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Human populations are tightly interwoven
Nature ^ | September 29, 2004 | Michael Hopkin

Posted on 09/30/2004 11:17:34 AM PDT by AZLiberty

The most recent common ancestor of all humanity lived just a few thousand years ago, according to a computer model of our family tree. Researchers have calculated that the mystery person, from whom everyone alive today is directly descended, probably lived around 1,500 BC in eastern Asia.

Douglas Rohde of the Massachusetts Institute of Technology in Cambridge and his colleagues devised the computer program to simulate the migration and breeding of humans across the world. By estimating how different groups intermingle, the researchers built up a picture of how tightly the world's ancestral lines are linked.

The figure of 1,500 BC might sound surprisingly recent. But think how wide your own family tree would be if you extended it back that far. Lurking somewhere in your many hundreds of ancestors at that date is likely to be somebody who crops up in the corresponding family tree for anyone alive in 2004.

In fact, if it were not for the fact that oceans helped to keep populations apart, the human race would have mingled even more freely, the researchers argue. "The most recent common ancestor for a randomly mating population would have lived in the very recent past," they write in this week's Nature1.

Striking out

To work out how much different groups of humans mingled, Rohde's team simulated the rates at which a few pioneering people made journeys across the world to meet and breed with other populations. Their model gave each individual a certain probability of quitting their home town, country or continent and striking out for pastures new.

They were then able to name a time and place at which our most recent common ancestor lived. But who was this person? He or she must have had a flourishing family, says Rohde. "Maybe it was someone who happened to have 40 children or some such astronomical number," he says. "But it could equally have been someone with above-average productivity for a few generations." Instead of two kids, Rohde suggests, maybe the person and his or her direct descendants had three.

The fact that the person probably lived in Asia is down to its prime position along the most commonly used migration routes, Rohde suggests. "East Asia is at a crossroads," he says. "It's close to the Bering Strait and the Pacific."

No isolation

Rohde's simulation aims to include everyone alive today, and therefore relies on the assumption that no population has remained completely isolated for any significant length of time. Rohde is confident that this is the case; even Tasmania, once thought to be isolated by choppy seas, contains no people with purely Tasmanian blood.

If we discount those living in the world's remotest places, the common ancestor becomes more recent still, says Mark Humphrys, who studies human family trees at Dublin City University in Ireland. "Looking at the whole sweep of the Americas, Europe, Asia, right across to Japan, I wouldn't be surprised if we had a common ancestor in the AD years," he says.

A single prolific parent can have a vast influence once their descendants begin to multiply, Humphrys says. "The entire Western world is descended from Charlemagne, for example," he says. "There's really no doubt."

All or nothing

Besides dating our most recent common ancestor, Rohde's team also calculates that in 5,400 BC everyone alive was either an ancestor of all of humanity, or of nobody alive today. The researchers call this the 'identical ancestors' point: the time before which all the family trees of people today are composed of exactly the same individuals.

This recent date is not really surprising either, Rohde says. Anyone whose lineage survived for a few generations was likely to have descendants spread all over the world. At the identical ancestors point, then, our ancestors came from every corner of the globe, although those from far afield are unlikely to have made a significant contribution to our genetic make-up.

Nonetheless, the results show that we are one big family, Rohde says. As he and his colleagues write: "No matter the languages we speak or the colour of our skin, we share ancestors with those who planted rice on the banks of the Yangtze, who first domesticated horses on the steppes of the Ukraine, who hunted giant sloths in the forests of North and South America, and who laboured to build the Great Pyramid of Khufu."


TOPICS: Science
KEYWORDS: archaeology; commonancestor; computermodeling; dna; ggg; godsgravesglyphs; helixmakemineadouble; history; mtdna
Seems unlikely to me, especially with migrations that occurred over 10,000 years ago. The author has argued that no one living today is a pure descendant of one those migrations.
1 posted on 09/30/2004 11:17:35 AM PDT by AZLiberty
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To: AZLiberty
re: Rohde's team also calculates that in 5,400 BC everyone alive was either an ancestor of all of humanity, or of nobody alive today.)))

Kerry's speechwriter?

2 posted on 09/30/2004 11:20:27 AM PDT by Mamzelle (Pajamamama)
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To: AZLiberty

My ex girlfriend was my cousin? Freaky!

