A whole bunch of very interesting videos have been posted on youtube from this interesting symposium that took place this May. A few that caught my eye:
CARTA: The Origin of Us - Fossils of Modern Humans Interbreeding within and outside of Africa
CARTA: The Origin of Us -- Richard Ed Green: Interbreeding with Archaic Humans outside Africa
CARTA: The Origin of Us -- Christopher Ehret: Relationships of Ancient African Languages
CARTA: The Origin of Us -- Chris Stringer: Fossil Record of Anatomically Modern Humans
CARTA: The Origin of Us--Rick Potts: African Climate of the Last 400000 Years
CARTA: The Origin of Us -- Ofer Bar-Yosef: Evidence for the Spread of Modern Humans
CARTA: The Origin of Us -- Michael Hammer: Interbreeding with Archaic Humans in Africa
This should be very interesting watching. Feel free to leave a comment if you notice anything new or interesting in any of the videos.
Richard Ed Green has an interesting graph right at the end of his talk. The main purpose of it is to show the denisovan population diverging away from the main human group about a 2 million years ago.
ReplyDeleteInterestingly it does show a few other things IMO. Although the time scale is very hard to read, and what is a micro T anyway?
(1)All the human reference populations track together as if they were one breeding population until about 250kya when the Africans start to diverge away from each other and the out of Africa (OOA)group.
(2) The Dinka of the Nile/Sudan are the last of the african groups to split off from OOA group.
(3) The OOA group breeding population size tracks together for much longer than I expected. Karitiana/Papuan are the first to split off. ~20kya
(4) Han seem to diverge from French/Sardinian very late. Puzzling. Perhaps this a resolution issue. In which case the true split could be Han/Papuan/Karitiana at 35kya. Which makes slightly more sense.
(5)There appear to be three periods of population expansion.
a)250kya (origin of Homo Sapien skills?)
b)20-30kya. (Gravettian?)
c)~10kya. (Neolithic?)
(6)Han population expansions (GRavettian and Neolithic) seem to lag a bit behind FRench/Sardinian. Suggests that it happened first in near east and spread. I only mention it because of the recent work showing earlier and earlier dates for the chinese neolithic.
(7)Papuans have two population surges also roughly corresponding to lagged Gravettian and neolithic. The suggestion IMO is that ideas travelled rapidly to the Han and more slowly to the Papuans over the water.
(8)The Dinka and Yoruba seem to have a surge 50kya. Hard to know why. The Madenka (whoever the hell they are) also have a minor 35kya surge.
(9)None of the african groups seem to have benefitted from the neolithic. Surprisingly.
"The Madenka (whoever the hell they are)"
ReplyDeleteA West African language group. Used to be called 'Mandingo'. Found in Mali/Birkina Fasso, but spreading into Senegal, Gambia and Guinea-Bissau. I got to know quite a few of them when I visited Gambia, Senegal and Mali:
https://en.wikipedia.org/wiki/Mandinka_people
The great albino singer Salif Keita is Mandinka:
http://www.youtube.com/watch?v=2BrmC_Cplrg
Thanks Terry. I was wondering if it was them. But I have never heard them called Madenka before.
ReplyDeleteThanks for the links. Nice tutorials aimed at lay people.
ReplyDeleteI just watched all of these videos.
ReplyDeleteIt seems that the consensus is that modern humans evolved in Africa, and there was some minor mixing with other populations after leaving Africa, and possibly also within Africa.
The evidence presented seems undeniable, although the interpretation could change a little bit with unforseen additional discoveries (such as a diverse ancestral group of modern humans somewhere other than Africa, that migrated to Africa before leaving again).
So (as I really don't know that much about these things), I would like to know if there are any reasonable, non-racist, arguments against the "mostly" out of Africa hypothesis presented in these talks.
1. Last part of the last video. While the y-dna root and mtDNA root exist in what's currently in africa for other genetic clades it's not the case. Meaning your root ancestor there is in neanderthals in some cases and in asia in other cases. Significantly, your brain is x-linked and the root for neanderthals is on X.
ReplyDelete2. Go back just 10 generations and you have 1024 ancestors, 1022 of which are not represented by your Y-DNA or mtDNA.
3. Selection. Y-DNA male specific markers relate to male specific parts and hormones. They are not just a random marker, and that means they could be massively overrepresented in results. Meaning you are retaining this part but possibly basically nothing else in some or even most cases. Goes double for mtDNA as it's the basic structure of energy productions.
4. Just because something's in africa now, doesn't mean it always was. To me current locations of dna groups seem to radiate out of india andd iran. It's widely said that r1b very recently moved to spain though it seems to be most heavy there. However for africa the opposite logic is used as proof of origin. So presumably it migrated west in a way that made it look like it's migrating east. And we get this same issue with most of the haplogroups. We know natufians had E dna for example. So if there's out of africa why did they go in to africa? Ditto for austronesians. It is bound to happen sometimes but this has to be taken as the norm for OoA theory to make any sense. The biggest similarity I see to black africans is the south indians and the austronesians. They seem to have radiated out from india so presumably they moved entirely out of africa then radiated out of india and got to the middle east in just the right proportions. Clyde Winters posted in another post here and was convincing but while he seems to think that the early indians came out of africa I think likely it's the other way around and that's why they are separated by such a distance.
