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Roots of Human Family Tree Are Shallow
Posted: Tue Jul 04, 2006 12:23 pm
by Chuck A. Walla
"That means everybody on Earth descends from somebody who was around as recently as the reign of Tutankhamen,"
http://abcnews.go.com/Technology/wireStory?id=2142987
I just wonder how this could possibly refer to Native Americans.
Posted: Tue Jul 04, 2006 12:54 pm
by Minimalist
Is the answer "Jesus?"
Posted: Tue Jul 04, 2006 1:18 pm
by alrom
This is a clear example of small-world phenomenon. It's more related to statistics and maths than to archaeology but nevertheless it's very interesting stuff...
http://en.wikipedia.org/wiki/Small_world_phenomenon
http://en.wikipedia.org/wiki/Social_network
Posted: Tue Jul 04, 2006 1:44 pm
by Chuck A. Walla
Minimalist wrote:Is the answer "Jesus?"
I don't even know what the question to that was.
I was just wondering how they could say that "all" modern humans, including presumably native South Americans who have supposedly been isolated for at least ten thousand years, have a common ancestor less then five thousand years ago. I agree with "alrom" on this.
Posted: Tue Jul 04, 2006 1:51 pm
by Minimalist
Don't mind me, Chuck.
I was just speculating about the answer to every question given by one particular poster on the board.
Posted: Tue Jul 04, 2006 2:17 pm
by stan
I think there is a flaw in this study because of the existence of
the "races," which have been separated for a long time.
Chuck has a good point, too.
If we were all so closely related, we'd look more alike.
Posted: Tue Jul 04, 2006 2:46 pm
by alrom
stan wrote:I think there is a flaw in this study because of the existence of
the "races," which have been separated for a long time.
Chuck has a good point, too.
If we were all so closely related, we'd look more alike.
If we assume that there's a new generation every 20 years, and that since the first europeans arrived at america (we won't get into the vindland stuff, let's just say that Columbus was the first one) 500 years have passed.
That means 25 generations. The number of 25th generation ancestors is 2 to the 25th power, which gives 33,554,432 ancestors. There is a significant probability that one of those millions of ancestors that every native south american has, was of european origin, a spanish conquistador who just scored with a mayan girl or something
This means that this hypothetical south american guy has european ancestors, but his blood is still probably 99,999999999% native.
Of course this is a rough estimate, as we all know people tend to mate with people close to them i.e. from their own town, and that isolated tribes don't mingle with others etc. I'm sure that those native tribes that live in remote islands in Indonesia are pushing this date thousands of years earlier than the date the article says. But they say that they took this into account.
Anyway, I'm sure that there are very isolated people with a high degree of inbreeding that push this date further
Posted: Tue Jul 04, 2006 2:56 pm
by Minimalist
As you said, alrom, this is a mathematical model and has nothing to do with genetics.
Posted: Wed Jul 05, 2006 1:10 am
by ReneDescartes
The article of ABC was in my opinion very bad science .We allready know that the human species narrowest genetic diversity occured about 75.000 years ago when humanity came very close to exctintion probably as the result of the eruption of Mt Tuba .Theanalysis of mitochondrial DNA shows only a few thousands of humans survived this cataclysmic event .We also know the human species was introduced down under at least 45.000 years ago.In fact hundersof arguments point against this article .
Clearly the standards of journalism at ABC network are below a level even acceptable in Kindergarten Another article produced by this network even stated the possible discovery of the Arch of Noah in Iran in a way that even gave credit to the possibility .
The article about thesocalled common ancestor of man 6000 years ago containsso many flaws it is impossible that is was not geared to reach its conclusion even before it was written .I canonly assume the supercomputer that was alledgetely used consisted of nothing more than 5 fingers and a copy of the bible
Posted: Wed Jul 05, 2006 1:50 am
by alrom
ReneDescartes wrote:The article of ABC was in my opinion very bad science .We allready know that the human species narrowest genetic diversity occured about 75.000 years ago when humanity came very close to exctintion probably as the result of the eruption of Mt Tuba .Theanalysis of mitochondrial DNA shows only a few thousands of humans survived this cataclysmic event .We also know the human species was introduced down under at least 45.000 years ago.In fact hundersof arguments point against this article .
Clearly the standards of journalism at ABC network are below a level even acceptable in Kindergarten Another article produced by this network even stated the possible discovery of the Arch of Noah in Iran in a way that even gave credit to the possibility .
The article about thesocalled common ancestor of man 6000 years ago containsso many flaws it is impossible that is was not geared to reach its conclusion even before it was written .I canonly assume the supercomputer that was alledgetely used consisted of nothing more than 5 fingers and a copy of the bible
Well, again, don't take this article as a study on genetic diversity. It's about ancestors, which is quite a different subject.
In fact, the authors of the article (not the guys at ABC News, I mean the ones who did the research) are stating an obvious thing: that we have a huge number of ancestors and so we all probably share some of them.
The original Nature article by Rohde, Olson & Chang (you must have a license to access it)
http://www.nature.com/cgi-taf/DynaPage. ... ml#letters
An article by Rohde about this subject:
http://tedlab.mit.edu/~dr/Papers/Rohde-MRCA-two.pdf
Posted: Wed Jul 05, 2006 2:19 am
by Guest
I was just speculating about the answer to every question given by one particular poster on the board
don't mind me, i find the article interesting but i thnk more studies need to be read before i propose an answer. though i am tempted to refute descarte and his off hand dismissal without looking at all the facts. not very objective or scientific.
have a common ancestor less then five thousand years ago
thoughthis is a possibility, i think the probabilities are faint.
Arch of Noah
its 'ark' not 'arch' if you are going to be biased at least spell it right. i think you have dismissed both articles out of poor science as your prejudice shines through. it doesn't meet your definition of science so it must be false and poor. that is bad science in and of itself.
The article about thesocalled common ancestor of man 6000 years ago containsso many flaws it is impossible that is was not geared to reach its conclusion even before it was written
if i remember correctly, this study was done to refute the bible and done by a non-religious person so what conclusion would he be trying to manipulate?
one can see how prejudice you really are as your contempt for the Bible is not well hidden and colors your opinions which means you are not objective in your studies thus you do poor science because you cannot remain objective.
objectivity means you have no pre-drawn conclusions but it is obvious you do especially when it comes to religious topics. you only accept a conclusion when it omits the Bible and that is not science but pushing a personal agenda.
science is very limited and will not provide all the answers andif you rely on science you won't get the answers till it is too late.
Posted: Wed Jul 05, 2006 6:12 am
by Frank Harrist
Spare us the sermon, most pious one.

Posted: Wed Jul 05, 2006 10:09 am
by Minimalist
your contempt for the Bible is not well hidden
It
deserves contempt.