;)


3 posted on 09/30/2004 11:22:20 AM PDT by Crazieman (Hanoi John Effin Kerry. War Criminal. Traitor. Democrat.)
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To: AZLiberty
Human populations are tightly interwoven

Occasionally yes, or else no human population ...

4 posted on 09/30/2004 4:19:43 PM PDT by fnord (Being humble doesn't mean thinking less of yourself. It means thinking more of others.)
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To: AZLiberty

These computer simulations are even less reputable than mtDNA "studies". It's amazing how thin an ancestry can become. My best friend has no first cousins. He's an only child. His mother was an only child. Her father was orphaned at a young age, losing his parents and only sibling (sister) to an accident, so she had no first cousins.

For that matter... my family has lived on the same farm since 1851, and was in town (although calling it a town at that point was dubious) for about seven years before that. While doing some rudimentary genealogical research, I found another family has lived in the same town for most of that time, and prior to that, in similar proximity to my family, going back hundreds of years in America -- without ever intermarrying (apparently -- I wasn't meticulous).

GIGO. :')


5 posted on 09/30/2004 11:08:02 PM PDT by SunkenCiv ("All I have seen teaches me trust the Creator for all I have not seen." -- Emerson)
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To: blam; FairOpinion; Ernest_at_the_Beach; SunkenCiv; 24Karet; 2Jedismom; 4ConservativeJustices; ...
Please FREEPMAIL me if you want on, off, or alter the "Gods, Graves, Glyphs" PING list --
Archaeology/Anthropology/Ancient Cultures/Artifacts/Antiquities, etc.
The GGG Digest
-- Gods, Graves, Glyphs (alpha order)

6 posted on 09/30/2004 11:57:29 PM PDT by SunkenCiv ("All I have seen teaches me trust the Creator for all I have not seen." -- Emerson)
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To: AZLiberty
Seems to me that this computer model's conclusions would be hard to prove..

First, it's a "simulation"..
Second, it's a "probability model"..

If we were talking Global Warming, we would dismiss it out of hand..

7 posted on 10/01/2004 3:49:44 AM PDT by Drammach (Freedom; not just a job, it's an adventure..)
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To: Drammach
First, it's a "simulation"..
Second, it's a "probability model"..

As a civil engineer I can guarantee that every time you walk into a building you're staking your life on both. 

The math isn't too hard to follow.  We all had two parents, four grand parents, eight-- well, you get the picture.   Pat Paulsen said this proves the world population is obviously shrinking, but I think it shows that the world's common ancestry could be as recent as about 30 generations, or 600 years. 

Hopkin took this idea a step further and plugged in how much people travel and showed that our common grandpa shouldn't be farther back than 3500 years. 

It's "probably" true.

8 posted on 10/01/2004 4:37:14 AM PDT by expat_panama
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To: expat_panama

It's probably not true, since there are scads of assumptions in any such a simulation, most of which are probably either untested or untestable. Is it really reasonable to expect that every member of an isolated tribe in the mountains of New Guinea, that had never even seen Europeans (much less intermarried with them) before 1950, shares a recent common ancestor with a family in Iceland that has a complete geneology going back to 800 AD? Not hardly.


9 posted on 10/01/2004 7:22:21 AM PDT by Keith Pickering
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To: AZLiberty
Besides dating our most recent common ancestor, Rohde's team also calculates that in 5,400 BC everyone alive was either an ancestor of all of humanity, or of nobody alive today.

I realize that this study is hoakum but this date falls amazingly close to the date of Adam according to some biblical timelines.

10 posted on 10/01/2004 8:19:42 AM PDT by John O (God Save America (Please))
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To: Keith Pickering
If we're talking belief systems (i.e. the New Guinea and the Lakota were created separately) then we need to study the Holy Writings.  

If we're talking about physical movement and mathematical probabilities, then we're discussing whether or not the various populations (such as those in New Guinea) were hermetically sealed or was there any movement at all in the last three and a half millinea.

The world population back then was less than 100 million.  For you or I to not be descended from cousins there would have had to have been a population of 4,789,048,565,205,902,682,369,834,459,844,000,000, 000,000,000,000,000,000,000.   So we both agree that

    1.   We don't know anything for sure

    2.    People intermarried a lot

    3.    People moved around a lot.

We could go at this strictly from Sacred Texts also but (please forgive) I'm not sure where you're coming from.

