Wednesday, April 29, 2009

Native Americans Descended From a Single Ancestral Group, DNA Study Confirms

This is interesting. Native Americans Descended From a Single Ancestral Group, DNA Study Confirms April 28, 2009 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 [in general? What does THAT mean?], 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, what’s 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. Rest of article.
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Are the authors of this DNA study saying that the archaeologists who support much older evidence of human occupation in North and South America are full of baloney? There is a lot of archaeological evidence pointing to MUCH older origins for humans in North and South America than a Bering Strait crossing supports. Who's right? The archaeologists? Was man here as far back as 50,000 years ago, 30,000 years ago or 14,000 years ago? Archaeologists claim evidence of human occupation for each of these dates - and dates in-between. For sake of argument, are all of the artifacts identified as Clovis, a particular style of artifact and date-range well-established and generally accepted in the archaeological community as correct, WRONG by 3,000 or more years? Or are the DNA scientists correct, pointing to a single population cross Bering Strait 11,000-10,000 years ago as being the ONLY ancestors of ALL Indian populations in North, Central and South America? Did absolutely everyone who arrived on the shores of North, Central and South America before those who crossed the Bering Strait die out, leaving absolutely no trace of their DNA in today's Indian populations? How else can the archaeological evidence be explained? Are ALL of the archaeologists and ALL of their accumulated evidence wrong? If archaeological evidence supports the existence of settlers in North and South America that predate DNA evidence for the ancestors of the current Native Americans, then aren't the descendants of those earlier deceased original settlers the REAL heirs to claims for rights to North, Central and South American real estate, etc. etc.? And would not the claims of the heirs of those earlier settlers trump the claims asserted by present Native American tribes claiming sovereignty and property rights, etc. etc. in North, Central and South America? If DNA evidence conclusively establishes that today's Native Americans became the dominant aborginal culture - rather like Europeans became the dominate culture during much later migrations to the New World, how can today's Indian tribes, aboriginals, First Nations, whatever they label themselves, claim special privilege when the DNA evidence shows, against the archaeological evidence, that when they arrived they MUST have wiped out all earlier settlers? Under common law, which the United States follows, wouldn't those inheritance rights pass to the ancestors of the first settlers who arrived on those shores? And just who were those first settlers? Some say they were Europeans (on the east coast); on the west coast, some say they were possibly of the Jomon culture, from Japan. Given the current state of archaeological evidence, and if this latest study of DNA evidence is correct, today's Native Americans have no right to say they were here first. It's clear they were not here first. What remains to be determined is just who was here first. Will it end up that Japan - or France - or Spain - files a claim to large chunks of the United States? Well, you can see what a can of worms this might open up. So, DNA people, before stating with such certainty that this is exactly what happened and there are no other probable explanations, my suggestion is that you take a look at the archaeological evidence compiled to date, and then wait for more sophisticated techniques of genetic analysis to be developed and view your evidence against those techniques and the entirety of the rest of the existing evidence, before you says this is the absolute truth and this is what happened.

5 comments:

Kari Schroeder said...

Hi Jan,
I am interested in some of the comments on our research which have surfaced on the internet in the past 24 hours. I don't usually participate in the discussion, but I feel some comment here is necessitated to stem the perpetuation of misinformation. I understand that you probably don't have access to our published article (I would be happy to send it to you by email - kbschroeder@ucdavis.edu), and I'm sure you realize that, while the press release is an excellent summary of our research, as with any press release, it was concisely written for a very broad audience. Most importantly, our research is not relevant to how Native Americans arrived in the Americas (eg Bering Land Bridge and ice-free corridor, coastal migration), and we do not make this claim in either the article or press release. That both languages and genetic variants are shared by people on both side of the Bering Strait is not a new finding and does not mean that a Bering Land Bridge was used. While our article presents results from an attempt to date the time at which all carriers of the 9-repeat allele last shared a common ancestor (which is not the same as dating the migration), the error around the date gives us a range from ~7,000 to 40,000 years ago - which is compatible with any number of complex scenarios from the archaeological data. Lastly, modern genetic data cannot tell us about the biological affinities of the oldest remains found in the Americas. The two ancient DNA studies that are older than about ~10,000 years both show that the lineages these individuals carried are present in modern Native Americans. Lastly, and most importantly, the vast majority of archaeological and genetic data DO NOT substantiate claims that Native Americans came form Europe. I would be happy to discuss any of these points with you in more detail.
-Kari Schroeder

Lǔkèsī Bādùn said...

clearly, the author of the original blog post (jan?) did not read the article in MB&E. but hey, blatant ignorance is an outstanding soap-box..

Jan said...

