Who We Are and How We Got There

SnakHistory at 30,000 feet: The Big Picture

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Who We Are and How We Got There

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apr 30, 2018, 12:02am

Jumping ahead to Chapter 7: In Search of Native American Ancestors I was pleased to discover that my boyhood hunch about migration patterns from Asia into North and South America is being confirmed by recent DNA studies ... that is, the long-held belief that the first immigrants to the Western Hemisphere arrived via an ice-free glacial gap that stretching from Alaska to the Midwest, a gap formed only 12,000+ years ago, may well have not been the first immigrants to the New World.

As a pre-teen boy growing up in previously glaciated parts of the Northern Plains, I found it difficult to believe that the complex civilizations of South America could have evolved in such a relatively short time. Studies of the Quaternary Glacial period told me that there were three to five interglacial periods ... not merely the most recent ... during which people from Asia could have easily arrived in North and South America biy walking ... long before that last 12,000+ year period. As a boy I had only an intuitive, common-sense hunch about these things ... but now ...

DNA research of several isolated tribes in the Amazon Basin demonstrates that, yes, they crossed over from Asia as much as 26,000 years ago. Difficulties with these South America tribes has made expanded research into the time period difficult, but genetically those tribes are most closely related to Australians, New Guineans and ...Andamanese ... and not to most Native Americans, whose ancestors came from Siberia.

Redigeret: apr 30, 2018, 2:58pm

It’s fascinating stuff. This book is up next for me, so I can’t comment on Chapter 7 per se. I have followed these developments casually, and had the impression that the story is emerging to be much more complicated than previously thought. But perhaps it is going too far to describe this as established consensus? Some researchers argue that the small indigenous South American populations from whose genomes the data come have very low genetic diversity. Thus they are much more subject to genetic drift than larger more diverse populations and there is a greater likelihood that genetic affinities to other populations such as indigenous Australians could be due to chance. But in any case the argument for earlier migration has been building for several decades now.

In case anyone is imagining Polynesian-type craft escorting the ancestors of Aboriginal Australians across the Pacific to the shores of western South America: the idea under consideration is that the ancestors of indigenous Australians, New Guineans, etc and these South American groups represent a population that once lived in Asia but no longer persist there. This group is postulated to have had descendants that migrated south toward New Guinea and Australia, and north, across Beringia and then south eventually arriving in South America.

Truly exciting to recognize how much of our history remains accessible if only we are able to uncover and interpret it

apr 30, 2018, 9:58am

>1 Rood:

"... and not to most Native Americans, whose ancestors came from Siberia."

They all came through Siberia, did they not ? It is a question of timing I suppose with dna of the people crossing the bridge - 25000 years ago more akin to other travelers of that period ( NG & Australia ) rather than more recent wanderers.

apr 30, 2018, 12:05pm

>3 Macumbeira: This is what I am saying, above.

apr 30, 2018, 1:04pm

I know, we can't say it enough !

apr 30, 2018, 2:59pm

>5 Macumbeira: Agreed. People should be shouting it from the rooftops!

apr 30, 2018, 3:31pm

The last thing we need is another west to east Thor Heyerdahl !
Thor's theory sucks but his sailing trip was one of a kind.

maj 13, 2018, 10:35pm

I have to say, I am loving this book. Such a rich topic. I have bored my entire family trying to share the thrill at the dinner table. There is stuff in here that you just want to shout from the rooftops: “Have you heard? Do you know about this?!”

Redigeret: maj 22, 2018, 9:07pm

Wow, that is a seriously important find. So close to the departure from Africa, often given as 70000-50000 years ago. How close are these people to that root? Or to the root of the former “ghost population” of ancient North Eurasians, whose descendants’ genome, if I’m not mistaken, is only known to 24,000 years ago? Excited to see that genome, assuming they can extract DNA from them.

maj 30, 2018, 12:42pm

I've just finished the book, and am blown away by the discovery of ghost populations in the not so very deep history of the populations of pretty much every continent. I look forward to the picture being filled out as the field matures.

I'll take the opportunity to add the touchstone: David Reich, Who we are and how we got here : ancient DNA and the new science of the human past

jul 10, 2018, 3:23pm

I finished the book. Tremendous and important!

aug 7, 2018, 2:26pm

Got the book a while ago but just started reading a few days since. Got to say I found even the first chapter quite heavy going even though I have a science background (in the distant past). I'm getting something out of the Neanderthals and Denisovans and I think I'll plough on and then come back. Sometimes I think the early bits make more sense when you know where they're leading.

aug 24, 2018, 12:57pm

Yes, it’s rather staggering that out of five samples with substantial Denisovan ancestry, one is a hybrid. We need more dna, and some correlated actual fossil materials would be great. But it certainly suggests that the mixings were not uncommon.

aug 24, 2018, 12:58pm

>13 PossMan: I felt the book was wonderful for the interest and magnitude of the discoveries it describes. Less so as a book per se, ie as a piece of writing.

okt 26, 2018, 5:13pm

A fabulous book that introduces the public to the changing understanding of prehistory thanks to the study of ancient DNA. I knew that this breakthrough was coming, and I am delighted to have lived long enough to sample its first fruits. David Reich can be proud of this book and his pioneering work in the field
The point that made the most impression on me is the persistence (one wonders if permanence is the more adequate term) of violence throughout human history / prehistory.
A recent book on violence that I also found interesting is "The Great Leveler: Violence and the History of Inequality", by Walter Scheidel. Reich underlines how violence increases inequality, while Scheidel shows how violence, mass violence, has (at times) lessened inequality.
Also, of course, the discussion of migrations in Reich's book was fascinating and important too. The information on the Indo-Europeans is really eye-opening. There were a lot of theories regarding the Indo-Europeans, now we have much better evidence than ever before.
The notion that "race-mixing" isn't new, but goes back many thousands of years is also important. Mass Migration, like violence, seems to be a persistent fact of human history.

okt 27, 2018, 2:31pm

>17 pomonomo2003: Hey Joe! Long time no speak! Glad you loved this book as I did. I too am thrilled that I am alive while the insights from current genetic analytic tools are becoming clear. Reich is of course to be commended for the significance of his research. But the book is an achievement in that this material is crying out for a scientist/communicator, because the importance of these insights to people in general in comprehending the human past in new ways is hard to overstate. Bravo!

okt 28, 2018, 5:19pm

Hey, stellar, long time is right. After the heart attack I've aged a lot, and quieted down too. I even read less, which annoys me no end. The meds make it difficult to concentrate.
I agree with everything you said. I expect new discoveries, especially about even earlier periods, to follow. Hopefully soon.
Another book, this time one I haven't seen, is "The war on ordinary people", by Andrew Yang. I think his diagnosis is right, jobs are drying up for ordinary people; but his cure is wrong. Universal Basic Income eventually must lead to slavery.
I shouldn't however, review books I haven't read. I expect to pick this up soon.

okt 29, 2018, 1:42am

>19 pomonomo2003: Joe, somehow I didn’t know about your medical travails. So sorry to hear this! In addition to wishing you good health and recuperation, I do hope you will accommodate to the meds, restored to your usual state of excellent concentration!

nov 9, 2018, 1:44pm

I think this article from yesterday's New York Times pertains to this conversation . . .

Crossing From Asia, the First Americans Rushed Into the Unknown:
Three new genetic analyses lend detail, and mystery, to the migration of prehistoric humans throughout the Western Hemisphere.


nov 9, 2018, 9:59pm

>21 rocketjk: yes, that’s a good account, and I found this one especially clear: