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Re: Peopling of Americas
Posted: Mon Feb 25, 2008 9:52 pm
by john
Roxanne wrote:Just playing devil's advocate here. If, and I don't doubt there were other incursions from other populations groups other than the Siberian route, but if there were significant earlier cultures from Europe or Polynesia or even a different location in Asia than Siberia, where is the DNA evidence?
There doesn't seem to be any European Y's or strictly polynesian mtdna floating around in the Native American populations. Did the original settling colonies fail and all die without leaving any offspring or refuse to interbreed with the new siberian interlopers? Were the numbers so small in light of the later influx from Siberia, that their dna was completely swamped and diluted to the point it doesn't form a whisper in the current native populations? It seems the Native American dna samples are asian with some minor twists from isolation. Why can't we find a single norse signature in the native populations of the east coast? Why aren't we finding dna signatures common in Tonga in Peru?
Not trying to pick a fight just looking for alternative theories as to the lack of lingering DNA signals. Roxanne
Roxanne -
http://www.madsci.org/posts/archives/20 ... .Ge.r.html
Remember that - as far as I know - we have no skeletal remains prior to maybe 10.5kbp to test. Thus, using tests of the Beringian/Amerind population as an indicator for far earlier migration is a contradiction in terms.
The existence of xxx kbp MTDNA in Siberia or Europe does not establish ANY proveable date of latter migration without actual, physical remains.
All you have is a gap in time in which the bearers of that DNA line could have lived anywhere.
Second. It is my understanding that the MTDNA signature disappears if the mother-line dies out.
This complicates matters.
Lines of very early people who populated the Americas could, and probably did, die out in a relatively short period of time. The MTDNA line would have been lost. Without physical remains, they are simply off the radar.
john
Posted: Wed Apr 02, 2008 7:03 pm
by MichelleH
Here is some more on this topic: (pre-Clovis!)
Fossilized feces found in Oregon suggest earliest human presence in North America
http://seattletimes.nwsource.com/html/l ... op03m.html
More will be available tomorrow after the press embargo lifts on the original paper from the University of Oregon.
Watch the news page on the website for the update.
Posted: Wed Apr 02, 2008 7:54 pm
by Minimalist
No shit, boss?
Posted: Wed Apr 02, 2008 8:08 pm
by MichelleH
No shit dude.....cool, eh?
Posted: Wed Apr 02, 2008 9:28 pm
by Rokcet Scientist
A measly 1,000 years pre-Clovis...?
Posted: Wed Apr 02, 2008 9:56 pm
by dannan14
Baby steps to the door.....
baby steps to the light of day.....
Feces
Posted: Thu Apr 03, 2008 9:11 am
by Cognito
Michelle, your link was dead so I went somewhere else for the story:
http://www.sciencedaily.com/releases/20 ... 141109.htm
From the article:
"The Paisley Caves are located in the Summer Lake basin near Paisley, about 220 miles southeast of Eugene on the eastern side of the Cascade Range." That ain't anywhere near the water, folks.
At 14,300 years ago (12,300bc) I wonder how many years it took that tribe to migrate from Asia to Oregon, and possibly move from a seagoing culture to hanging out in caves. I'm also assessing the odds of finding human feces in the first place (don't try this at home). It would be fair to state that these pre-Clovis people were in North America for hundreds if not thousands of years before taking their famous dumps.
We now have a new field of science:
Archaeoscatology.
And look at the shit eatin' grin on Dennis Jenkins' face in the picture. He knows he just killed off Clovis First -- one more time.
Posted: Thu Apr 03, 2008 10:28 am
by Digit
It has been estimated in the past Cog, don't ask me how, that HG groups migrated about 15 miles per generation. Makes sense that you would wish to maintain contact with friends and family.
Posted: Thu Apr 03, 2008 11:09 am
by kbs2244
But Digit,
That assumes walking.
The Polynesians kept up multi generational family ties over thousands of miles distance.
Posted: Thu Apr 03, 2008 11:26 am
by Digit
Agreed KB. The point I was making was that if they had indeed walked into America, and continued on foot, then without a doubt, assuming the 15 miles to be correct, the time taken to reach some of the southern sites infers, as Cog said, a time scale of hundreds or thousands of years.
The alternative has to be sea travel, one or other scenario has to be wrong.
Posted: Thu Apr 03, 2008 11:40 am
by Minimalist
that HG groups migrated about 15 miles per generation.
That's easy. They take the distance from Alaska to Tierra del Fuego and divide by the amount of time that the existing theory says they had to get there.
Of course, if the existing theory is wrong then all that goes out the window, doesn't it?
I'm having trouble figuring out WHY HG groups would move on voluntarily? Unless they depleted the resources in a given area there would be no reason for them to leave. Generally, we do not see small H/G groups having that sort of dire impact on the environment. For that to happen takes agriculture and a population boom.
But, of course, we don't have agriculture or a population boom in the New World.....do we?
Posted: Thu Apr 03, 2008 12:08 pm
by Digit
I think the clue is in the definition of 'generation' Min. A recent research project established to ascertain the ideal numbers of people to send on a trip to colonise another planet came up the the magical number if 15 couples.
This, they argued, provided sufficient variation in genetic make up and was small enough to prevent serious conflict.
It also happens to be the size of the suggested HG groups, and in one generation that number could easily double, placing strains on both community and resources, thereby promoting a move that was sufficient in distance to make the heart grow fonder but remain in contact.
Posted: Thu Apr 03, 2008 12:50 pm
by Minimalist
I wonder.
Between hunting casualties, infant/childbirth mortality, and predation it seems that population growth estimate seems a tad high. But, for the hell of it, let's assume that it works.
Which group leaves? They couldn't flip a coin....coins were invented until 700 BC. It seems like a recipe for conflict.
Posted: Thu Apr 03, 2008 1:08 pm
by Digit
Tradition might well play a part here Min, animals often kick the youngsters out of the home territory, and youngsters are often more adventurous than their elders.
Posted: Thu Apr 03, 2008 3:36 pm
by Sam Salmon
Fossilised lumps of excrement - coprolites - excavated from caves in Oregon. They contain "the oldest human DNA obtained from the Americas," according to Eske Willerslev, who led the analysis work confirming their identity.