over it, and there are erratic boulders everywhere. When you are a geologist, it hits you in the face. You know it immediately: The glacier was here.”

Using a technique known as surface exposure dating, the researchers were able to figure out when the ice began to retreat. Chemical signatures within the rocks and bedrock tell scientists when ice no longer provided a barrier to the elements. “This definitively tells us that the glaciers in southeastern Alaska retreated from the coast 17,000 years ago,” Lesnek told Gizmodo. “We also took advantage of a rich archive of fossils found in a cave on Prince of Wales Island. By radiocarbon dating the bones and identifying which animals they came from, we were able to determine that ringed seal and arctic fox were living in southeastern Alaska when the coastal route opened.”

Lesnek and her colleagues were surprised that glaciers blocked the coastal route. Her team went into this project thinking that these areas had been completely ice-free during the last Ice Age. “But our results tell a different story,” she said. “We now know that the glaciers may have blocked the coastal route for a few thousand years. However, these glaciers retreated around 17,000 years ago, which opened the door for human migration along the coast,” said Lesnek. “The timing of glacier retreat lines up very well with the genetic and archaeological evidence for the peopling of the Americas.” Importantly, the new study only covers a very small portion of the coastal route, and other parts still remain undated. Lesnek says her team will continue to hunt for areas that may have escaped glaciation, and map the areas in which life was able to emerge in the immediate aftermath.

Ben Potter, a professor of anthropology at the University of Alaska Fairbanks who wasn’t involved in the new study, likes the new paper, saying the conclusion is plausible and that the researchers were wise to limit themselves to the notion that an early migration route along this part of the coast was possible, rather than saying it was likely or certain. “In archaeological science, we need deliberate, methodical analyses of all aspects of paleoecology, geology, etc., to understand human adaptation and expansion, including migration,” Potter told Gizmodo. “So this is a welcome study in understanding the complex deglaciation process in this part of the northwest coast.” Potter said scientists should continue these types analyses along the coast to learn more about the timing of glacial retreat, and to track changes in the environment and ecology during this critical time period. But he says the ultimate answer to the timing and nature of North American colonization will likely remain elusive for some time to come.

“The migration of one or more Native American populations into the Americas was likely a complex process, including between one and three major groups: the Ancient Beringians, North Native Americans, and South Native Americans,” said Potter. “The timing remains unknown, but likely post-dates 16,000 years ago, given the genetic evidence for expansion after this time.” He says the routes taken may have included the interior ice-free corridor, the coastal route—or, more likely, both. “Recent research has indicated ice free, proglacial lake free [a lake in front of a melting glacier], and vegetated conditions in the ice-free corridor by 15,000 years ago, and this new paper indicates livable conditions along the coast at 17,000 years ago,” he said. “Studies like this are absolutely necessary to properly situate hypotheses about the peopling of the Americas.”

Friday, January 15, 2021

Early peoples in Texas - 15,000 years ago

A 15,000-year-old stemmed point. (Center for the Study of the First Americans, Texas A&M University) (unknown/Center for the Study of the First Americans, Texas A&M University)

Continent’s oldest spear points provide new clues about the first Americans
Washington Post By Sarah Kaplan Oct. 24, 2018

For as long as Buttermilk Creek has wound its way through Texas Hill Country, its spring-fed waters have carved through the region’s dark, dense clays, cutting away layers of earth to expose the rock — & the history — below.

Here, archaeologists have uncovered evidence of a human settlement stretching back as far as 15,500 years: hammer stones & broken knives, fragments of fractured tools. And now, scientists say, the Buttermilk Creek complex has offered up the oldest known spearheads in North America.

The new “projectile points,” reported this week in the journal Science Advances, come in two unusual shapes — a fact that geologist Mike Waters, who oversaw the excavation, found both “bizarre” & “really exciting.” The find adds to the evidence that the first people arrived in the Americas earlier than researchers thought, even as it raises new questions about who those people were & how they made their epic migration into the continent.

“This is a really fascinating paper,” said Jennifer Raff, an anthropological geneticist at the University of Kansas who was not involved in the new study. “It’s filling in some of the gaps in the archaeological record regarding the Clovis complex & the histories of the very first peoples in the Americas.

If the projectile point was the cellphone of the Pleistocene — an omnipresent technology that shaped cultures & defined daily life — the Clovis tools were the iPhone X. These points, named for the city in New Mexico where they were first found, featured a fluted bottom & rounded sides tapering to a sharp point.

The distinctive spearheads are scattered throughout the rock record between 10,000 & 13,500 years ago, from the East Coast to the Rocky Mountains & as far south as Venezuela. The tools are so ubiquitous that for nearly a century, archaeologists thought that the Clovis tradition represented the first people to arrive in the Americas.

But research in recent decades has revealed archaeological sites much older than Clovis, & genetic analyses of modern Native Americans suggest their ancestors crossed a land bridge from Asia to Alaska about 20,000 years ago, then migrated down the Pacific coast between 20,000 & 15,000 years before present.

So who exactly were these early Americans?

The new points uncovered at Buttermilk Creek may offer a clue, said Waters, who directs the Center for the Study of the First Americans at Texas A&M University. Because tools are so essential to the tasks of survival — hunting, cooking, building, killing — they can say a great deal about the people who wielded them.

