Non-Africans Are Part Neanderthal, Genetic Research Shows

[mke2686]

http://www.sciencedaily.com/releases/2011/07/110718085329.htm

I honestly don't know what to say...

 

[pjoa09]

I share traits with Neanderthals and I am sure many people do. It's more of a South-West Asian and/or Middle Eastern thing.

You can spot the receding forehead on Albert Einstein himself.

 

[420MuNkEy]

I wouldn't be surprised if similar things were true of each distinct race of humans.

 

[Jordan~]

Maybe we didn't just genocide them, then. That's nice.

 

[Architect]

Interesting. I know that Neanderthal DNA sampling has been something they've been doing recently. Surprisingly some of those old bones buried deep in the caves has been yielding some DNA.

Inbreeding between the species has long been speculated, good to have some confirmation.

 

[EditorOne]

Beyond interesting. This is fascinating. Potentially dangerous and sure to be subject to various agendas, but fascinating just the same.

I wonder which of us have the alien genes?

 

[blarg]

I'm pretty sure most of society is part-Neanderthal.

 

[OrionzRevenge]

Beyond interesting. This is fascinating. Potentially dangerous and sure to be subject to various agendas, but fascinating just the same.

Yeppers

 

[Vrecknidj]

Some of the human X chromosome originates from Neanderthals and is found exclusively in people outside Africa, according to an international team of researchers led by Damian Labuda of the Department of Pediatrics at the University of Montreal and the CHU Sainte-Justine Research Center.

X chromosome eh? Not Y?

Fascinating.



Dave

 

[Cavallier]

^Not really a surprise there. The X chromosome carries more information on it.

I've got a few old Anthropology profs that must be peeing their pants with joy.

 

[Artsu Tharaz]

What are the implications of this?

 

[warryer]

Racism comes to mind as I'm sure it does for many of you.

 

[Artsu Tharaz]

Racism comes to mind as I'm sure it does for many of you.

Racialism certainly does. I'm not sure how racism will be effected.

Is this mixing of species in non-Africans grounds for superiority claims? e.g. non-Africans were able to make the best of both sides and thus surpass?

 

[OrionzRevenge]

^^^Genetic advantage to humanoid co-mingling is a valid question worth further research, and this will entail finding out how (if at all) the variations in the X chromosome impact the individual. Generally speaking, genetic diversity is a good thing. Especially given that Humans suffered a very narrow genetic purge when they where once squeezed, by Ice, to the very southern tip of Africa.

We (African Gene-Set) are naked sweaty bipedal apes so that we may look over top the tall grass of the African Serengeti, Spot a prey animal, and then jog at great length pushing the prey forward until it has a heat stroke under the Equatorial Sun. In this way, the African had not want nor need for anything else.

When humans pushed into the vastly different environments outside of Southern Africa, the stress ransacked the genetic luggage for any advantage. (Lightly Pigmented Skin to absorb vitamin D, Round-Shafted Hair that will lay flat and hold heat. As Examples).

Looking at it from this POV, there is a chance doing the wild-thing with Neanderthals was advantageous.
...but this will have to be scientifically resolved.

 

[Jordan~]

If we interbred with Neanderthals, presumably we also interacted with them. I think the fact that Neanderthals had been living in Europe for a long time before the arrival of Homo sapiens, and consequently knew how to get by there, shouldn't be ignored - we may have learnt something from them. Though there's a lot of disagreement about how mentally sophisticated they were (no one seems to be able to agree how to interpret the evidence - it ranges from Neanderthals having complex religions to Neanderthals being bipedal chimps), they certainly had strategies for surviving in Europe on top of their natural adaptations, which, if we had peaceful interactions with them, we may have been able to develop further. It's also likely that Neanderthals with whom we did have peaceful interactions would have survived better - both because we weren't killing them, and (assuming they were less mentally sophisticated than we were) because exposure to a more mentally sophisticated species increases one's own mental sophistication, as with domestic animals (parrots that can conceive of 0, for example, or chimpanzees able to use symbolic language).

 

[systembust]

Is this mixing of species in non-Africans grounds for superiority claims?

