Posted on 04/29/2009 6:13:15 AM PDT by Pharmboy
For two decades, researchers have been using a growing volume of genetic data to debate whether ancestors of Native Americans emigrated to the New World in one wave or successive waves, or from one ancestral Asian population or a number of different populations.
Now, after painstakingly comparing DNA samples from people in dozens of modern-day Native American and Eurasian groups, an international team of scientists thinks it can put the matter to rest: Virtually without exception the new evidence supports the single ancestral population theory.
Our work provides strong evidence that, in general, Native Americans are more closely related to each other than to any other existing Asian populations, except those that live at the very edge of the Bering Strait, said Kari Britt Schroeder, a lecturer at the University of California, Davis, and the first author on the paper describing the study.
While earlier studies have already supported this conclusion, whats different about our work is that it provides the first solid data that simply cannot be reconciled with multiple ancestral populations, said Schroeder, who was a Ph.D. student in anthropology at the university when she did the research.
The study is published in the May issue of the journal Molecular Biology and Evolution.
The teams work follows up on earlier studies by several of its members who found a unique variant (an allele) of a genetic marker in the DNA of modern-day Native American people. Dubbed the 9-repeat allele, the variant (which does not have a biological function), occurred in all of the 41 populations that they sampled from Alaska to the southern tip of Chile, as well as in Inuit from Greenland and the Chukchi and Koryak people native to the Asian (western) side of the Bering Strait. Yet this allele was absent in all 54 of the Eurasian, African and Oceanian groups the team sampled.
Overall, among the 908 people who were in the 44 groups in which the allele was found, more than one out of three had the variant.
In these earlier studies, the researchers concluded that the most straightforward explanation for the distribution of the 9-repeat allele was that all modern Native Americans, Greenlanders and western Beringians descend from a common founding population. Furthermore, the fact that the allele was absent in other Asian populations most likely meant that Americas ancestral founders had been isolated from the rest of Asia for thousands of years before they moved into the New World: that is, for a period of time that was long enough to allow the allele to originate in, and spread throughout, the isolated population.
As strong as this evidence was, however, it was not foolproof. There were two other plausible explanations for the widespread distribution of the allele in the Americas.
If the 9-repeat allele had arisen as a mutation multiple times, its presence throughout the Americas would not indicate shared ancestry. Alternatively, if there had been two or more different ancestral founding groups and only one of them had carried the 9-repeat allele, certain circumstances could have prompted it to cross into the other groups and become widespread. Say that there was a second allele one situated very close to the 9-repeat allele on the DNA strand that conferred a strong advantage to humans who carried it. Natural selection would carry this allele into new populations and because of the mechanics of inheritance, long stretches of DNA surrounding it, including the functionless 9-repeat allele, would be carried along with the beneficial allele.
To rule out these possibilities, the research team, which was headed by Noah Rosenberg at the University of Michigan, scrutinized DNA samples of people from 31 modern-day Asian populations, 19 Native American, one Greenlandic and two western Beringian populations.
They found that in each sample that contained the 9-repeat allele, short stretches of DNA on either side of it were characterized by a distinct pattern of base pairs, a pattern they seldom observed in people without the allele. If natural selection had promoted the spread of a neighboring advantageous allele, we would expect to see longer stretches of DNA than this with a similarly distinct pattern, Schroeder said. And we would also have expected to see the pattern in a high frequency even among people who do not carry the 9-repeat allele. So we can now consider the positive selection possibility unlikely.
The results also ruled out the multiple mutations hypothesis. If that had been the case, there would have been myriad DNA patterns surrounding the allele rather than the identical characteristic signature the team discovered.
There are a number of really strong papers based on mitochondrial DNA which is passed from mother to daughter and Y-chromosome DNA which is passed from father to son that have also supported a single ancestral population, Schroeder said. But this is the first definitive evidence we have that comes from DNA that is carried by both sexes.
Other authors of the study are David G. Smith, a professor of anthropology at UC Davis; Mattias Jacobsson, University of Michigan and Uppsala University in Sweden; Michael H. Crawford, University of Kansas; Theodore Schurr, University of Pennsylvania; Simina Boca, Johns Hopkins University; Donald F. Conrad and Jonathan Pritchard, University of Chicago; Raul Tito and Ripan Malhi, University of Illinois, Urbana-Champaign; Ludmilla Osipova, Russian Academy of Sciences, Novosibirsk; Larissa Tarskaia, Russian Academy of Sciences, Moscow; Sergey Zhadanov, University of Pennsylvania and Russian Academy of Sciences, Novosibirsk; and Jeffrey D. Wall, UC San Francisco.
The work was supported by NIH grants to Rosenberg and Smith and an NSF Graduate Research Fellowship to Schroeder.
Please have your husband comment on these findings when he can...
That seems plausible. I was wondering how populated that area was to begin with.
Agreed. That’s why I put “American Indian” in the key words. As I understand, it is how the aboriginal Americans prefer to be referred to.
I have not kept up with the more modern ideas on this. And of course, now with the ability to track DNA it’s completely changed how we can look at it. I find it interesting tho.
Not that surprising. Genetic marker science had already shown by the early 90’s that all modern humans came from one WOMAN. Then 10 years later those same scientists showed that all humans also came from one MAN. Essentially, it was genetic confirmation of the Adam and Eve story, really.
So I guess no DNA matches with any modern day descendants or relatives of those Israelite tribes exiled to Assyria around 2700 years ago?
Extensive testing and historical research shows my peoples came to America over the air bridge in a 707, circa 1968.
Genesis 11:8&9, says that the Lord SCATTERED the folk over the face of the earth.
Verse 4 says...the whole earth.
"The oldest human remains found in the Americas were recently "discovered" in the storeroom of Mexico's National Museum of Anthropology. Found in central Mexico in 1959, the five skulls were radiocarbon dated by a team of researchers from the United Kingdom and Mexico and found to be 13,000 years old. They pre-date the Clovis culture by a couple thousand years, adding to the growing evidence against the Clovis-first model for the first peopling of the Americas."
"Of additional significance is the shape of the skulls, which are described as long and narrow, very unlike those of modern Native Americans
Read Red Earth, White Lies: Native Americans and the Myth of Scientific Fact by Vine Deloria. At 15 bucks or so, it's a much better investment than some NIH or NSF grant, and also more likely correct.
ML/NJ
Salving the wound? ;-)
You mean like this small remnant East Cost tribal group of Colonial Dames (and Dude) who look suspiciously to be of European origin to me:
Oh I love the dress on the right.....
Ping for truth!
This study does not really dispel evidence of other immigrations across the Pacific and Atlantic.
Yes...that would be great. And what about Kennewick Man?
Same here.
Sometimes I check the little Native American box just to annoy the HR people.
What? No Hebrew blood? LOL
This study seems to support Greenberg’s Amerind idea about there being one basic tongue from which all the others (except two cases) descend.
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