In more than 10 years of excavations at his site, Waters & his colleagues have found Clovis points in a rock layer dating to about 13,000 years ago. Below that, in older rocks, they uncovered scores of stone point fragments, but no whole spearheads. It was difficult to know if they were looking at older Clovis artifacts, or something entirely different.

Then, in 2015, the archaeologists uncovered two perfectly preserved artifacts: One triangular point, which resembles a predator’s sharp tooth, & one lobe-shaped projectile with a tapered, or “stemmed,” bottom. With these whole points as models, Waters’s team was able to make sense of the 10 additional fragments they collected. They seemed subtly but significantly different from Clovis & other toolmaking traditions — neither a clear ancestor to the later technology, nor an obvious competitor.

“I just thought, ‘Holy cow,’” Waters recalled. “Whenever you see something for the first time that you didn’t expect, it’s always very exciting & exhilarating.”

Radiocarbon dating of the soils where the points were found suggested they were made between 13,500 & 15,500 years ago — offering a significant piece of archaeological evidence for a migration into the Americas that predates Clovis.

But the points also raise new questions, Waters said: Were the Clovis people descendants of these early inhabitants who came up with a new toolmaking technique? Or did they migrate separately into the continent before scattering their tools across the Americas? “We’re just beginning to answer that,” Waters said.

Skye Gilham, a forensic anthropologist who is a member of the Blackfeet tribe in northern Montana, said that recent archaeological & genetic research has been helpful in establishing a scientific link between the first Americans & their descendants living today. Findings like Waters', which provide evidence for her people’s long history in the Americas, have helped ensure the return of native remains to their communities. “We have said that we have always been here, our homeland,” Gilham said. Archaeology & genetics, she said, “reaffirm" that.

Thursday, January 14, 2021

Claim that Evidence shows 1st Americans came from the Pacific Coast

New Evidence Bolsters Theory That 1st Americans Arrived by the Pacific Coast  by George Dvorsky  8/29/19

Archaeological evidence excavated in western Idaho suggests humans were in the region well over 15,000 years ago—prior to the opening of the massive ice sheets that blocked entrance into North America via the Bering land bridge. It’s further evidence that the continent’s first people arrived by traveling along the Pacific coast.

Prior to the Late Upper Paleolithic, humans had established a presence on every habitable continent on the planet—except North and South America. A gigantic and impenetrable obstruction known as the Cordilleran Ice Sheet blocked entry from Siberia into Alaska, preventing human migration into the New World.

But as the last great Ice Age ended, so too did this colossal barrier. Around 14,800 years ago, the Cordilleran Ice Sheet separated from its neighboring Laurentide Ice Sheet, creating an ice-free corridor that extended from Beringia through to what is now the Dakotas. This dramatic change in the environment has led archaeologists to surmise that the earliest migrants to North America arrived by traversing this corridor, in what’s referred to, appropriately enough, as the Ice-Free Corridor Hypothesis.

Trouble is, emerging archaeological and genetic evidence is increasingly pointing to an arrival date in North America prior to 14,800 years ago, leading to the Coastal Migration Hypothesis. Instead of traveling through the interior, this theory proposes a route in which the first settlers of North America traveled south along the Pacific coast, eventually surpassing the southernmost extent of the ice sheets.

New research published today in Science offers some of the earliest archaeological evidence of humans in North America, further bolstering the Coastal Migration Hypothesis. Working at the Cooper’s Ferry site in western Idaho, a team led by Loren Davis, a professor of anthropology at Oregon State University, uncovered stone tools, animal bones, traces of fire pits, and other signs of human occupation dated to between 16,560 and 15,280 years ago—several centuries prior to the appearance of the ice-free corridor.

“This is so cool,” Christiana Scheib, an archaeologist and paleogeneticist from the University of Cambridge, told Gizmodo. “This is a great example of the kind of archaeology we need happening in order to better understand the First Peoples in the Americas,” said Scheib, who wasn’t involved with the new study.

Archaeologist Alia Lesnek from the Department of Geology at the University at Buffalo, also not affiliated with the new study, said the new paper “presents an exciting new dataset that provides convincing evidence of human presence in modern-day Idaho as early as 15,300 years ago,” and that these results “add to a growing body of research suggesting that the First Americans arrived in North America by traveling along the Pacific coast.”

Last year, Lesnek and her colleagues uncovered potential geological evidence of an Alaskan coastal migration route that could have allowed humans to cross over from Eurasia into North America during the Ice Age.

But not everyone is convinced by the new evidence. One archaeologist we spoke to said more work will be required to validate the results presented in the new paper. The study describes findings from one of two excavation sites at Cooper’s Ferry, which has been investigated by archaeologists since the late 1990s.

“The Cooper’s Ferry site is located along the Salmon River, which is a tributary of the larger Columbia River basin,” said Davis in a press release. “Early peoples moving south along the Pacific coast would have encountered the Columbia River as the first place below the glaciers where they could easily walk and paddle in to North America. Essentially, the Columbia River corridor was the first off-ramp of a Pacific coast migration route.” To which he added: “The timing and position of the Cooper’s Ferry site is consistent with and most easily explained as the result of an early Pacific coastal migration.”

Buried within the deepest layers of the site, Loren’s team found hundreds of artifacts, including stone tools, fire-cracked rocks used in hearths, bone fragments from possibly prey, and other evidence of human occupation, such as areas used for processing food. Tooth fragments from an extinct horse were also uncovered, though its connection to the settlement is not entirely clear.

Radiocarbon dating of animal bone fragments and burnt charcoal suggests the site was repeatedly occupied between 16,560 and 15,280 years ago. “Prior to getting these radiocarbon ages, the oldest things we’d found dated mostly in the 13,000-year range, and the earliest evidence of people in the Americas had been dated to just before 14,000 years old in a handful of other sites,” explained Davis. “When I first saw that the lower archaeological layer contained radiocarbon ages older than 14,000 years, I was stunned but skeptical and needed to see those numbers repeated over and over just to be sure they’re right. So we ran more radiocarbon dates, and the lower layer consistently dated between 14,000-16,000 years old.”

The new paper subsequently challenges the longstanding “Clovis First” theory of North American colonization, which proposes that the first migrants to the continent arrived via the interior ice-free route, eventually reaching the Dakotas. What’s more, the authors presented evidence showing that the tools used by the Cooper’s Ferry migrants were of a distinctly non-Clovis-like nature. Specifically, these people employed unfluted and stemmed projectile points, and not the fluted, broad-based points indicative of Clovis culture. Loren and his colleagues also argued that the tools used by the Cooper’s Ferry people bear a striking resemblance to those found in contemporaneous cultures living in northeastern Asia, including Japan. This would seem to suggest that these early migrants retained knowledge of this technology as they settled into North America.

“My perspective is that Cooper’s Ferry is intriguing, but not paradigm-shifting.” Ben Potter, an archaeologist from the University of Alaska Fairbanks, had some issues with the new paper. “My perspective is that Cooper’s Ferry is intriguing, but not paradigm-shifting,” Potter told Gizmodo. “Much more work needs to be done to establish the nature and age of the occupations.”

Potter expressed concerns about the layer itself, which he described as a hodge-podge of “multiple potentially overlapping components over four thousand years.” He also didn’t love the fact that the majority of dates established within the investigated layer were less than 13,800 years old (10 out of the 18 ages reported). There is “no good reason to hypothesize occupation” at more than 16,000 years ago “because of a few widely scattered charcoal fragments not directly linked to cultural feature, and one from a feature with much later ages,” he said. The date presented in the study most closely linked with stemmed points at other sites, around 11,600 years old, or the oldest hearth with a few flakes between 15,000-14,000 years old, he said, do not “preclude passage through the Ice Free Corridor and/or the Pacific coast,” and by “no means do these data refute the [ice-free corridor] hypothesis. Both interior and coastal routes remain viable,” he said.

On a similar note, Lesnek thought it important to point out that the oldest age established for the site, at over 16,500 years old, was not established directly from material that was actually dated. “Rather, that age comes from a statistical modeling program that uses dates from the entire sediment layer to estimate when the event—in this case occupation by humans—began,” Lesnek told Gizmodo. “However, the statistical modeling program the authors employ is robust and widely used in archeology and earth sciences. In addition, even if the authors used the oldest radiocarbon date to determine the age of the site, that would put humans in North America by 15,300 years ago, which precludes that the initial migration to the Americas took place through the ice-free corridor.”

Potter described the comparisons of the stemmed points with Japanese tools as being “superficial and unconvincing,” without “any technological analysis to support the hypothesized connections.” Similarly, Scheib said this connection was “interesting,” but it “doesn’t mean that these people came directly from there,” she told Gizmodo.

Scheib, who studies the DNA of America’s first people, said an early genetic split occurred among North America’s first settlers, and it may have happened around the time of the Cooper’s Ferry settlement. “One group is associated with Clovis tools and related to modern Central and South Americans and the other is related to modern North Americans,” Scheib told Gizmodo. “It would be very interesting to know whether the early people at Cooper’s Ferry are genetically more like one or the other. Or if this is the time when these two groups are actually becoming distinct entities.” Genetic evidence from Cooper’s Ferry—which has yet to be uncovered—could tell us more about how and where these two populations diverged, she said. Finding DNA could be tough but not impossible.

“The cultural material at Cooper’s Ferry was only accessible due to the construction of a road in the 1930s, which removed about 15 feet of sediment,” Lesnek told Gizmodo. “It may very well be that other ancient archeological sites are buried across North America, but we haven’t found them yet.”

Wednesday, January 13, 2021

Did an Agricultural Society become dominant 5,000-10,000 Years Ago

From the Associated Press By RANDOLPH E. SCHMID, AP Science Writer Randolph E. Schmid, Ap Science Writer – Monday, March 7, 2011 

WASHINGTON – Thousands of years ago, our ancestors gave up foraging for food and took up farming, one of the most important and debated decisions in history.

Was farming more efficient than foraging? Did the easily hunted animals die out? Did the environment change? A new study by Samuel Bowles of the Santa Fe Institute in New Mexico argues that early farming was not more productive than foraging, but people took it up for social and demographic reasons.

In Monday's edition of Proceedings of the National Academy of Sciences, Bowles analyzed what it would take to farm under primitive conditions. He concluded farming produced only about three-fifths of the food gained from foraging.

But, Bowles notes, farming became the most common way of living between 10,000 and 5,000 years ago because of its contribution to population growth and military power.

Without the need for constant movement, child-rearing would have been easier and safer, leading to a population increase, Bowles said. And since stored grain might be looted, farmer communities could have banded together for defense and would have eventually pushed out neighboring foragers, he suggests.