Not according to any connotations that "Neanderthal" society has carried, up until today (at least in contrast to Homo Sapiens).

"Neanderthals Were Actually Pretty Neat, After All" articles to start appearing in 3... 2...

 

[Words]

Racialism certainly does. I'm not sure how racism will be effected.

on a large international scale? I doubt much. the presence of other social boundaries (nationality, gender, economic class) are far too obvious and current than some vague prehistoric distinction.

 

[pjoa09]

Not according to any connotations that "Neanderthal" society has carried, up until today (at least in contrast to Homo Sapiens).

"Neanderthals Were Actually Pretty Neat, After All" articles to start appearing in 3... 2...

That has already been done. They reportedly have a larger brain than the Cro-Magnons (our closest primitive human) and were more courageous.

You could read courageous as stupid.

On the downside, short and couldn't really talk due to hardware issues.

Other than that they were just like the Cro-Magnons.

I believe I have prehistoric ancestors who were Neanderthals and that Neanderthals just grew along side the Cro-Magnons.

 

[Vrecknidj]

... and were more courageous.

So they are from Gryffindor.

Interesting.



Dave

 

[EditorOne]

Just because there was genetic mixing doesn't mean everything was peachy keen and ticketyboo like a prehistoric Woodstock. There is genetic mixing, forced and unforced, every time cultures collide violently. If you want a very small-scale example, some Plains Indians raided other tribes, killing men but taking women, who were assimilated into the conquering tribe's numbers as slaves and wives and full members, depending on variables I don't pretend to understand. They did that with European settlers, as well, and the offspring were regarded as full-fledged members of the Native American unit regardless of genetic nonconformity. Several chiefs among Cheyenne and Sioux were half white; some white women who were captured as children ran back to Native American culture after being "rescued" or negotiated loose from the tribe as part of peace talks. All this atop a foundation of violent interaction, tribe to tribe and culture to culture, in the case of European settlers. This might be one way things worked out with Neanderthals. Just tossing it out for people to roll around in their minds.

As noted, fascinating stuff.

 

[scorpiomover]

So they are from Gryffindor.

But then they bred with the Slitherins. The Griffindors disappeared, and the Slitherings took over the planet.

Harry Potter must be turning over in his coffin.

 

[Jordan~]

Just because there was genetic mixing doesn't mean everything was peachy keen and ticketyboo like a prehistoric Woodstock. There is genetic mixing, forced and unforced, every time cultures collide violently. If you want a very small-scale example, some Plains Indians raided other tribes, killing men but taking women, who were assimilated into the conquering tribe's numbers as slaves and wives and full members, depending on variables I don't pretend to understand. They did that with European settlers, as well, and the offspring were regarded as full-fledged members of the Native American unit regardless of genetic nonconformity. Several chiefs among Cheyenne and Sioux were half white; some white women who were captured as children ran back to Native American culture after being "rescued" or negotiated loose from the tribe as part of peace talks. All this atop a foundation of violent interaction, tribe to tribe and culture to culture, in the case of European settlers. This might be one way things worked out with Neanderthals. Just tossing it out for people to roll around in their minds.

As noted, fascinating stuff.

I did consider as well that it might not exactly have been the most peaceful of interactions that led to interbreeding. In the absence of definitive evidence I prefer to think that it was peaceful, though - it remains now to see if any sites can be found (or reinterpreted) displaying signs of H. sapiens/H. neanderthalensis cohabitation. Of course, it would be impossible to prove that there were no such sites, but it would be possible to conclude if none were found that if cohabitation did occur, it was extremely rare. It'd also be interesting to see how groups were mixed, if there was differential burial practice, etc.; and to look for elements of syncretism between Neanderthal culture (if they had something that can properly be called culture - again, opinions on that are very varied) and the culture of the invaders. Are burial practices transmitted from sapiens to neanderthalensis or vice versa? Is technology shared? Do artistic styles change? Do Neanderthal groups become more culturally complex after exposure to Homo sapiens? There are plenty of ways to test the nature of the comingling.