5. Bantu expansion. Nowadays africa is black, but even 200 years ago that was not the case. Black africa was really just the congo area, cameroon and nigeria.
(due to length blogger made me split this post up)
ReplyDelete6. No cave art in africa until very recently, compared to 40k to perhaps 55k for some art in europe. This tells me this is when the san showed up.
7. Lack of ancient skulls with black african features in africa. There's maybe some 10k years ago but that's it, all the east african ones look rather middle eastern.
8. All the finds for early homo are in NE africa and they show up suddenly, like they came from ME over south land bridge.
9. http://en.wikipedia.org/wiki/Homo_rhodesiensis Homo Rhodiensis. This dates from about 300k years ago to about 125k years ago. Now it might make up part of human genome and this may be what Hammer is talking about but this means in africa at the same time as modern looking humans we have these guys who are among the most archaic looking hominids ever found.
10. There's no hominid in africa with a modern sized brain before homo sapiens just shows up. Neanderthal had larger brains. Peking man had only slightly smaller brains but seems to date back as much as 500k years or even 750k years. Comparing to the rhodiensis skull it looks many times more modern. Basically there's absolutely NO archaeological evidence for out of africa or really for any form of evolution in africa. It all comes from the mtDNA and Y-DNA evidence. All the fossils are too archaic compared to other fossils that are earlier or in sebida's case don't come from homo at all. That's why there was no out of africa theory before then, and I believed it too for a long time but now that we know there's outside admixture and that I have looked closely at the archeology, and that new stuff has come to light outside africa it seems like a completely busted theory to me.
11. The A00 root clade in africa is found in cameroon, right where 15k years ago a big migration of r1b (and with it neanderthal DNA) occurred. Neanderthal hangs right off a00, this could come from neanderthals.
12. Molecular clock. I think this is mostly BS. But if it IS true it means that haplogroup replacement happens very fast. So in essence it doesn't mean anything.
13. No cities. To me this is a no brainer.
So what do I think now?
I think things happened multiregionally but with endless waves of migrations mostly originating in india and iran, slowly but surely replacing the mtDNA and y-DNA of previous migrations with new ones but retaining much of the genes of the previous immigration round through natural selection. The Bs of west africa spread before humans had boats and so didn't make it to america like the austronesians and siberians did and eventually got rather washed out and cornered in africa before discovering farming.
And no my interest in this is not racial in the least, or political like a lot of the studies or even most seem to be. My interest is mainly in neanderthals but also general interest in ancient civilizations.
Yes, and also, one I had to snip, sorry.
ReplyDeleteSo the biggest thing in Hammer's presentation was the evidence that there had been a big admixture with some archaic species in africa. So if homo sapiens evolved in africa in the first place this is pretty much nonsensical. That pretty obviously means that modern looking humans of some kind were just entering africa for the first time, otherwise it means they stayed in the north east corner of africa for 100k years all to themselves before going to subsaharan africa, but wait, until now we are told sub saharan africa is where every human evolved.
Anyway, I guess this theory won't die for political reasons, but honestly I don't think it's a flattering theory to african americans anyway. Almost racist because it implies everyone evolved from an african, as if they are an archaic human form which I don't believe is the case.
Oh boy looks like none of my wall of text got through so I'll give the short short version.
ReplyDeleteNo one denies the Y-DNA and mtDNA are older in some african populations. However that doesn't actually say anything about where people evolved. It's a big assumption to think everyone evolved where they stood but in everywhere but africa we see that's not true.
The fossil record gives no support to OoA either. Teeth in west europe have perikymata (striations) in similar proportions from neanderthal times. So do asians (much less), and modern africans and ALL early homo in africa have none at all. So if there was a migration out of africa somehow it had no impact of any kind on the fossil record.
And somehow the super "robust" rhodiensis that the guy in the video is talking about in the video as introgressing into africans evolved side by side for millions of years without impacting it.
And there's still no evidence of a hominid with a chin that would account for it suddenly showing up. Not only in africa, but anywhere. Eventually we'll find a human ancestor with a chin and the mystery will be solved.
So nope, there was no massive out of africa. The time they appear is the time when modern looking humans arrived from elsewhere right on the border to the levant. Humans didn't evolve on a tiny narrow strip of land that's just where the archaeology is being done and where it's easy to date your finds.
@Grognard. Please do not post back-to-back comments again. Try to fit all your thoughts in ONE comment, or at most TWO if you have to. Posting four long back-to-back comments is definitely against blog policy.
ReplyDeleteSorry but I had to split them into 3, it kept failing to post. The 4th was only because you'd posted again and approved other comments but not those so I thought they had been lost.
ReplyDeleteI'm just telling you the rules. If I see 3-4 back-to-back comments again from the same person in the same post, there is a non-trivial chance that I will delete them.
ReplyDelete