Brian Fagan, a professor emeritus of archaeology at the University of California, Santa Barbara, called Bowles' ideas "provocative and fascinating." It had been suspected that the earliest farming was not necessarily more productive, said Fagan, who was not part of the research. "What he does is to draw attention to the social and demographic factors that contributed so importantly to the spread of farming," Fagan said. "This is a useful contribution to a debate about agricultural origins that has been under way for generations."

Samuel Bowles Abstract:

Cultivation of cereals by the first farmers was not more productive than foraging
Did foragers become farmers because cultivation of crops was simply a better way to make a living? If so, what is arguably the greatest ever revolution in human livelihoods is readily explained. To answer the question, I estimate the caloric returns per hour of labor devoted to foraging wild species and cultivating the cereals exploited by the first farmers, using data on foragers and land-abundant hand-tool farmers in the ethnographic and historical record, as well as archaeological evidence. A convincing answer must account not only for the work of foraging and cultivation but also for storage, processing, and other indirect labor, and for the costs associated with the delayed nature of agricultural production and the greater exposure to risk of those whose livelihoods depended on a few cultivars rather than a larger number of wild species. Notwithstanding the considerable uncertainty to which these estimates inevitably are subject, the evidence is inconsistent with the hypothesis that the productivity of the first farmers exceeded that of early Holocene foragers. Social and demographic aspects of farming, rather than its productivity, may have been essential to its emergence and spread. Prominent among these aspects may have been the contribution of farming to population growth and to military prowess, both promoting the spread of farming as a livelihood.

Santa Fe Institute, Santa Fe, NM, 87501; and University of Siena, Siena 53100, Italy
Edited by Henry T. Wright, University of Michigan, Ann Arbor, MI, & approved February 2, 2011 (received for review July 26, 2010)

Full article from The Proceedings of the National Academy of Sciences for the United States of America.

Tuesday, January 12, 2021

Some Controversy about claims that the Oldest Evidence of North American Settlement May Have Been Found

The Cooper's Ferry archeological site is in western Idaho.

Oldest Evidence of North American Settlement May Have Been Found in Idaho

The first settlers of North America might have been seafarers

Humans might have first settled North America around 16,000 years ago, setting off on boats from northeast Asia and traveling along the Pacific Coast, new findings suggest. That's the earliest evidence yet of settlement in this region.

The mystery of how the first settlers arrived in North America remains hotly debated. For years, the dominant theory has been that the first people to arrive in North America walked across the Bering Land Bridge, which connected Asia and North America, when sea levels dropped at the end of the last ice age. From there, the theory holds, they followed an ice-free corridor which opened around 14,800 years ago, down to North America.

But growing evidence suggests that the first settlers didn't trudge through a flat, grassy plain following large prey, but rather set off along the Pacific Coast in ancient boats.

This ancient migration was one of the last major movements of people across the planet, said lead author Loren Davis, a professor of anthropology at Oregon State University. So, "people have a sense of wonder" about this journey, Davis said.

To re-create the picture of this vast, ancient migration, Davis and his team analyzed ancient remains found at the Cooper's Ferry archaeological site, which sits at the junction of the Rock Creek and the lower Salmon River in western Idaho.

The Cooper's Ferry site was first excavated back in the 1960s. Prior to that, it was once an ancient village called Nipéhe, according to oral histories recounted to Davis by the Niimíipuu tribe. Between 2009 and 2018, Davis and his team opened up and excavated two large holes in the ground — one of which is the focus of this study. In that pit, spanning just 23 feet by 43 feet (7 meters by 13 meters), they discovered a trove of early remains and artifacts.

The team uncovered 189 artifacts, including 27 stone tools and 161 pieces of debitage, or flakes of rock created in the process of making stone tools. The tools included stemmed point fragments, which have previously been found all around the western U.S.

They also found bone fragments from an extinct horse, Davis said. Around the animal bone fragments the team discovered numerous stone tools. A little ways away, they found something resembling a hearth or fire pit. "We think that represents someone butchering a horse," and then possibly cooking and eating it, Davis told Live Science.

This might be "the earliest radiocarbon-dated evidence of people interacting with extinct animals in North America," Davis said. Through radiocarbon dating, a method that analyzes radioactive carbon in biological samples to figure out their ages, they found that biological samples in the hearth were similar in age to the bones.

The radiocarbon dating of these charcoal and bone samples revealed that people occupied the area for a long period of time, but the oldest biological samples were between 16,560 and 15,280 years old. Since they were found in the same layers as human artifacts, such as tools, they are likely of similar age, Davis said.

For a long time, it was thought that the first settlers of the Americas were the "Clovis" people who arrived around 13,000 years ago. But later excavations at various sites in North and South America revealed evidence of settlements that predated the Clovis culture, such as Monte Verde in Chile, which has some artifacts of human settlement that date to between 14,000 and 19,000 years ago.

These new results suggest that humans already lived in Idaho around 16,000 years ago — over a thousand years earlier than the time during which an ice-free corridor opened up across the western U.S. "So you might say that we refuted the hypothesis of the ice-free corridor," Davis said. The findings lend "great support to the idea that people came down the Pacific Coast instead."

This study "provides further support for the Pacific coast as the route by which Native Americans arrived in mid-latitude North America," said John Hoffecker, a fellow at the Institute of Arctic and Alpine Research at the University of Colorado, Boulder, who was not a part of the study. But "the authors have exaggerated the results of the dating." The dating suggests that the "earliest occupation of Cooper's Ferry is likely to be somewhat younger," closer to 15,000 years ago, Hoffecker told Live Science.