 

[Agent Intellect]

I'm interested in what sort of sexual selection may have taken place between Neanderthals and Homo Sapiens. As a person opinion, I don't find the artist renditions of Neanderthals very attractive, and I can't imagine that a lot of other people do, either. Being that it was early on in the evolution of Homo Sapiens, I wonder if what was considered sexually viable wasn't as narrow as it is today? There is a hypothesis that as a species diverges, the sexual selection of individuals gradually becomes narrower, essentially seeking out those that are archetypes (or even caricatures) of the opposite sex* (eg the so-called "perfect" female being 34-24-34 inches (86-60-86 cm) for breast/waist/hip and at least 5 ft 8 (1.73 m) tall (1)), so I wonder how long this takes to evolve?

It also makes me wonder, if the inter-species intercourse was non-consensual, which species was the one doing the raping? From what I understand, it's generally assumed that Neanderthal's were more physically strong, so it's possible they were the ones taking captives and impregnating them.

*I read this a while back in a Scientific American, so I don't have a source, nor do I remember what they called this hypothesis.

 

[Jordan~]

This and other such figurines are pretty much all we have to go by for the notion of the ideal female held by Homo sapiens in Europe around 30,000 years ago. Obviously the characteristics are exaggerated, but that may tell us what the artist considered important - it may be emphasis through exaggeration. The distinctively 'female' attributes are very exaggerated - the breasts, hips, thighs and buttocks. I don't think it would be unreasonable to suspect that these were features of the ideal of feminine beauty. Additionally, very few of the figurines (there are an awful lot of them like that) have faces, despite the fact that faces are sometimes represented in other artwork. Maybe the face wasn't that important to them? It's hard to say, though; if these statuettes are religious in nature, as some think, there could have been a taboo against representing the face of the goddess (or whatever it was), or she may have been imagined to have no face. Some are also highly stylised, some have a prominent clitoris and labia.

 

[cheese]

Looks like the stomach was of paramount importance.

 

[systembust]

Phew - did it just get hot in here?? What, no NSFW spoilers on this board??

 

[SkyWalker]

Looks like the stomach was of paramount importance.

haha

this picture represents fertility, because fat=surplus.

it does not represent attractiveness!!!! dude, i dont know what your taste is, but that chick is fat and ugly! And even 50,000 years ago I would still agree on the fact that she's fat and ugly!

 

[Aramea]

I would say that is quite safe for work if my coworkers are any indication. Not very, um ... titillating. Is that a fro or a knitted cap on her head? I wonder if they had a type of noble or royalty given how fat she is. It is difficult to imagine food being consistently easy to come by. On the other hand, perhaps that is what made her frame so attractive to them in a "will survive the winter" kind of way.

 

[systembust]

On the other hand, perhaps that is what made her frame so attractive to them in a "will survive the winter" kind of way.

As an INTP, that's actually pretty high on my list of criteria for a potential mate.

 

[Jordan~]

haha

this picture represents fertility, because fat=surplus.

it does not represent attractiveness!!!! dude, i dont know what your taste is, but that chick is fat and ugly! And even 50,000 years ago I would still agree on the fact that she's fat and ugly!

I'm gay. :P

Fatness is attractive during lean times, don't you know? We'll never see another lean time again here in the west, so our stick-thin standard of beauty is likely to stay around, but a glance through changes in artistic styles over the millennia will quickly reveal that the waistlines of beauties expand and contract over time.

Aramea makes a good point: She would survive pretty well in the freezing north, wouldn't she? I'm certain it's an exaggerated representation, as I doubt anyone would have been allowed to get that fat where food was presumably fairly scarce (though I seem to remember reading an article that presented evidence that H. sapiens populations migrating into Europe actually ate surprisingly well).

The hypothesis that I'm putting forward isn't that this statuette as it appears was an ideal of beauty, it's that the exaggerated features on this statuette (and its many counterparts from elsewhere in Europe over the next 20,000 years or so) were integral to the ideal of beauty at the time. That is, if it's big on the statuette, it's 'big' in their minds.

