The big teeth of Neanderthal toddlers
At 18 months, Neanderthal children already had big teeth, larger than those of modern humans. The new finding of a lower jaw, at a Belgian cave, by Isabelle Crevecoeur, belongs to the youngest Neanderthal specimen ever found and already possessed Neanderthal traits, such as a strong jaw and big teeth.
While the kid had thinner enamel than would be found in modern humans of similar age, it already shows a clear early growth spurt in comparison to our species, starting this development maybe as early as 12 months old.
The research is scheduled to appear in the Journal of Human Evolution and has already the blessings of famous Neanderthalist Erik Trinkaus, who thinks that the conclusions are well-reasoned and reasonable.
Were the ornaments of Grotte du Renne made by Neanderthals?
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| Ornaments from Grotte du Renne |
According to Randall White the layers are so mixed and convoluted that it is impossible to say. However João Zilhão argues that White's evidence says exactly the opposite. Zilhão has in the past also clashed with other researchers on stratigraphic issues related to Chatelperronian, Neanderthals and the MP-UP transition in SW Europe.
Critically the earliest research of this cave, by Leroi-Gourham, found many Neanderthal teeth in the Chatelperronian layer, that is arguably intermediate between Mousterian and Aurignacian. However recently there has been some questioning of the attribution to Neanderthals of the Chatelperronian industry.
The case is that dates obtained from Chatelperronian materials range from 49,000 to c. 21,000 years ago, when Neanderthals are already thought to have been completely extinct for some 10 millennia (longer locally).
If this interpretation of White is correct and Chatelperronian effectively happens to be an industry of Homo sapiens, then it would be a lot easier, specially with such late dates as 21,000 BP, to trace the origins of Gravettian industry, whose closest relative is no doubt Chatelperronian (both were originally described as Perigordian and only lack of direct evidence for continuity broke down that category in two eventually).
Zilhão's counter-argumentation seems to go along the lines of most dates at Grotte du Renne being consistent with known Neanderthal presence (i.e. in the oldest range). I would say that, if the oldest date is just 49,000 BP, this fits completely well in the model that argues that all UP technologies in Europe, including Chatelperronian possibly, are the work of our species, because these technologies only appear since c. 49-48,000 calBP and more strongly since c. 44,000 calBP.
Source: Science (free article).
Ref. Thomas Higham et al., Chronology of the Grotte du Renne (France) and implications for the context of ornaments and human remains within the Châtelperronian. PNAS 2010 (pay per view, varying on location and time of retrieval).
Pretty much any time carbon dates in the 30k to 45k range are re-analyzed using the modern filtering technique, and when properly corrected, they turn out several 1,000 years older than previously thought. It seems clear now that from (nowadays) Italy to Germany to the Ukraine, modern people started living there by at least 43k years ago.
ReplyDeleteI have no idea why some people still insist that Châtelperronian or Ulluzian are Neanderthal. The fact that this "in-between" period does not show the full cultural basket of the Aurignacian is easily explained by thinking about it as the "frontier region" - people were more transient, perhaps often groups of males, only - similar to frontier regions through history.
I can understand well the claim that Chatelperronian is Neanderthal-made: after all all the remains related are Neanderthals, even if some are stratigraphically odd.
ReplyDeleteThe Uluzzian is another story. I don't know too much but da expert no. 1 says that Uluzzian is traditionally considered Neanderthal because of several milk teeth, whose adscription is controversial anyhow.
In any case, when you realize that more than 95% of all the population in late UP Europe was concentrated in the Magdalenian area, all the rest looks somewhat irrelevant by comparison.
The details of the transition are not too clear but maybe it is not so important after all. In the end it is about (not) knowing the details of how some 5000 people (Neanderthals) were replaced by some other 5000 people (H. sapiens) [1800-28,000 with CIs]. That they were replaced is clear, because the Frenchman and the two CEU samples, which should be descendants of the late UP population largely, compare equally with Neanderthals as other Eurasians.
Otherwise the transition may well have lasted until Gravettian times. More intriguing to me of all is where did Solutrean come from or how was it conceived? It seems to have no precedents other than the MSA itself, right? Well... time machine and solved. ;)
I agree with you that this is a difficult time period - and I also agree with the second-to-last paragraph in Riel-Salvatore's blog entry that you cited.