The authors suggest that some of the tools they found at Cooper's Ferry, such as the spear or dart points, are very similar to those found in northern Japan from a similar time. "So one hypothesis is simply that you're looking at the extension culturally of people that are bringing these ideas with them from northern Japan," Davis said.

But "both genetics and dental anthropology indicate unequivocally that Native Americans are not derived from northern Japan," Hoffecker said referring to the ancient people who lived in Japan.

The comparison of these Western stemmed points with Japanese counterparts is "superficial and unconvincing, based on five specimens selected for suggested morphological similarity," said Ben Potter, the department chair and a professor of archeology at the University of Alaska Fairbanks, who was also not a part of the study.

What's more, the findings don't refute the idea that the first people arrived via the ice-free corridor, he said. The feature with the "oldest consistent dates," does not preclude the passage through the ice-free corridor, he said.

In any case, "there appears to be an interesting and dynamic geoarchaeological story here," Potter told Live Science. "My perspective is that Cooper’s Ferry is intriguing, but not paradigm shifting."

Next, Davis and his team hope to further explore if there really is a connection between these ancient inhabitants and the people of ancient Japan and spend more time analyzing the artifacts that they spent a decade excavating.

Monday, January 11, 2021

Ancient DNA retells Story of Caribbean's First People, with a few Plot Twists...

Ancient DNA retells Story of Caribbean's First People

Florida Museum of Natural History 3 Dec 2020

GAINESVILLE, Fla. --- "The history of the Caribbean's original islanders comes into sharper focus in a new Nature study that combines decades of archaeological work with advancements in genetic technology.

"An international team led by Harvard Medical School's David Reich analyzed the genomes of 263 individuals in the largest study of ancient human DNA in the Americas to date. The genetics trace two major migratory waves in the Caribbean by two distinct groups, thousands of years apart, revealing an archipelago settled by highly mobile people, with distant relatives often living on different islands.

"Reich's lab also developed a new genetic technique for estimating past population size, showing the number of people living in the Caribbean when Europeans arrived was far smaller than previously thought - likely in the tens of thousands, rather than the million or more reported by Columbus and his successors.

"For archaeologist William Keegan, whose work in the Caribbean spans more than 40 years, ancient DNA offers a powerful new tool to help resolve longstanding debates, confirm hypotheses and spotlight remaining mysteries. "This "moves our understanding of the Caribbean forward dramatically in one fell swoop," said Keegan, curator at the Florida Museum of Natural History and co-senior author of the study. "The methods David's team developed helped address questions I didn't even know we could address."

"Archaeologists often rely on the remnants of domestic life - pottery, tools, bone and shell discards - to piece together the past. Now, technological breakthroughs in the study of ancient DNA are shedding new light on the movement of animals and humans, particularly in the Caribbean where each island can be a unique microcosm of life.

"While the heat and humidity of the tropics can quickly break down organic matter, the human body contains a lockbox of genetic material: a small, unusually dense part of the bone protecting the inner ear. Primarily using this structure, researchers extracted and analyzed DNA from 174 people who lived in the Caribbean and Venezuela between 400 and 3,100 years ago, combining the data with 89 previously sequenced individuals.

"The team, which includes Caribbean-based scholars, received permission to carry out the genetic analysis from local governments and cultural institutions that acted as caretakers for the human remains. The authors also engaged representatives of Caribbean Indigenous communities in a discussion of their findings.

"The genetic evidence offers new insights into the peopling of the Caribbean. The islands' first inhabitants, a group of stone tool-users, boated to Cuba about 6,000 years ago, gradually expanding eastward to other islands during the region's Archaic Age. "Where they came from remains unclear - while they are more closely related to Central and South Americans than to North Americans, their genetics do not match any particular Indigenous group. However, similar artifacts found in Belize and Cuba may suggest a Central American origin," Keegan said.

"About 2,500-3,000 years ago, farmers and potters related to the Arawak-speakers of northeast South America established a second pathway into the Caribbean. Using the fingers of South America's Orinoco River Basin like highways, they travelled from the interior to coastal Venezuela and pushed north into the Caribbean Sea, settling Puerto Rico and eventually moving westward. Their arrival ushered in the region's Ceramic Age, marked by agriculture and the widespread production and use of pottery.

"Over time, nearly all genetic traces of Archaic Age people vanished, except for a holdout community in western Cuba that persisted as late as European arrival. Intermarriage between the two groups was rare, with only three individuals in the study showing mixed ancestry.

"Many present-day Cubans, Dominicans and Puerto Ricans are the descendants of Ceramic Age people, as well as European immigrants and enslaved Africans. But researchers noted only marginal evidence of Archaic Age ancestry in modern individuals.

"That's a big mystery," Keegan said. "For Cuba, it's especially curious that we don't see more Archaic ancestry."

"During the Ceramic Age, Caribbean pottery underwent at least five marked shifts in style over 2,000 years. Ornate red pottery decorated with white painted designs gave way to simple, buff-colored vessels, while other pots were punctuated with tiny dots and incisions or bore sculpted animal faces that likely doubled as handles. Some archaeologists pointed to these transitions as evidence for new migrations to the islands. But DNA tells a different story, suggesting all of the styles were developed by descendants of the people who arrived in the Caribbean 2,500-3,000 years ago, though they may have interacted with and took inspiration from outsiders.

