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Earliest Americans Seen as More Diverse

And this is the July 31st article. thanks Susan G. for providing the reference:
Susan Marsh

Earliest Americans Seen as More Diverse
By Guy Gugliotta
Washington Post Staff Writer
Tuesday, July 31, 2001; Page A01
Ancient peoples only loosely related to modern Asians crossed the Arctic land bridge to
settle America about 15,000 years ago, according to a study offering new evidence that the
Western Hemisphere hosted a more genetically diverse population at a much earlier time
than previously thought.
The early immigrants most closely resembled the prehistoric Jomon people of Japan and
their closest modern descendants, the Ainu, from the Japanese island of Hokkaido, the
study said. Both the Jomon and Ainu have skull and facial characteristics more genetically
similar to those of Europeans than to mainland Asians.
The immigrants settled throughout the hemisphere, and were in place when a second
migration -- from mainland Asia -- came across the Bering Strait beginning 5,000 years ago
and swept southward as far as modern-day Arizona and New Mexico, the study said. The
second migration is the genetic origin of today's Eskimos, Aleuts and the Navajo of the
U.S. southwest.
The study in today's edition of the Proceedings of the National Academy of Sciences adds
new evidence to help settle one of anthropology's most contentious debates: Who were the
first Americans? And when did they come?
"When this has been done before, it's been done from one point of view," said University
of Michigan physical anthropologist C. Loring Brace, who led the team of researchers from
the United States, China and Mongolia who wrote the new report. "We try to put together
more dimensions."
For decades, anthropologists held that the Americas were populated by a single migration
from Asia about 11,200 years ago -- the supposed age of the earliest of the elegantly
crafted, grooved arrowheads first found in the 1930s in Clovis, N.M.
By the end of the 1990s, however, the weight of evidence had pushed back the date of the
first arrivals several thousand years. A site at Cactus Hill, near Richmond, may be 17,000
years old.
In Chile, scientists excavating a 12,500-year-old settlement at Monte Verde have found
evidence of a human presence that may extend as far as 30,000 years.
But as the migration timetable slipped, additional questions and controversies have
arisen. The 1996 discovery in Kennewick, Wash., of the nearly complete skeleton of a
9,300-year-old man with "apparently Caucasoid" features stimulated interest in the
possibility of two or more migrations -- including a possible influx from Europe.
The new study attempted to answer this question by comparing 21 skull and facial
characteristics from more than 10,000 ancient and modern populations in the Western
Hemisphere and the Old World.
The findings provide strong evidence supporting earlier work suggesting that ancient
Americans, like Kennewick Man, were descended from the Jomon, who walked from Japan to the
Asian mainland and eventually to the Western Hemisphere on land bridges as the Earth began
to warm up about 15,000 years ago at the end of the last Ice Age.
Brace described these early immigrants as "hunters and gatherers" following herds of
mastodon first into North America, and eventually spreading throughout the hemisphere.
Because the North -- in both Siberia and Canada -- was still extremely cold, only a
limited number of people could make the trek and survive.
So immigration slowed, Brace said, for about 10 millennia. Then, about 5,000 years ago,
agriculture developed on mainland Asia, enabling people to grow, store and carry food in
more inhospitable areas. Movement resumed, but the newcomers were genetically Asians --
"distinct racially" from the first wave, Brace added.
The second wave spread across what is now Canada and came southward, cohabiting with the
earlier settlers and eventually creating the hybrid population found by the Spaniards in
the 15th century.
While many researchers agree on the likelihood of two migrations, both their timing and
origin are matters of dispute. Brace's team suggests that both movements occurred after
the last Ice Age began to moderate between 14,000 and 15,000 years ago.
But University of Pennsylvania molecular anthropologist Theodore Schurr said genetic data
in American populations suggest that humans may have been in the Western Hemisphere much
earlier -- 25,000 to 30,000 years ago.
This would mean that the first wave came before the "glacial maximum," between 14,000 and
20,000 years ago, when the Ice Age was at its fiercest and "human movement was practically
impossible," Schurr said. "Were there people here before the last glacial maximum?" he
asked. "The suggestion is, 'Yes.' "
To date, archaeological evidence for settlements earlier than 20,000 years ago is almost
nonexistent, but Schurr suggested that researchers may have been reluctant to explore
layers older than Clovis because of Clovis's predominance in the scientific community.
Still, neither Brace nor Schurr was prepared to endorse the view propounded by the
National Museum of Natural History's Dennis Stanford: that at least some immigrants may
have come from Ice Age Europe.
"The environment in Europe was so harsh that land mammals were very rare," Stanford said,
"so they went to the beach." If these ancient people had boats, it was natural that they
should go to sea to look for food, and edging further north and west, they would
eventually reach the fish-rich Grand Banks. "From there they move right down the east
coast" of North America, he said.
Stanford bases his theory on the presence of Clovis-like artifacts on the Iberian
Peninsula around 20,000 years ago, and that there are more Clovis points in the eastern
United States than in the West.
Also, he notes that genetic evidence links eastern Native American populations with
ancient Europeans, but not with Asians.
He suggests the migrants moved on Ice Age land bridges from Iberia to Wales and eventually
to Ireland, then set sail to hunt the seals and fish on the rim of the polar ice pack.
They edged further and further west, and when they reached North America "they probably
didn't even know they were there."
 2001 The Washington Post Company

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