What’s the current dope on this from any anthropology experts here?
(And for any who aren’t, please don’t bother to quote the drivel from Wikipedia unless you read the source article from Chang. As nearly as I can tell, whoever wrote the Wiiki piece had no idea of the difference between mathematical modeling and actual currently accepted historic human migration patterns.)
Well, I know who my daddy and mommy were, even if you don’t know yours.
I suppose your real question is meant to be something about human evolution, but I can’t make head nor tail of what it is about human evolution that you are trying to ask. Perhaps you could reword your question so as to be, you know, coherent? A link to the Wikipedia piece that you are dissatisfied with might give us a clue too.
I expect it’s this one, or one of the related ones quoting the same paper:
I’m related to Megan Smolenyak-Smolenyak ------ I have heard more about this than I care to. Don’t get me wrong; I find it fascinating ------- but at a certain poijnt it becomes Ecedrin Headache #273
Current thought is Adam is 142,000 or so years back and Eve at maybe 150,000 years back or more. I know you don’t like Wiki but
covers it pretty fairly.
I’m my own Grandpa.
Accident with a contraceptive and a time machine?
Well, I’m not taking any time travel advice from you.
You can claim that, but I suspect you’ll be crawling to him when the Brainspawn attack.
We don’t have any way of knowing this other than using modeling. We may, at some future date, have the technology to analyze everyone’s DNA (or a sufficiently large sample) and project backwards, but my understanding is that we have difficulty projecting back more than a few generations right now.
And I don’t see that the modeling results in the wikipedia article are inconsistent with what we know about human migration patterns. We’ve had a half-dozen threads on this subject over the years, so you might want to search them and see what was discussed.
That’s covered in the article I linked to earlier:
What the OP desires, I think, is a date for the last identical ancestor, which could be identical to the patrilineal, but probably isn’t, the patrilineal (and matrilineal) ancestor just has the benefit of having passed down a packet of genes that makes it possible to trace him.
I’m not an anthropologist, but it seems to me as well that the 15,000 to 5,000 year estimate is a fairly uninteresting mathematical exercise with insufficient anthropological input. Don’t we have to go back to at least before the ancestors of the Aboriginal Australians arrived in Australia?
New Scientist recently had a cover article (Our true dawn: Pinning down human origins, 26 November 2012 by Catherine Brahic; only available to subscribers) about recent research that showed that humans average fewer mutations in the DNA per generation than previously thought. Therefore, divergences in the past took place longer ago geneticists believed.
That would give a ballpark, depending on what the OP is asking for.
No, we don’t. It’s unlikely that any surviving Australian does not have at least one non-Australian ancestor, even if he doesn’t know it. Before the so-called Age of Discovery, things might have been different. But that was 500 years ago and there’s been a lot of hanky-panky going on in the ensuing years!
The OP is looking for actual genetic data for the identical ancestor. Such data simply doesn’t exist, and is not likely to exist for some time to come, if ever.
I’ll ask my evolutionary Anthro teacher and get back to you.
Let me clarify a couple of things.
The “last identical ancestors point” is an actual concept, not a term I invented. While it’s similar to the most recent common ancestor, it’s more specific.
Mathematical modeling such as done by Chang (and referenced several places in Wikipedia) yields a nonsensical result of “5-15K years.” This is beyond stupid. It’s impossible. We start out in Africa 200K years ago, and move out (the population that moved out for good) about 75K years ago. Svante Paabo thinks one tiny portion of the population that moved out and ended up being Out of Africa Eve to the Eurasian population interbred with Neanderthals. Neanderthal ancestors in turn Africa quite a bit earlier.
If we ignore the Neanderthal part of the Eurasian gene pool, our last identical ancestors point would be somewhere over 75K years ago, but perhaps quite a bit longer depending on the time of separation of the sub saharan populations who stayed in Africa. If we accept the Neanderthal interbreeding theory, then would not the identical ancestors point get pushed back over 500,000 years for the identical ancestors point for Eurasians (Neanderthal-mix sub-portion of human populations) versus sub-saharans?
This is the thing I’m trying to get at. There is such a stark contrast between a mathematical modeling that assumes “random mating” and gets a number of 5-15K years, and an analysis of historic migration patterns that establishes a minimum of 100K plus years for the last human identical ancestors point–with an upper bound of 500K+ years.
The various undereducated replies listed above are not helpful. They are, in my view, a reflection of a distressing trend back toward a simplistic creationist history of mankind but have little in common with fact. I’m wondering if anyone on the board wants to advance fact.
Exapno is closer to the kind of reply I find helpful.
ETA: My comment about Wikipedia was simply to let posters know I’m not interested in hearing a parroting of bad information. If you have some insight on the topic, I’d like to hear it. If not, I don’t need to be told to read Wikipedia.
This is from my professor:
The claim in Wikipedia actually comes from a pdf paper by Douglas Rohde, a well-credentialed PhD, who, I think, bases his claims on somewhat elaborate simulations using real-world topology.
The claim implies that the identical ancestors of aboriginal Australians all had descendacy paths which migrated away from Australia after 13,000 BC to become ancestral to all living humans. This may strike us intuitively as unlikely, but it seems to be the result found by Rohde.
The claim depends on parameters, e.g. the leakage from Australia (prehistoric people who accidentally rafted away to New Guinea), which is explicitly shown on page 14 of the paper. Rohde discusses some inter-continental migrations, but I see no mention of Australia and have no idea how he guesstimated that parameter. Small changes in the parameters can have a big effect on results like Identical Ancestor Point. The real numbers may be unknowable and likely to be more conservative than those found with the model – I suspect Rohde would agree with that.
I don’t understand how this:
. . . follows from this:
Just because humans moved out of Africa doesn’t mean that a wall of separation came down around the continent. There was always leakage across the Sinai and around the coasts.
Granted, for most of human history people who lived in China weren’t mating with people who lived in South Africa. But Chinese mated with central Asians who mated with Arabians who mated with north Africans who mated with central Africans who mated with south Africans. Over hundreds of generations a Chinese could easily become ancestral to an African, or even to every African. Or the reverse.
I know what it is, and it was linked to early in this thread.
No, it’s not. I believe this work was done before the Neanderthal genetic data was known, and if we do ignore it, there is no reason that the identical ancestor point has to be > 75k years ago. Where are you getting that from?
Your professor needs to do a little more research.