"That was a question we might not have known to ask had we not had an archaeological expert on our team," said co-first author Kendra Sirak, a postdoctoral fellow in the Reich Lab. "We document this remarkable genetic continuity across changes in ceramic style. We talk about 'pots vs. people,' and to our knowledge, it's just pots."

"Highlighting the region's interconnectivity, a study of male X chromosomes uncovered 19 pairs of "genetic cousins" living on different islands - people who share the same amount of DNA as biological cousins but may be separated by generations. In the most striking example, one man was buried in the Bahamas while his relative was laid to rest about 600 miles away in the Dominican Republic.

"Showing relationships across different islands is really an amazing step forward," said Keegan, who added that shifting winds and currents can make passage between islands difficult. "I was really surprised to see these cousin pairings between islands."

"Uncovering such a high proportion of genetic cousins in a sample of fewer than 100 men is another indicator that the region's total population size was small," said Reich, professor of genetics in the Blavatnik Institute at HMS and professor of human evolutionary biology at Harvard. "When you sample two modern individuals, you don't often find that they're close relatives," he said. "Here, we're finding relatives all over the place."

"A technique developed by study co-author Harald Ringbauer, a postdoctoral fellow in the Reich Lab, used shared segments of DNA to estimate past population size, a method that could also be applied to future studies of ancient people. Ringbauer's technique showed about 10,000 to 50,000 people were living on two of the Caribbean's largest islands, Hispaniola and Puerto Rico, shortly before European arrival. "This falls far short of the million inhabitants Columbus described to his patrons, likely to impress them," Keegan said.

"Later, 16th-century historian Bartolomé de las Casas claimed the region had been home to 3 million people before being decimated by European enslavement and disease. While this, too, was an exaggeration, the number of people who died as a result of colonization remains an atrocity," Reich said. "This was a systematic program of cultural erasure. The fact that the number was not 1 million or millions of people, but rather tens of thousands, does not make that erasure any less significant," he said.

"For Keegan, collaborating with geneticists gave him the ability to prove some hypotheses he had argued for years - while upending others. "At this point, I don't care if I'm wrong or right," he said. "It's just exciting to have a firmer basis for reevaluating how we look at the past in the Caribbean. One of the most significant outcomes of this study is that it demonstrates just how important culture is in understanding human societies. Genes may be discrete, measurable units, but the human genome is culturally created."

Daniel Fernandes of the University of Vienna and the University of Coimbra in Portugal was also co-first author of the study. Other co-senior authors are Alfredo Coppa of the Sapienza University of Rome, Mark Lipson of HMS and Harvard and Ron Pinhasi of the University of Vienna.

An earlier article from June 2020

Illustration of one of the early settlers in the Caribbean. Image credit: Tom Björklund.

Humans Colonized Caribbean Islands in Three Waves: Study

Jun 5, 2020 Sci News

An international team of researchers has sequenced and analyzed the genomes of 93 ancient Caribbean islanders and found evidence of at least three separate population dispersals into the region: two early dispersals into the Western Caribbean, one of which seems connected to earlier population dispersals in North America; and a third, more recent wave from South America.

The Caribbean Islands were one of the last regions in the Americas to be settled by humans.

The earliest archeological evidence suggests that the Caribbean’s first residents arrived roughly 8,000 years ago, and by 5,000 years ago, were widely dispersed.

However, how, when and from where the region’s first colonists came to the islands of the Antilles isn’t well understood.

Much of the Caribbean’s settlement history has heavily relied on interpretations from archaeological findings, such as the stylistic comparison of artifact collections between Caribbean sites and those from the surrounding mainland.

While these approaches have illuminated broad-scale population movements, many of the more nuanced aspects of Caribbean population history remain unknown.

To fill these gaps, Kathrin Nägele from the Max Planck Institute for the Science of Human History and colleagues analyzed genome-wide data from 93 ancient Caribbean islanders who lived between 400 and 3,200 years ago using bone fragments excavated from 16 different archaeological sites across the Caribbean.

The analysis provided new genetic evidence of at least three separate colonization events, including two early dispersals into the Western Caribbean – one of which was previously unknown and may have been connected to radiation events in North America that predate the diversification of Central and South American populations.

Afterward, a later expansion of groups from South America arrived and brought new technologies, including pottery, supporting previous archaeological interpretations.

“The new data give us a fascinating glimpse of the early migration history of the Caribbean,” said senior co-author Dr. Hannes Schroeder, a researcher in the Globe Institute at the University of Copenhagen. “We find evidence that the islands were settled and resettled several times from different parts of the American mainland.”

“Big bodies of water are traditionally considered barriers for humans and ancient fisher-hunter-gatherer communities are usually not perceived as great seafarers,” Nägele said. “Our results continue to challenge that view, as they suggest that there was repeated interaction between the islands and the mainland.”

“The new data support our previous observations that the early settlers of the Caribbean were biologically and culturally diverse, adding resolution to this ancient period of our history,” said co-author Dr. Yadira Chinique de Armas, a researcher at the University of Winnipeg.

The team’s results also revealed distinct genetic differences between the ancestors of the region’s earliest settlers and the newcomers from South America.

Despite coexisting for centuries, the scientists found almost no evidence of admixture, raising intriguing new questions about their interactions.