11 posted on 10/01/2004 8:35:15 AM PDT by expat_panama
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To: Professional Engineer

Noah ping


12 posted on 10/01/2004 8:46:38 AM PDT by msdrby (remind me to drink more water)
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To: Keith Pickering
Is it really reasonable to expect that every member of an isolated tribe in the mountains of New Guinea, that had never even seen Europeans (much less intermarried with them) before 1950, shares a recent common ancestor with a family in Iceland that has a complete geneology going back to 800 AD?

Depends on how you define "recent".

13 posted on 10/01/2004 9:28:26 AM PDT by A.J.Armitage (http://calvinist-libertarians.blogspot.com/)
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To: SunkenCiv; Fedora; JimSEA
There's an Indian Anthropologist/Archaeologist named Narain who is quoted by Victor Mair (The Tarim Mummies) who thinks all people of European descent originated in the Gansun(sp) region of present day China. That's where the red-headed mummies were discovered too.
14 posted on 10/01/2004 11:16:40 AM PDT by blam
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To: expat_panama
If we're talking belief systems (i.e. the New Guinea and the Lakota were created separately) then we need to study the Holy Writings... We could go at this strictly from Sacred Texts also but (please forgive) I'm not sure where you're coming from.
Keith was talking about genealogies, not Holy Writings or Sacred Texts. Since the authors of the study claim that everyone is descended from a single individual 3500 years ago, and humans have been in the Americas for at least 10,000 years (presumably having ancestry outside the Americas, although Native Americans generally believe their ancestors have always been here), there's obviously very little chance of these study results' being plausible.
If we're talking about physical movement and mathematical probabilities, then we're discussing whether or not the various populations (such as those in New Guinea) were hermetically sealed or was there any movement at all in the last three and a half millinea.
Mathematical probabilities don't enter into it -- someone in Eurasia 3500 years ago couldn't be the ancestor of every Native American, even though (in my view) the oceans have been traveled by a huge variety of different cultures for tens (maybe hundreds) of thousands of years.

Even genetic studies don't / can't tell us about geographical origins, except in very short and recent time frames. The population in the earliest known agricultural, riverine societies rose quite quickly. The civilizations in those societies had larger families (more children who survived), and could support non-food gathering activities on a large scale. Those activities included the invention of recordkeeping and writing systems, accounting, art, centralized grandiose cults, cities, and standing armies.

Generally speaking, the parents wound up with many more descendants than parents in hunter-gatherer societies. This is a sort of discontinuity that seems to be ignored (or not thought about) in all the mtDNA studies which show greater genetic diversity in Africa. That genetic diversity has to do with the type of food-gathering that has gone on in Africa, rather than an exclusionary antiquity for that continent. FTM, since mitochondria have sex, mtDNA studies don't hold water except in very short, recent time frames (like, who is buried in Jesse James' purported grave).
The world population back then was less than 100 million. For you or I to not be descended from cousins there would have had to have been a population of 4,789,048,565,205,902,682,369,834,459,844,000,000,000,000,000,000,000,000,000. So we both agree that.
I know my family lines back (in some cases) ten or twelve generations. I've never found ANY overlapping lines. While it's true that my family seems a little unusual (my grandfather was born in 1875; his grown brother died in 1873; their father was born in 1825; one of our female ancestors from the first American generation died aged at least 100), family lines are unique, sometimes even among siblings. So, yeah, We don't know anything for sure, People intermarried a lot, and People moved around a lot.

The bozos who made this study assumed that all lines converge, and that the point at which they converge could be discerned. They erred.
George W. Bush will be reelected by a margin of at least ten per cent

15 posted on 10/01/2004 11:56:36 AM PDT by SunkenCiv ("All I have seen teaches me trust the Creator for all I have not seen." -- Emerson)
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To: SunkenCiv
 -- someone in Eurasia 3500 years ago couldn't be the ancestor of every Native American...

The point Hopkin is highlighting is that since (as we agree) that it's easy to believe that from say, 1500BC to 500BC that at least one guy visited the Americas from Asia, and shared genes.  We don't have photos but it's simply not reasonable to say it didn't happen.

Since then, 2,500 / 20 = 125 generations have passed.   Remember that this is 125 doublings -- a factor of some 40 digit number.  This would spread the guy's genes to every single human in the Americas.  This isn't hard to believe considering that it took about that long for the first Eurasians to cover that area.   The only way that his family tree would not have spread would be that maybe the guy had some kind of genetic condition where everyone in his family dies at birth (rim shot), or maybe him and the little woman moved to the moon (cow bell).

