This is obviously important and cleanly proves the existence of a single founder population. We still had ample hybridization coming off that founder population but only much later when it would remain a minority effect. That founder population did come out of the Bering area and off course migrated along the sea coast and then eventually inland until all the continents of North and South America was populated.
This certainly took place as early as 20,000 BP and possibly and plausibly much sooner.
Much later other came and that includes a substantial injection of Europeans during the Bronze Age.
DNA Analysis Shows That Native American Genealogy Is One of the Most Unique in the World
http://www.whitewolfpack.com/2014/08/dna-analysis-shows-that-native-american.html
Native Americans Descended From A Single Ancestral Group, DNA Study Confirms
The suppression of the Native Americans and the decimation of their
culture is a black page in the history of the United States. The
discrimination and injustices towards this ancient race, which had lived
on the American continent long before the European conquerors came to
this land, are still present to this day despite the efforts of
different groups and organizations trying to restore the justice.
The destruction of their culture is one of the most shameful aspects of
our history, the extent of the damage that was done is still being
down-played and denied entry into textbooks and history-lessons to this
day.
The origin and history of the Indigenous Peoples of the Americas have
been studied for years by researchers from different countries, and a
recent DNA study showed that the genealogy of the western aboriginals is
one of the most unique in the world.
The question of whether Native Americans derived from a single Asian
population or from a number of different populations has been a subject
of research for decades. Now, having compared the DNA samples from
people of modern Native American and Eurasian groups, an international
team of researchers concluded on the validity of the single ancestral
population theory.
The study follows up on earlier research that found a unique variant of a
genetic marker in the DNA of modern descendants of Native Americans.
“While earlier studies have already supported this conclusion, what’s
different about our work is that it provides the first solid data that
simply cannot be reconciled with multiple ancestral populations,” said
Kari Britt Schroeder of the University of California, one of the authors
of the study.
As a result of the previous research, the so-called “9-repeat allele”
(or variant) was found in all of the 41 Native American and Asian (from
the western side of the Bering Strait) populations that were sampled. At
the same time, the allele was absent in all 54 of the Eurasian, African
and Oceanian groups that were also sampled in the study.
The researchers supposed that the distribution of the allele was due to
the fact that all these ethnic groups (modern Native Americans,
Greenlanders and western Beringians) derived from a common founder
population, which had been isolated from the rest of the Asian continent
thousands of years prior to their migration to the Americas.
This explanation was persuasive enough; however, there was no strong
evidence to support it. There were two other plausible versions to
explain the distribution of the 9-repeat allele among the modern
descendants of Native Americans.
If the 9-repeat allele had originated as a multiple mutation, its
presence in the Americas would not suggest common ancestry. Thus, if
there had been more than one ancestral founder population and the
9-repeat allele had been present only in one of them, it could possibly
have passed to the other ethnic groups and spread among them. If there
also had been a second, beneficial allele located very close to the
9-repeat allele, it would certainly have been carried into new
populations. At the same time, long stretches of DNA surrounding the
9-repeat allele would be carried along with the beneficial allele due to
the mechanisms of natural selection.
In order to check the validity of this hypothesis, researchers led by
Noah Rosenberg of the University of Michigan analyzed DNA samples from
people from Asian, Native American, Greenlandic and two western
Beringian populations, and found that all the samples with the 9-repeat
allele had a distinct pattern of base pairs in short stretches of DNA.
As Schroeder noted, “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. 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.”
These findings also excluded the multiple mutations theory, because in
this case there would have been myriad DNA patterns surrounding the
9-repeat allele.
“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,” concluded Schroeder. (Source)
The results of the study were published in the journal Molecular Biology and Evolution.
Journal Reference:
Schroeder et al. Haplotypic Background of a Private Allele at High
Frequency in the Americas. Molecular Biology and Evolution,
From Science Daily
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