“Although different groups were present in the Caribbean at the same time, we found surprisingly little evidence of admixture between them,” said co-author Dr. Cosimo Posth, a researcher at the Max Planck Institute for the Science of Human History.

“The results of this study provide yet another layer of data that highlights the diverse and complex nature of pre-Columbian Caribbean societies and their connections to the American mainland prior to the colonial invasion,” said co-author Professor Corinne Hofman, a scientist at Leiden University.

The findings were published in the journal Science. Kathrin Nägele et al. Genomic insights into the early peopling of the Caribbean. Science, published online June 4, 2020

Sunday, January 10, 2021

Idaho Researchers look for Links between Clovis People & large Mammals on the Snake River Plain


About 13,000 years ago on the banks of the Pleistocene American Falls Lake on the Snake River Plain, large “megafauna” mammals now extinct — such as mammoths, mastodons, camels, short-faced bears, dire wolves & saber-toothed tigers — lived alongside the Clovis people.

However, Clovis artifacts have never been recovered side-by-side with fossil remains of these extinct megafauna mammals, even though they’ve been found near each other.

Charles Speer, an Idaho State University anthropology assistant professor, along with colleagues at the Idaho Museum of Natural History, other universities & soon with ISU students, is engaged in research to document the link between the artifacts of the Clovis people & these extinct animals that populated the area during the same time period.
Charles Speer holds part of a mammoth fossil recovered at the 2018 ISU Archaeology Field School site in the Magic Valley near Kimberly. Next summer, Speer & the school will be working closer to home near American Falls Reservoir.

In a recently published paper on Clovis technology from American Falls on the Eastern Snake River Plain in the journal “North American Archaeologist,” Speer & colleagues detailed the potential for making new scientific findings that can shed light on this period of history in eastern Idaho. This potential includes discovering new information on the area’s climate, animals & people; all of which provides the rationale for thoroughly excavating a site in the area.

“We don’t have a connection in the Snake River Plain between Clovis stone tools, some of the earliest in North America, & the megafauna we have at the time,” Speer said. “We haven’t found any kill, butchering, or scavenging sites where we have the stone tools & animals in the same place. At the American Falls (reservoir) site, it is highly likely that we will find this connection. This next summer during the ISU archaeology field school in June, that is exactly what we are going to be looking for.”

The ISU researchers will be excavating a site down 8 to 10 feet below the surface. “The primary reason we are excavating is that the whole area is in danger of eroding away,” Speer said, noting the group has been tasked by the Bureau of Reclamation to recover as much as they can.

Speer explained that the climate on this portion of the Snake River Plain was likely colder & wetter 13,000 years ago. The climate was affected by the large glaciers to the north extending down from Canada only a few hundred kilometers away. Though the climate was cooler, this area was a magnet for the animals mentioned above, as well as familiar species still making the region home like mule deer, antelope, bison & elk.

“People camped out there, made their tools & hunted the animals. We really just want to make that connection showing they were exploiting these extinct animals because that is a big missing piece,” Speer said.

Studying the climate at the time & potential kill sites can help answer a host of questions about this area’s history.  “We are interested in the animals that died off right when this Clovis culture was at its peak,” Speer said. “We ask questions like ‘did these people kill all these animals, was it climate change or was it both?’ In North America alone, 90 genera of animals over 100 pounds died off during the Clovis period at the close of the Pleistocene 11,700 years ago,” Speer said. This included horses, that flourished when re-introduced 500 years ago by Europeans.

The researchers also are interested in how human beings reacted to climate change during this period, which was right at the end of the Pleistocene period, after which the climate warmed & dried considerably.

In addition, the researchers will be looking for evidence of a culture older than the Clovis living in eastern Idaho.  “Clovis for the longest time was thought to be the oldest culture in North America but know we know it is not,” Speer said. “Researchers in western Idaho have been excavating the Cooper’s Ferry site that is associated with a projectile point style called ‘Western Stemmed’ that is both contemporaneous & potentially older than Clovis. Additionally, they have recovered artifacts several thousands years older which we hope to also discover & fill in the missing pieces with here.”

“We are hoping to see an overlap & connection between the two,” Speer continued, “because we are right on this boundary where to the east you have Clovis in abundance & to the west we have Western Stemmed in abundance, but we don’t have any sites where the two are mixed up. We are also hoping to see the site stretch back in time to 17,000 or 18,000 years ago.”

The researchers will turn over any artifacts found at the site to the Idaho Museum of Natural History, which already has more than 10,000 specimens of megafauna that lived in the area & a collection of Clovis artifacts from the American Falls area.

Saturday, January 9, 2021

Ancient DNA Analysis Reveals Asian Migration & Plague

Ancient DNA Analysis Reveals Asian Migration & Plague - Stockholm University January, 2021

 Northeastern Asia has a complex history of migrations & plague outbursts. That is the essence of an international archaeogenetic study published in Science Advances & lead from the Department of Archaeology & Classical Studies at Stockholm University. Genomic data from archaeological remains from 40 individuals excavated in northeastern Asia were explored in the study.

"It is striking that we find everything here, continuity as well as recurrent migrations & also disease-related bacteria," says Anders Götherström, professor at the Center for Palaeogenetics at Stockholm University & one of the Principal investigators of the study.

The scientists discovered that there were demographic events in the past common for the whole Lake Baikal region. For example, around 8300 years ago there was a migratory event discernible both east & west of Lake Baikal. But there were also events specific for each of the two areas. While the areas west of Lake Baikal provides evidence for recurrent migrations & intense mobility, the areas east of Lake Baikal preserved a long-term continuity for thousands of years, apparently with limited mobility from other areas.

