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You would have to go back in time only 2,000 to 5,000 years — and probably on the low side of that range — to find somebody who could count every person alive today as a descendant.

Furthermore, Olson and his colleagues have found that if you go back a little farther — about 5,000 to 7,000 years ago — everybody living today has exactly the same set of ancestors. In other words, every person who was alive at that time is either an ancestor to all 6 billion people living today, or their line died out and they have no remaining descendants.

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I just thought it was neat.
 

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Posted by Tatiana (Member # 6776) on :
 
That is so cool! The last thing I heard along these lines came from the mitochondrial DNA studies they did years ago, that gave them a figure of 200,000 years ago for the last common ancestor for all of humanity. This is considerably closer! I wonder what the difference is?

It's really neat, though. We're cousins, Dag! Aren't you excited about that? :-P
 

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Posted by Joldo (Member # 6991) on :
 
Wait, this can't be! This means mine and Angelina Jolie's love can never be--it's incest.
 

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Posted by fugu13 (Member # 2859) on :
 
Mitochondrial DNA descends through the female line. Even were the common ancestor hypothesized by this simulation female, the line of descent would not for many (most) people be direct through a female line. There are many other ancestors, male and female, from the same generation as the possible common ancestor. Therefore mitochondrial DNA analysis cannot be used to discover the common ancestor projected here.

The 'mitochondrial eve' of humanity is from a bottleneck; this possible common ancestor occurs 'merely' because of the wonders of exponential growth and human migration.
 

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Posted by Amilia (Member # 8912) on :
 
So how likely is it that everyone who has traced their geneology back to Charlemagne (and hence to Adam) actually is decended from Charlemagne?
 

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Posted by Dagonee (Member # 5818) on :
 

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It's really neat, though. We're cousins, Dag! Aren't you excited about that? :-P

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So how likely is it that everyone who has traced their geneology back to Charlemagne (and hence to Adam) actually is decended from Charlemagne?

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According to the article, the more he traveled and slept around, the more likely it is.

The 5,000 to 7,000 year old thing is more interesting to me - going that far back, our ancestors are all the same.

When was Noah's Ark again?
 

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Posted by fugu13 (Member # 2859) on :
 
Charlemagne is well out of the range where we'd be descended from everybody, and is a particular person. He's not even in the right range to be the ancestor to everybody. This simulation only predicts that in a certain range there will be at least one common ancestor to every person, not that any particular person will be that common ancestor.

Now, anybody with any known european blood at all is almost certainly a very close cousin (on the scale we're talking) to charlemagne, but that's another matter.


Dagonee: the results of this simulation being accurate would make Noah's Ark not one whit more likely an occurrence ; the simulation relied only on approximately known details of population size and human migration. Its possible to get a similar result even if the population of the world were exactly the same as it is today; everyone from that time period would still all be our ancestors.
 

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Posted by Dagonee (Member # 5818) on :
 

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the results of this simulation being accurate would make Noah's Ark not one whit more likely an occurrence

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That's why it was funny, fugu.
 

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Posted by Bob_Scopatz (Member # 1227) on :
 
Mathematically, does it not also suggest that the most likely candidate(s) as the common ancestors of us all was a polygamist rapist who practiced incest?

People who had no children are right out. But the people who had the most children were/are going to be related to more and more of us down through the ages...

Genetically speaking, then, at least for humans, the long term best strategy for our "selfish genes" is/was to secure as many copulations as possible.

There are some startling implications of this when we sit down and try to draw a picture of our common ancestor.

Papa was a rollin' stone
Wherever he laid his hat was his home...

(of course, that next line doesn't apply...)
 

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Posted by Rakeesh (Member # 2001) on :
 
On another, "Hey, that's neat!" note, did anyone hear the report on NPR yesterday morning about the finding that ants can find their way back to their nests perfectly?

The experiments determined that it was through counting their footsteps. They did this by first shortening the legs of an ant, who when tryiong to get home then stopped short. Then they lengthened the legs-by gluing pighair prosthestics to make them longer-and the ant went further. They have no idea by what mechanism this is counted, though, since ants can wander for hours and still go home perfectly.
 

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Posted by KarlEd (Member # 571) on :
 

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Papa was a rollin' stone
Wherever he laid his hat was his home...

(of course, that next line doesn't apply...)

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Bob, you crack me up all the time, but now I'll never hear that song the same way again.
 

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