@Aramea: It may be a representation of her hair, or just a pattern in place of the 'unimportant' head, which the artist obviously didn't care to spend much time on. It's highly unlikely that they had any form of nobility; at this point it's unlikely that they had rigid hierarchy at all, though tenuously possible that they may have been developing stratified social organisation in very resource-rich areas. There is some debate surrounding it, but I think even those who most staunchly propose that their societies were hierarchically organised would say they only had a chief. Differential status (or differential prestige) is indicated by burial practices, though.

This segues neatly into an interesting point: it's thought (by analogy to modern hunter-gatherers) that the division of labour between the sexes in the Palaeolithic was fairly flexible - women may have assisted in the hunt and men may have assisted with gathering. There don't appear to be more men in high-prestige graves than women, and indeed, the first identified shaman figure discovered (from 30,000 years ago) was female. It's quite possible that Venus figurines were made by women.

Anyway, with that in mind; obviously, as I say, she's exaggerated out of proportion. Some Venus figurines are less so. This is probably best interpreted as exaggeration for emphasis, which I touched on briefly in my last post.

The maker of the figurine has no way of letting the viewer know which parts of the woman are important without making them huge - hence the enlarged vulvas, labia, clitoris etc. on certain figurines (on which note, how can this not be 'work safe'? I sat through a lecture that was basically slide after slide of these things for an hour, that's someone's work) to emphasise, "Look, these are the important bits of a woman, this is where reproduction happens". That is understandable. But they're not just depicted with emphasised lady bits (as in the case of this one: sometimes the lady bits aren't marked except as a pubic triangle - I posted this one because it's the oldest). In those that are, why should other parts of the body be enlarged in the same way? What is the artist thinking when they decide to emphasise the buttocks, the thighs and the breasts in the same way as the reproductive organs?

That it's a visual metaphor for fertility is an obvious answer, yes, and supported by the fact that many figurines appear to be otherwise fat, too. Many are not, however - quite a few are slender, but with certain exaggerated attributes (again, buttocks, thighs, breasts, and sometimes reproductive organs). It's surely a visual metaphor, but what for? These are the only depictions of females (and some of the very few depictions of humans) that exist from the time, and consequently, whether they were considered attractive or not (I don't think they were either, I'm suggesting that they may have been a guide to attractiveness, a sort of blueprint - "If she's got these bits good, she's a keeper") they are the only evidence we have of the perception of women during the time of H. neanderthalensis/H. sapiens mingling of any form at all, thus their interpretation will be important to understanding the nature of the interbreeding in some way. I'm putting forward a tentative hypothesis that:
- The exaggerated attributes on Venus figurines - whether they were carved as idealised female goddesses, pornography (it's been suggested) or self-portraits by women (again, it's been suggested) - correspond to the attributes of a woman considered important to the ideal of feminine beauty among H. sapeins 30,000 years ago.
- H. neanderthalensis females possessed, or were capable of possessing, such attributes.
- Consequently, H. neanderthalensis females could be considered beautiful by H. sapiens.

I'll put this in a spoiler tag for potential NSFW-ness, but Jesus, grow up, it's science!:

Spoiler

This is a reconstruction of a Neanderthal woman. Rather Venus-y, no?

A final point: Death in childbirth was an impediment to the evolution of increased cranial capacity in the genus Homo. We have giant, giant heads, and that puts a certain strain on mothers in childbirth. To compensate, we have to be born slightly underdeveloped and consequently we're dependent on our parents for a proportionally longer time than many other animals. Neanderthal anatomy is better suited to dealing with difficult births due to the shape of the pubis, and they were generally only around 13cm shorter than modern humans on average. Additionally, Neanderthal children appear to have reached adulthood slightly faster than H. sapiens children. This creates an obvious biological advantage to mating with a Neanderthal female: she's more likely to survive the childbirth, and the child may be less of a drain on resources. However, note that the first advantage is only an advantage if the male is pair-bonded to the female, indicating a consensual relationship and thereby implying peaceful interaction. Just another idea I thought I'd throw out there.

A really final point: Sould we be calling them H. s. neanderthalensis now?

 

[systembust]

I'll put this in a spoiler tag for potential NSFW-ness, but Jesus, grow up, it's science!

For the record, I was *completely* joking. As much as I hate emoticons, I'll obviously need to start using them.