"It is intriguing that our data reveals complex & contrasting patterns of demographic change in one of the least populated regions on earth; including notable gene flow & at the same time a genetic continuity without major demographic changes in the two areas around Lake Baikal", says lead-author Gulsah Merve Kilinc, former postdoctoral researcher at the Department of Archaeology & Classical Studies at Stockholm University & currently Lecturer at Department of Bioinformatics at Hacettepe University in Ankara.

The study also provides some new clues to the history of the Paleo-Inuit groups, the people who inhabited northern Greenland & Canada. While it has been suspected that the so called Belkachi-complex, a cultural group in the Baikal area, played a part in the early history of Paleo-Inuits, it has not been possible to evaluate this in detail. The analyses of remains of an individual associated with the Belkachi cultural-complex, dated to more than 6000 years before present now show that there is an association to a previously published Paleo Inuit (Saqqaq) individual (dated c.4000 yrs BP) on Greenland.

"This is the first genetic evidence of a link between a Neolithic period human group in Yakutia & the later Palaeo-Inuit groups, & this will inspire to new of research on the demographic development", says Jan Storå, Professor at Osteoarchaeological Research Laboratory at the Department of Archaeology & Classical Studies at Stockholm University.

Finally, the study provides new data on the most eastern occurrences of the bacteria Yersinia pestis, the plague. One individual from the Lena basin, dated to c. 3800 years ago, & buried with individuals that proved to be close kin genetically, carried DNA from Yersinia pestis. Also, an individual dated to c. 4400 years ago from the area west of Lake Baikal hosted Yersinia pestis. Interestingly, the population west of Lake Baikal seems to have decreased in size around 4400 years ago, judging from the genomic data.

"Despite a need for more data, our discovery of the decrease in effective population size that coincided with the appearance of Yersinia pestis points to a possible presence of a prehistoric plague - possibly a pandemic. However, this is just as an educated guess which needs to wait for confirmation", says Emrah Krdök, former postdoctoral researcher at the Department of Archaeology & Classical Studies at Stockholm University & currently Lecturer at Mersin University in Turkey.

The article "Human population dynamics & Yersinia pestis in ancient northeast Asia" is published in the scientific journal Science Advances.

Interesting article from 2014...

Mystery Of Paleo-Eskimos, The ‘Hobbits’ Of The Arctic Who Vanished 700 Years Ago, Revealed In Study By Philip Ross 08/30/14 International Business Times

A family photo of an Eskimo mother, father, & son, photographed in Noatak, Alaska, by Edward Sheriff Curtis circa 1929. Modern-day Eskimos are the ancestors of the ancient Dorset culture who were the first people to inhabit the North American Arctic some 5,000 years ago.  Photo: Creative Commons 

Paleo-Eskimos, the ancestors of modern-day Inuit & Native Americans & the earliest people to settle the North American Arctic, were isolated from other cultures for 4,000 years before vanishing around 1300 A.D., DNA analysis shows. The circumstances surrounding the strange disappearance of these early North Americans, known as the Dorset culture, has long been a mystery, but research suggests inbreeding, climate change or competition with other populations of hunters could have played a role, a study led by the University of Copenhagen & published Friday in the journal Science found.

“The Dorsets were the Hobbits of the eastern Arctic -- a very strange & very conservative people who we’re only just getting to know a little bit,” anthropologist William Fitzhugh, director of the Arctic Studies Center at the Smithsonian’s National Museum of Natural History & a co-author of the study, told the Washington Post. Because the Dorset people lacked sophisticated weaponry like bows & arrows, “they were, in a sense, sitting ducks,” he said.

Researchers studied the remains of some 169 Paleo-Eskimos discovered in northern Greenland, including their hair, bones & teeth. Scientists extracted mitochondrial DNA from the remains & compared it to genetic samples from modern people living in Greenland, northern Canada, the Aleutian Islands & Siberia. They found the Dorset people were genetically isolated from other populations & showed signs of inbreeding.

The research provides the clearest picture yet of how the North American Arctic was populated some 5,000 years ago. "Since the 1920s or so, it has been heavily discussed what is the relationship between these cultural groups," senior author Eske Willerslev of the Natural History Museum of Denmark, which is part of the University of Copenhagen, told the BBC. "All kinds of hypotheses have been proposed. Everything from complete continuity between the first people in the Arctic to present-day Inuits, [while] other researchers have argued that the Saqqaq & the Dorset & the Thule are distinct people."

Exactly who first populated the Arctic has long been debated. Scientists know  three broadly grouped cultures all occupied the northernmost parts of North America in the past few thousand years. They were the Saqqaq, who occupied the region until about 2,500 years ago, followed by several Dorset culture & then the Thule, the ancestors of modern-day Inuit, from about 1,000 years ago, the BBC said.

Because the Dorsets do not share any genetic similarities with people in the Arctic today, researchers concluded the population disappeared rather suddenly. Climate change could have something to do with it, scientists say. Regional temperature shifts could have strained the Dorsets food sources -- ox, seal & reindeer.

"When you're dealing with sea ice, just a few degrees can be transformative,” Todd Disotell, a professor of anthropology at New York University, told the New York Times. “Three bad winters in a row where you can't hunt seals, & you're in trouble.”