ReplyDeleteBut from a conceptual viewpoint, while Neanderthals likely were quite smart and likely had certain advanced characteristics AMH's did not have or only to a lesser degree (including cognitive), for me the easiest interpretation is that of significant separation between the two groups -- even if not always in space and time -- and if it quacks like a duck...
...meaning that culturally advanced layers should be assumed to be AMHs unless there is strong, irrefutable evidence otherwise.
To me, those portions of Châtelperronian or Uluzzian that show advanced tools and other advanced signatures are not supported by such strong evidence. It's a transition period, so, mixture is a given, but does not necessarily mean mixture in culture(s) nor people. The most likely cause of "mixture" is stratigraphic perturbation.
Could be, I have indeed explored that line of thought... but it would be much more solid if more fossils clearly supported it and stratigraphies were more clear. Right now all the hard core evidence for H. sapiens manufacture of anything in Europe before Gravettian is the Pestera skeleton (no context) and the remains of Ahmarian (Palestine), which is likely precursor of European Aurignacoid industries.
ReplyDeleteSo the evidence is scant in both directions. I can't but remain prudent. I wish I knew though.
Ey, you finally splited the blog in two!
ReplyDeleteI'm linking that one right now in my own blog.
I doubted to do it before, with Leherensuge, as you dealt with too many different issues (politics, ethics, conflicts...), besides paleoantropology and Archaeology.
About the new dates from Grotte du Renne, i' ve a preliminar opinion (thumbs up for data, thumbs down for conclusions). But i do REALLY need to invest more time in a careful reading of the paper, before making mind.
Nice post!
ReplyDelete"At 18 months, Neanderthal children already had big teeth, larger than those of modern humans. The new finding of a lower jaw, at a Belgian cave, by Isabelle Crevecoeur, belongs to the youngest Neanderthal specimen ever found and already possessed Neanderthal traits, such as a strong jaw and big teeth."
I also noticed that neanderthal children (such as Teshik Tash) tend to have very large front teeth. I don't know why is this, and if it's a norm for all neanderthal infants.
"Zilhão's counter-argumentation seems to go along the lines of most dates at Grotte du Renne being consistent with known Neanderthal presence (i.e. in the oldest range). I would say that, if the oldest date is just 49,000 BP, this fits completely well in the model that argues that all UP technologies in Europe, including Chatelperronian possibly, are the work of our species, because these technologies only appear since c. 49-48,000 calBP and more strongly since c. 44,000 calBP."
This is really sad, because if true, this means we don't know anything at all!
If we assume that by 49.000 years modern humans were already in western Europe, then what happened with neanderthals? Were they incapable of innovation?
Anyway, one thing is clear: if the authors are right, the evidence for a neanderthal origin of Chatelperronian is quite weak, but by 50.000K they were already living in France and most western Europe, so they must have met each other. Neanderthals apparently survived until 25-30.000K.
There's a possibility of all dates being wrong. After all, I read some of these remains classified as Chatelperronian have been placed to a much younger date. This was also the case of some skeletons though to be "the first Europeans" and dated no more than 5.000 years.
I'd be great to find a jaw or something to identify them.
Where did these peoples bury their dead?!
@Millan: Yes :)
ReplyDeleteIt had to be done but now I find difficult to find where to post on matters that are not clearly defined, say astronomy...
@Maria Lluïsa:
"if true, this means we don't know anything at all!"
Our knowledge is necessarily limited. The details of the data may be more clear (not always) but building an interpretation on them is always problematic, more proper of the (pre-)historian than the archaeologist (even if both facets typically converge on the same people).
After all the historian tries to tell his/her best interpretation of the data, while the archaeologist in principle merely documents the data as such.
"If we assume that by 49.000 years modern humans were already in western Europe, then what happened with neanderthals? Were they incapable of innovation?"
Well we'd enter in several debates here:
1. Whether UP (mode 4) techs are in fact "superior" to MP (mode 3) ones, specially Aurignacian or, as many would argue, essentially the same: just different technological traditions.
2. Whether adopting other peoples' cultural elements is in fact innovation or mere learning (innovation implies inventing, not just copying).
3. Whether techno-cultural traditions are more techno or more cultural, i.e. if they have intrinsic technological value providing an effective competitive advantage or whether they are essentially just learned ways of doing thing with nearly zero adaptive value.
And of course (4) how effectively intelligent were Neanderthals with their low but hyper-stretched heads (intelligent in the sense of "like us", of course).
