DNA indicates Eurasian roots for Native Americans, new study says? Really? Like we learn this in school all ready? Hello Ice Bridge Anyone?

Posted January 19, 2004 http://histclo.com/chron/na/na-ice.html

Native Americans Origns

The Native American people are primarily descended from Siberian peoples who crossed the Bearing Straits. Archeologists for some time have been convinced that Natve Americans are of Asiatic origins that migrated from Siberia. The Native American people are primarily descended from Siberian peoples that crossed the Bearing Ice Bridge created by the Ice Age. They were nomadic hunter-gatherers migrated to the American continent over a Bearing Sea land-ice bridge. This accepted by the scientific community. Virtually everything else about Native Americans is a matter of dispute. The history of native Americans is hotly debated by archeologists, anthropologists, geneticists, and linguists. Joining the debate are Native Americans who have many legitimate grevinces with archeologists. Modern DNA studies have confirmed the Asiatic origins of modern Native Americans. There is a lingering debate as to other peoples who may have also reached the Americas. While Native Americans are clearly of Asiatic origins, just when they crossed the Bearing Sea Ice Bridge and how they moved south is of intense academic debate.

Bering Sea Crossing

The Siberians who migrated to North America were nomadic hunter-gatherers who crossed the Bering Land Bridge. This is one of the few events that archeologists agree about. During the Ice Age sea levels were lower, much lower. So much water was tied up in the Northern Hemisphere ice cap, that sea levels may have been an incredible 100-150 meters lower than today. This created a land bridge over what is now the shallow but forbidding Bearing Straits. Prescisely when this crossing took place, however, is a matter of considerable controversy. For years Archeologists based on the Clovis First theory dated the crossing at about 13,500 years ago. This was the time when the glacial ice of the Ice Age was believed to have receeded and a ice free-corridor appeared south from Alaska into the Noth American heartland. There is now, however, considerble disagreement among Native American specialists as to just when these crossings began. how they were made, and how long they continued. Some scientists now believe that Ice Age people arrived in North America over the Bering Sea land bridge much earlier, perhaps 20,000-30,000 years ago or even earlier. Archeologists for the most part clung to Clovis First. Other specialists, however, raised some chincks in the Clovis First orthodoxy. Preliminary DNA studies suggest that these migrations took place in multiple, perhaps three waves. These estimates are based on recent DNA studies assessing when Asians and Native Americans diverged genetically. Not all researchers working with DNA agree as to the dates involved. Some also suggest that it was about 15,000 years ago. One study suggest that the first crossing was made by extrenmely small groups, perhaps only 10-20 people. Then the linguists chimed in to the debate. They noted an incredible linguistic diversity, far greater than the Old World. This suggested a much earlier initial crossing than estimated by the Clovis First theorists. These new contributors to the subject were not invested in Clovis First like the archeological community.  


Posted in 2013?

The genetic analysis of a 24,000-year-old arm bone from an ancient Siberian boy suggests that Native Americans have a more complicated ancestry than scientists realized, with some of their distant kin looking more Eurasian than East Asian.

The new study, published online Wednesday in the journal Nature, represents the oldest genome of a modern human ever fully sequenced.

Modern-day Native Americans share from 14 to 38 percent of their DNA with the Siberian hunter-gatherers — who are not closely related to East Asians — with the remainder coming from East Asian ancestors. Most scientists have thought that the first Americans came only from the East Asian populations.

“If you read about the origins of Native Americans, it will say East Asians somehow crossed the Bering Sea,” said study author and evolutionary biologist Eske Willerslev at Copenhagen University. “This is definitely not the case — it’s more complex than that.”

It isn’t known where or when the meeting of the two peoples happened, but a likely location could be Beringia, the region surrounding the current gap between Alaska and Siberia. Although 
presently occupied by the Bering Strait and its surrounding waters, the glaciers of roughly 20,000 years ago locked up much of the earth’s water, exposing a land bridge between the two continents.
The prehistoric crossroad provided an easy way for people, animals and plants to spread.

Originally excavated in the 1950s, the remains of the boy had been tucked away in the bowels of a museum in St. Petersburg. He was about 3 when he died, and he was buried with a variety of “grave goods,” including a swan figurine and an ivory pendant.

When Willerslev sequenced the DNA from the boy’s upper arm bone, he thought the results were a mistake: It said the boy belonged to a lineage commonly found among Europeans, but not in East Asians.

“We put the study on hold for a year because I thought it was contamination,” Willerslev said.
They tried again, this time digging deeper and looking at the Y chromosome. It and the rest of the genome told the same story: The boy had links to present-day western Eurasians and Native Americans, but not East Asians.

They also sequenced a more recent Siberian adult whose DNA wasn’t as well preserved, and they got similar results.
“They were members of a really cosmopolitan group that probably reflect early modern humans leaving Africa and spreading into central Asia,” said study author Kelly Graf, a Texas A&M anthropologist.

Their results support fossil evidence from early Paleo-Indian humans, such as a well-preserved skeleton known as Kennewick man found in Washington state. Dated to about 9,000 years old, he has facial features that don’t look East Asian but rather somewhat Caucasian — a mystery found replicated in other skulls.

The fact that the first Americans were already mixed to begin with could answer these controversies, Willerslev said. Any Western Eurasian genetic signatures found in Native Americans today were previously attributed to post-1492 colonial mixing with Europeans.
“Maybe it has much deeper roots — from Siberia, not Europeans coming over in their boats,” Graf said.

Graf and Willerslev said their next step is to gather DNA samples of early American populations to find evidence of those proto-Eurasian roots in the New World.

http://www.washingtonpost.com/national/health-science/fossil-indicates-eurasian-roots-for-native-americans/2013/11/20/2777ac24-51fa-11e3-a7f0-b790929232e1_story.html?tid=pm_national_pop