 

[Jordan~]

I was, too, don't worry. :P That was something you might get in trouble for if you looked at it at work. If you work in a nunnery.

 

[Architectonic]

This study didn't actually measure Neanderthal DNA, but derived the conclusion from the geographic distributions of (X-linked) dys44 polymorphisms, which were apparently similar to those of Neanderthal DNA from a previous study (Green 2010). In particular, the distribution of the B006 haplotype, is fairly common outside (but not inside) of sub-Saharan Africa, (and particularly common in the Americas).

This hypothesis is still speculative - you have to remember that we share genes with Neanderthals anyway due to common heritage, so it could be possible that this is just an artefact of having a small isolated population move out of Africa.

 

[cheese]

Hahahaha

Jesus, grow up, it's science!

This could be taken in more ways than one.


Also, RE the stomach - I thought it was worth noting because stomach fat actually *doesn't* indicate fertility, though it would indicate resources... the thighs, buttocks and breasts would be most important as these are estrogen indicators.

With the reconstruction of the neanderthal woman - I don't see her as being particularly venus-like at all; her breasts are average, her legs and butt are chunky but then again so is her waist. And it's the waist-to-hip ratio that tends to indicate estrogen better, rather than just being fat overall.

Maybe it's about resources, then, rather than fertility.

 

[420MuNkEy]

That figurine looked like a Chinese Fleeceflower root.

Spoiler

 

[Agent Intellect]

This study didn't actually measure Neanderthal DNA, but derived the conclusion from the geographic distributions of (X-linked) dys44 polymorphisms, which were apparently similar to those of Neanderthal DNA from a previous study (Green 2010). In particular, the distribution of the B006 haplotype, is fairly common outside of sub-Saharan Africa, (and particularly common in the Americas).

This hypothesis is still speculative - you have to remember that we share genes with Neanderthals anyway due to common heritage, so it could be possible that this is just an artefact of having a small isolated population move out of Africa.

Indeed, the original article is more interesting and informative. Secondary sources are prone to sensationalism.

 

[Jordan~]

This hypothesis is still speculative - you have to remember that we share genes with Neanderthals anyway due to common heritage, so it could be possible that this is just an artefact of having a small isolated population move out of Africa.

At any rate, it's fun (and, for me, good practice) to speculate. :P

Also, RE the stomach - I thought it was worth noting because stomach fat actually *doesn't* indicate fertility, though it would indicate resources... the thighs, buttocks and breasts would be most important as these are estrogen indicators.

With the reconstruction of the neanderthal woman - I don't see her as being particularly venus-like at all; her breasts are average, her legs and butt are chunky but then again so is her waist. And it's the waist-to-hip ratio that tends to indicate estrogen better, rather than just being fat overall.

Maybe it's about resources, then, rather than fertility.

Ah, right, I thought you were joking. Well, the stomach as fertility indicator (it wasn't me who said it, I think) is a visual metaphor for fertility - the land is fertile and so the embodiment of the land is fat; obesity is an indicator of abundance of food, abundance of foo is an indicator of fertility. But I'm sceptical that it's a goddess, anyway; it seems... too early for deities, I think they're more likely to have been animists. Plus, there were settings that have been interepreted as religious where contemporaneous material culture has been found; to my knowledge there were no Venuses among it.

Her waist is chunky to indicate Neanderthal bone structure, I think - they had barrel-shaped torsos. They also had very thick limbs; in general they were a lot more robust than we are. She may actually just be big boned, literally.

She doesn't need to resemble the figurine itself - she's not that curvy - but rather, the features emphasised by exaggeration on the figurine need to be prominent. I think they are more prominent, which is the important thing for the purpose of arguing about whether or not H. neanderthalensis (H. s.?) could have been attractive to H. sapiens, than they would be on a female H. sapiens of the time (as they're reconstructed, anyway). Our limbs are longer and thinner to begin with, we have torsos that are flat or slope down from top to bottom, and it's not very likely that many of us would have had the opportunity to get fat.

 

[Dimensional Transition]

This is interesting. The question now is: What are we going to do with this information? Is it useful in some way?

It gives us some insight in how we developed, but is there anything more? Does this open up new possibilities, drastically different and new theories?