But seriously folks, not to worry-- I promise not to take advantage of our newly discovered family ties in order to borrow money.

16 posted on 10/01/2004 1:09:13 PM PDT by expat_panama
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To: Keith Pickering

Well said.


17 posted on 10/01/2004 1:23:22 PM PDT by SunkenCiv ("All I have seen teaches me trust the Creator for all I have not seen." -- Emerson)
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To: Searching4Justice
"No matter the languages we speak or the colour of our skin, we share ancestors"

Uh oh....don't let the Arabs know when they shake hands with a Jew ....it could be their cousin! :o

18 posted on 10/01/2004 1:32:03 PM PDT by BossLady (Member of the Pajama Jihad Conspiracy.......)
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To: expat_panama; blam
Not reasonable to not believe it? Uh, no. It's not only reasonable to not believe it, but what these two authors are saying is simply not possible. As in impossible. And I'm not an isolationist, not at all. They're saying that everyone in Africa -- everyone -- and everyone in the Amazon rain forest, no matter how isolated -- everyone -- has a common ancestor who lived in Asia 3500 years ago.

Ancestral lines can be quite narrow. With (usually) 46 chromosomes, once our great-great-great-great-grandparents are considered -- 64 people -- only 46 of them (at most) have contributed anything to our makeup. With our (usually) 23 pairs, a mating pair of humans can produce 2 ^ 23 possible combinations, in theory not in practice. Isolated populations can be remain viable, with a quite narrow ancestry on a genealogy chart. And I'm a multiregionalism advocate.

The study isn't scientific because it isn't based on actual evidence of any kind, nor is it falsifiable because there's nothing to falsify. Within the past couple of days a post-Olympics study of sorts was quoted on FR, which claimed that in 150 years, women will have faster sprint times than men, based on the curve of improvement in finish times. That doesn't take into account physiological differences (it also played fast and loose with the data). This "study" is no more reliable.
George W. Bush will be reelected by a margin of at least ten per cent

19 posted on 10/01/2004 1:34:49 PM PDT by SunkenCiv ("All I have seen teaches me trust the Creator for all I have not seen." -- Emerson)
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To: BossLady
wait till they find out we are all the same guy !!! major QQQQQQQQQQoooooooppppsssss
20 posted on 10/01/2004 5:36:56 PM PDT by Searching4Justice
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To: expat_panama

it's easy to believe that from say, 1500BC to 500BC that at least one guy visited the Americas from Asia, and shared genes. We don't have photos but it's simply not reasonable to say it didn't happen.

Since then, 2,500 / 20 = 125 generations have passed. Remember that this is 125 doublings -- a factor of some 40 digit number. This would spread the guy's genes to every single human in the Americas.

Not at all necesarily true. Among my family, in my generation, two out of three siblings have no children. In my parent's generation, (father's side) one out of two have no children; mother's side, also one out of two have no children. So right now, my four grandparents have a combined total of ONE great-grandchild between them (and probably won't have any more, either.) That's three generations removed. If that kid becomes a priest, or dies young, all four grandparents will be out of the descendents game entirely.

This kind of thing happens a lot, especially in societies with high infant mortality. Which means most of the human race throughout most of its history.

21 posted on 10/02/2004 10:08:48 PM PDT by Keith Pickering
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To: Keith Pickering
Another way to think about this is that for all species -- including humans -- their ecological niche has what economists call a "carrying capacity", i.e., the highest population that the food supply will support. When a population reaches its carrying capacity, it will stabilize at or just below it, with only minor fluctuations.

Living in an age of population explosion, it's hard to recall that for most of human history, the population was fairly stable. This means that populations were not doubling every generation, they were about the same every generation. In other words the average couple produced and average of two descendants. For every couple that produced four (and this was a sizable fraction of the population) there was another couple that produced none (also a sizable fraction of the population).

Unless a newcoming interloper's genes are better fit (in Darwinian terms) than those of the native population, there is simply no way to be sure that his descendents (if any) will not die out in a few generations or less.

22 posted on 10/02/2004 10:21:20 PM PDT by Keith Pickering
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To: Keith Pickering
Another way to think about this is that for all species -- including humans -- their ecological niche has what economists call a "carrying capacity", i.e., the highest population that the food supply will support. When a population reaches its carrying capacity, it will stabilize at or just below it, with only minor fluctuations.

