Steve Olson in Why We're All Jesus' Children has a gimmicky exposition on the reticulated character of our genealogies. But Olson tries to pull a fast one here:
It gets even stranger. Say you go back 120 generations, to about the year 1000 B.C. According to the results presented in our Nature paper, your ancestors then included everyone in the world who has descendants living today. And if you compared a list of your ancestors with a list of anyone else's ancestors, the names on the two lists would be identical.
The reality is that quantity, not quality, counts, you need to know how many times someone was your ancestor, not that they were your ancestor. More here.
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I posted on a different thread, but I'll repeat here.
I just can't believe the 1200 BC date. It seems that the guy must have been doing statistical modelling on a geography-free world-size population.
Take, for example an Araucanian Indian (southern Argentina), an African aborigine, a New Guinea highlander, and perhaps a !kung from S. Africa. The New Guinea highlander and the !kung are part of the general Eurasian gene pool, but even with them I can't be intutitively confident that they shared ancestors with, say, a Norwegian or an Inuit. The other two cases are much more difficult.
And as I said, this statistic becomes more true as time goes on and certain poeoples disappear. I don't know if there are any Araucanians left today, pureblood or otherwise, so from a scientific point of view I'd set the end clock at 1500 AD and ask whether setting the beginning date back to 1500 BC would salvage the theory.
If someone were to say 95% of the people today, or even 99%, it would still be a meaningful hypothesis and would seem much more plausible. But the number I always see is 100%.
If someone were to say 95% of the people today, or even 99%, it would still be a meaningful hypothesis and would seem much more plausible. But the number I always see is 100%.
this is fair IMO.
What happened to the *Y-Chromosomal Adam* hypothesis, where this was assumed to be the most recent common ancestor to all extant Y haplogroups, if i'm correct. Y-Chromosomal Adam was theorized to have lived somewhere between 65,000-90,000kya.
Also, would it or would it not be correct to assume that we all(even the low IQ) descend from paleolithic high-IQ individuals(high IQ for their era). The genes of our most bright ancestors eventually 'trickled down' to everyone until there was a species wide increase in brain size & general intellectual capacity. Isn't this how humanity evolved? We didn't get human "by accident", did we? It would seem that there should have been a selection for intelligence which led those of higher ability to have much better mating success.
Hmmm, I wonder where today's chimps & gorillas will be three million years from today, if their respective evolutionary strategies remain static for that time period?
Do genes, barring mutation, stay the same when strategy remains the same?
I meant "Australian aborigine", of course.
What happened to the *Y-Chromosomal Adam* hypothesis, where this was assumed to be the most recent common ancestor to all extant Y haplogroups, if i'm correct. Y-Chromosomal Adam was theorized to have lived somewhere between 65,000-90,000kya.
it is still around, and seems valid.
Do genes, barring mutation, stay the same when strategy remains the same?
some genes can be functionally constrained (selection against changes) and remain as they are for hundreds of millions of years. but most genes will substitute from one allele to another if neutral fitness effects can be managed (either loss of function is irrelevant, or an alternative form arises which performs the same function equally well).