 

[Jordan~]

It's primary use, I think, is as evidence of the nature of human societies during the Upper Palaeolithic. This is important in itself because a clear picture of very ancient societies can be incorporated into the corpus of various sciences and academic disciplines - not just archaeology and anthropology, but also history, ecology, sociology, evolutionary biology, int. al. - where it may lend support to existing theories or contribute to the development of new ones. Of course, it still requires interpretation to be of any value, except perhaps to geneticists.

 

[Roni]

Paleoanthropology was my big passion early-mid nineties (and yes Jordan, we were using H. sapiens neandertalensis even then (and the 'tal' instead of 'thal' was a bigger quibble point than sapiens v not sapiens)) but I've completely lost touch since then.

The main thing that struck me about this article was the unquestioned acceptance of the Out of Africa model. Last time I checked that was still contentious. Applying my out-of-date prejudices I went pfft at 'sub saharan africa' since the Sahara was no impediment to migration 12000-5000 bp and so deductions about human distribution 30000 bp from modern african populations is dodgy at best....

... but I was so very into this topic back then that I'm still terrified some 'real' anthropologist is about to jump all over me for that last paragraph, so it's time for me to slink away ...

 

[Jordan~]

In all of my lectures they were H. neanderthalensis; but I suppose it would have depended on who you asked. If there's clear evidence that they're a subspecies of H. sapiens then I suppose they have to be called H. s. neanderthalensis now (or H. s. neandertalensis, but that's just to do with German spelling reform; when the species was named, the German word for 'valley' was spelt 'Thal', and I don't see any reason to retroactively correct the spelling).

Those objections to the Out of Africa hypothesis are answered by the Sahara pump theory, aren't they? I'm only a first year student, so I don't know that I'd call myself a 'real' anthropologist, though. :P The alternatives to Out of Africa were raised at lectures, but Out of Africa seemed to have extremely strong (genetic, especially mtDNA) evidence behind it, the objections seemed to have answers and the alternatives seemed to have some flaws.

That said, this could throw some support behind a multiregional hypothesis; but it still appears that H. s. sapiens (us) originated in Sub-Saharan Africa, even if we did then interbreed with other subspecies. The multiregional hypothesis, as I understand it, holds that modern humans are the result of the convergence through interbreeding of several H. sapiens subspecies including an African one that evolved throughout the world, rather than a result of H. sapiens sapiens emerging from Africa and then replacing the other subspecies. It's still possible that we replaced other subspecies through interbreeding, is it not?

I guess it rather hinges on whether or not H. erectus could produce fertile offspring with archaic H. sapiens, since the multiregional hypothesis requires that they're a single, continuous species undergoing interregional gene flow.

 

[Reverse Transcriptase]

So, this is like... super relevant to this thread. The person here has a theory about the neanderthal/human interaction.

The idea is that: yes, there was some inbreeding. But what makes (non-african) humans even more human, is a tens of thousands of years long battle between us and neanderthals.

http://www.youtube.com/watch?v=mZbmywzGAVs

 

[Roni]

@jordan
I was a passionate layman but a layman nonetheless, so yeah, 1st year student counts as 'real' anthropology and I'm suitably intimidated. I've just had a quick wikipedic refresher though, so I'll try to be brave

While I was sleeping it appears H. heidelbergensis finally found a starring role which explains why the Neanderthals lost their sapiens title. If this new information bumps them back to H. s. neanderthalensis (grizzle grizzle) what becomes of Heidelberg Man?

I'll restate my Out of Africa gripe since I can see now my last one made no sense.
What bugs me about specifying 'sub-sahara african' in the context of living people is the assumption that migration only goes one way - we started in Africa and picked up some Neantherthal DNA as we moved through Europe and populated the globe and - lookit! Here's proof in the populations we left behind!
And maybe it's possible that's exactly what happened, but it seems very unlikely. If we could get all the way to Polynesia and South America there's no reason to believe we couldn't get back to sub-saharan africa in the same timeframe.