Hi Kari,

Thanks for your post. I will contact you regarding receiving a copy of the full article. Not being an expert, I doubt I will be able to make much sense out of any technical detail it contains. That's why reading press releases and articles in "popular" science and history magazines that are geared toward the average person are crucial to educating me and everyone else about what's going on in your field and about scientific endeavors in general.

I have some comments and more questions after reading your post, and I will go into more detail about why I wrote what I did last night. I hope to get back to you later tonight with those.

As for Lukesi Badun's comment, I do not think that asking questions and raising issues and expressing an opinion mean that I am an ignorant person, particularly when doing so can encourage dialog and lead to clarification of matters I find of interest; quite the opposite, actually, since it demonstrates intellectual curiosity. I am open to reasoned discussion and examination of the evidence from many different points of view. If you have something helpful to add to the conversation, then please do so. If not, then don't read here any further since you find me so offensive.

Lǔkèsī Bādùn said...

jan. ignorance doesn't mean stupid. it means lack of information. you lack information. missing information is not offensive in itself, nor is this a judgment of character. but the world's strongest opinions, the loudest voices, and the most virulent reactions are powered by insufficient information. the more you know, the less clear it is. and it seems you're perfectly willing to gather enough information to see the world's spectrum in grey truth, rather than political black and white. by making public pronouncements in ignorant binaries, you invite criticism. that IS reasoned discussion, and we're in it...

Jan said...

Hi Kari,

I'm back. Thanks again for the additional information and explanation you have provided. It is most illuminating and I see where I went wrong - those assumptions that one makes, oy! I've pointed my finger more than once at others who also make assumptions on what I've deemed insufficient evidence, only to fall into the same trap. Mea culpa!

That being said, I am going to attempt to mount a defense for what I wrote last night. I have not read the full report (I'm emailing you privately for that). I was responding to what I read last night in the press release.

It was stated (in part) in the press release: “Virtually without exception the new evidence supports the single ancestral population theory.… and

““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, what’s 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.”

I would like to point out that in the press release, no dates were given. Based upon my understanding of the contents of the press release, I think it was reasonable to draw the inference that those people on the east side of the Bering Strait (Native Americans) with the identical “9-repeat allele,” as the people on the west side of the Bering Strait, were the descendants of the people whose ancestors crossed over from the west side to the New World – and, since the location of the Bering Strait to both populations was a no-brainer – it was logical for me to assume that the people crossed over the Bering Strait to the New World during the relatively short time the land-bridge was open. Of course, other people can (and did) disagree with what I concluded was being inferred. (I probably didn't frame it in as careful terms as I should.)

In my further defense, I point to this quote from the press release:

“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.”

Obviously I’m no expert. But I do recall reading something like – and I’m probably putting this very badly – as best I understand it, there is a regularity of occurrence of mutations in DNA over time, and that this mutation rate has been calculated; and the mutation rate is relatively far apart, in terms of thousands of years. I interpreted what was written in the press release to mean that not enough time had elapsed since migration of the people with the 9-repeat allele mutation across the Bering Strait from the west for genetic mutations to occur in the population now residing on the east side of the Bering Strait. (I suppose that was poorly said.)

It was pointed out in your post – and thanks again for the clarification and additional illuminating information – that the date range for which all carriers of the 9-repeat allele last shared a common ancestor was from 7,000 to 40,000 years ago. Having this additional information today, I can see where I was off base in some of what I wrote last night. However, I do have a question about this quote from the press release:

“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.”

What does that mean in terms of the other one plus people out of three who do not have the variant? Is this significant? Am I missing something?

I’d also like some clarification, if you would be so kind, in language geared to “DNA for Dummies 101” of your comment: “”…modern genetic data cannot tell us about the biological affinities of the oldest remains found in the Americas. The two ancient DNA studies that are older than about ~10,000 years both show that the lienages these individuals carried are present in modern Native Americans.” Is this a correct interpretation: Modern DNA cannot tell us about the DNA of the past, but past DNA can tell us about present DNA? Er, obviously I’m not getting this, because that doesn’t make sense to me. What did you mean? What have I missed?
Does not modern DNA carry some signatures (? probably the wrong word) of past DNA? Is not DNA traceable both ways - past to present and present to past?

I would like to point out that I did not anywhere say in my post last night that I thought people from Europe are the ancestors of today’s Native Americans. I said that some people suggested they might be. I didn’t base this statement on nothing. I have read several news articles over the past 3-4 years exploring such an hypothesis, for instance linking Aurignacian stone points to Clovis stone points.

In summary, I do not think that the questions I asked were wrong, given my assumptions. I freely admit that those assumptions were mistaken, but they were based upon incomplete information. That being said, I think questions remain, but they are outside the scope of your research.

Thanks for responding.

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