Living in an age of population explosion, it's hard to recall that for most of human history, the population was fairly stable. This means that populations were not doubling every generation, they were about the same every generation. In other words the average couple produced and average of two descendants. For every couple that produced four (and this was a sizable fraction of the population) there was another couple that produced none (also a sizable fraction of the population).

Unless a newcoming interloper's genes are better fit (in Darwinian terms) than those of the native population, there is simply no way to be sure that his descendents (if any) will not die out in a few generations or less.

23 posted on 10/02/2004 10:26:56 PM PDT by Keith Pickering
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To: BossLady
when they shake hands with a Jew ....it could be their cousin!

You've nailed it.  All over the world people have this congenital believe about 'blood and soil'-- that 'this land is for our people and not for inferior people'.  They'll say that anyone who suggest that our ancestry does not extend back to the Beginning is not normal.

They're right-- I used the word "congenital" because I think these beliefs are actually hard wired into us at birth.  Overcoming these prejudices may be a big step toward reality, but it's just not normal.  The irony is the very fact that this common belief is so universal is even more proof of recent ancestry.

24 posted on 10/03/2004 7:54:39 AM PDT by expat_panama
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To: Crazieman

well, most of us ARE cousins to everyone else -- the degree of relationship will vary (100th cousin anyone!?)


25 posted on 10/03/2004 12:11:13 PM PDT by Cronos (W2K4)
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To: Keith Pickering

WEll, that is an extreme example -- however, most of the peoples populating the Eurasian continent and Africa north of the Sahara have had regular contacts for millenia. The more apparent are the Caucasians -- you can most definitely say that if you have any amount of Caucasian blood, you are related to those who faced CAesar's troops in 54 B.C. and those who created the VEdas in the second millenia and those who built the pyramids and those who trudged with Moses.


26 posted on 10/03/2004 12:14:11 PM PDT by Cronos (W2K4)
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To: Keith Pickering

There are extremes such as the MElanesian tribes in Papua New Guinea (Australoids I think and related to the Australian Aborigines) or a remote South American tribe or the Bushmen. Most other groups are not that isolated


27 posted on 10/03/2004 12:15:30 PM PDT by Cronos (W2K4)
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To: BossLady
Uh oh....don't let the Arabs know when they shake hands with a Jew ....it could be their cousin! :o

They already know they are cousins -- they are both of the SEmitic race (as opposed to Europeans, Iranis, Indians who are Aryans) and, biblically, both are descended from Abraham so are cousins....
28 posted on 10/03/2004 12:17:24 PM PDT by Cronos (W2K4)
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To: Keith Pickering

#21, #22, well put (again).


29 posted on 11/26/2004 8:28:06 PM PST by SunkenCiv ("All I have seen teaches me trust the Creator for all I have not seen." -- Emerson)
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To: AZLiberty

bttt, and a related topic:

Maori Men And Women From Different Homelands
ABC Science News ^ | 3-27-2003 | Adele Whyte
Posted on 09/06/2004 5:15:41 PM PDT by blam
http://www.freerepublic.com/focus/f-news/1208808/posts


30 posted on 11/26/2004 8:29:23 PM PST by SunkenCiv ("All I have seen teaches me trust the Creator for all I have not seen." -- Emerson)
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February 2005 bump
31 posted on 02/04/2005 11:24:35 PM PST by SunkenCiv (Ted "Kids, I Sunk the Honey" Kennedy is just a drunk who's never held a job (or had to).)
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Just updating the GGG information, not sending a general distribution.

To all -- please ping me to other topics which are appropriate for the GGG list. Thanks.
Please FREEPMAIL me if you want on or off the
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32 posted on 07/02/2006 5:58:44 PM PDT by SunkenCiv (updated my FR profile on Wednesday, June 21, 2006.)
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· join list or digest · view topics · view or post blog · bookmark · post a topic ·

 
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Just updating the GGG info, not sending a general distribution.

To all -- please ping me to other topics which are appropriate for the GGG list.
GGG managers are Blam, StayAt HomeMother, and Ernest_at_the_Beach
 

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33 posted on 02/23/2008 4:03:22 PM PST by SunkenCiv (https://secure.freerepublic.com/donate/___________________Profile updated Tuesday, February 19, 2008)
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