 

[Reverse Transcriptase]

@jordan
I was a passionate layman but a layman nonetheless, so yeah, 1st year student counts as 'real' anthropology and I'm suitably intimidated. I've just had a quick wikipedic refresher though, so I'll try to be brave

While I was sleeping it appears H. heidelbergensis finally found a starring role which explains why the Neanderthals lost their sapiens title. If this new information bumps them back to H. s. neanderthalensis (grizzle grizzle) what becomes of Heidelberg Man?

I'll restate my Out of Africa gripe since I can see now my last one made no sense.
What bugs me about specifying 'sub-sahara african' in the context of living people is the assumption that migration only goes one way - we started in Africa and picked up some Neantherthal DNA as we moved through Europe and populated the globe and - lookit! Here's proof in the populations we left behind!
And maybe it's possible that's exactly what happened, but it seems very unlikely. If we could get all the way to Polynesia and South America there's no reason to believe we couldn't get back to sub-saharan africa in the same timeframe.

Thanks for being brave motivation & passion is EVERYTHING, brute intelligence and knowledge count for nothing in the long run. I'm really happy to see you trying it out.

However, I think you're wrong, and here's why. It is much easier for populations to expand into territory that haven't already been colonized by humans. The humans in europe could have migrated back to sub-saharan africa, but they would have been fighting and competing for food the whole way. Whereas, spreading slowly out to unoccupied spaces is relatively easier.

There's also the genetic argument: We can see how human lineages branched out and where and how long ago our shared ancestors were. By seeing the different "baggage" of mutations in different population groups, we can organize a human family tree. Further more, because these human groups have mostly been living in the same spaces for generations, we can put that tree onto a map, and get something like this:
http://3.bp.blogspot.com/-hV1HOLamOz4/Taus3OBULWI/AAAAAAAAADo/9xqknrgt7MM/s1600/ancestry+large.jpg

edit: oh, and another fun idea: We've tracked the speed of human migration outwards from Africa based on the earliest human bones found in different areas. I don't have the exact reference (which kills me!) but it was about 5 kilometers per generation. An easy walk for each generation.

 

[Roni]

.. It is much easier for populations to expand into territory that haven't already been colonized by humans. The humans in europe could have migrated back to sub-saharan africa, but they would have been fighting and competing for food the whole way.

Not the whole way - the Sahara would not have been inhabited 12500 years ago when it began its 7000 year period of yumminess. A lot can happen in 7000 years.
Not long after that a whole lot of archeology happened, including a Roman Empire stomping all over the boundaries of where these little gene packets were supposedly indigenous. And genes have a way of migrating even when a safe and happy population can't.

Maybe I'm not giving archeologists, historians and language experts enough credit and maybe they have mapped modern migrations so precisely we can trust that DNA from X now implies DNA from Y 30000 years ago. But even then I'd be cautious inferring much about population movement.
It's just a packet of genes in question here. If those genes caused a significant disadvantage in an african environment you would expect them to be absent from the surviving population even if they did migrate from Europe.

Cheers for the link, btw. I was interested in the Y-Chromosome stuff. Was there an article associated with that?

 

[Jordan~]

Both hypotheses are probably oversimplifications of what actually happened. Just pick any ancient civilisation and look at population movements, expansions and contractions of its borders, who's in charge and who isn't etc., and consider how relatively short the length of time you're looking at is compared to the timespan of human migration, and it's obvious that it almost certainly wasn't so simple.

I suppose it's best to think of the two hypotheses as tendencies rather than complete visions of what happened.

 

[dialectical_stew]

From my basic understanding of evolutionary anthropology, aren't most persons in the field confused as to why neanderthals didn't become the dominant species due to their evident superiority, both intellectually and physically?

 

[Jordan~]

I don't think anyone argues that they were intellectually superior. It's far from certain that they could speak. The only estimations of their intelligence I've heard and read range from 'glorified gorillas' to 'a tiny bet less than sapiens'.

The language question is important if language enables metaphor, which vastly increases a species' ability to conceptualise and understand the world. Though it's conceivable that metaphorical thinking is possible without language. But how else would it be communicated?

 

[dialectical_stew]

I stand corrected. Oops. I blame the internet.

 

[systembust]

It's certainly an interesting topic. Much to digest.