Personally I think that the key disadvantage of Neanderthals was their somewhat short limbs and stocky constitution. This probably limited their mobility/agility somewhat in comparison with us and, while not too critical on its own, should have made their competition with us quite a bit more difficult: smaller territories (documented), lesser efficiency in "rogue skills" (from hurling and running to many other little but accumulatively important things).
Additionally to that they might have got a mind somewhat differently organized than ours (not dumber, just different) but that its surely impossible to assess, because the brain is so plastic...
"Where did these peoples bury their dead?!"
Some peoples just don't. Not just some cultures practice incineration but some hunter-gatherers like the Hadza do not bury nor mourn apparently (they also do not believe in any afterlife either, they are hyper-presentist: they live to the day or almost, except for caring a lot for the children and having a clear idea of the seasonal cycle). If such practices were generalized in the past, it'd would explain why it's so difficult to find remains in some periods and places.
"This was also the case of some skeletons though to be "the first Europeans" and dated no more than 5.000 years".
I'd like to know what you are referring to here. Never heard of that actually.
"And of course (4) how effectively intelligent were Neanderthals with their low but hyper-stretched heads (intelligent in the sense of "like us", of course). "
ReplyDeleteWell, some minor differences have been found, like genes for autism and schizophrenia, but these are only 2-3 genes for the moment. Not too much. Maybe they had a more "practical" intelligence, but I don't think they were less intelligent as a whole.
"Personally I think that the key disadvantage of Neanderthals was their somewhat short limbs and stocky constitution. This probably limited their mobility/agility somewhat in comparison with us and, while not too critical on its own, should have made their competition with us quite a bit more difficult: smaller territories (documented), lesser efficiency in "rogue skills" (from hurling and running to many other little but accumulatively important things)."
When do you say "us" do you think in all modern humans, or just only Europeans? Anthropologists tend to think only in Europeans when they compare modern humans with neandertals, which is a mistake in my opinion, because skimos, for example, have a body shape quite similar to that of neandertals.
"I'd like to know what you are referring to here. Never heard of that actually"
http://www.nature.com/nature/journal/v430/n6996/full/nature02690.html
"When do you say "us" do you think in all modern humans, or just only Europeans? Anthropologists tend to think only in Europeans when they compare modern humans with neandertals, which is a mistake in my opinion, because skimos, for example, have a body shape quite similar to that of neandertals".
ReplyDeleteI think in Ethiopians in fact ;)
Seriously I think in modern humans in general because even if some are a bit odd (think Pygmies for instance), the proportions are basically the same, Inuit too. Neanderthals had shorter femurs and the corresponding arm bones, what means that their legs were proportionally shorter and that gave them a lower center of gravity (more stable). They were also very strong and stocky.
For that reason I compare them with fantasy dwarfs, a concept nearly everybody is familiar with. Like Neanderthals, fantasy dwarfs are very strong and stocky, somewhat shorter than humans and with shorter legs and arms. For that reason they are not good for the rogue role in games: they excel in strength and are ideal for close combat types but totally wrong for scouts, rangers and stuff like that.
I like the fantasy comparison because in such imaginary stories dwarfs are not less intelligent than humans but still they are different, even psychologically at times. What I do not know is if Neanderthals were stubborn, grumpy and excellent crafters, as the fantasy myths depict them typically. My comparison actually ends with the body type and the limitations/advantages that each one has.
But never mind, I quit playing such games since Shadowbane, the best online game ever, went off last year. Yet it was inspiring in this aspect: those "dorfs" were really difficult to kill but they could not catch you either (I never played dwarfs admittedly) :D
...
As for the Swabian Aurignacian people, it's interesting to know. The arrival of Aurignacian to SW Europe began at the Rhône (Ardéche), it seems, what allows for both routes. However I suspect that Northern Italy played the most important role, rather than Germany.
The biggest obstacle would be the Alps, then almost fully iced, but the coast should have been passable, specially with boats or rafts (and the arrival to Sicily of some Aurignacian shows that they did posses them). North Italy was surely also the passage of proto-Aurignacian before that.
But I was unaware of those skeletal remains anyhow. Shouldn't there be a context with them? Tools or something?
"I think in Ethiopians in fact ;)"
ReplyDeleteDo you thik they're representative of first H. sapiens?
Well, in any case it's better to compare neanderthals with Ethiopians than with modern Europeans, like many studies did, due to some Eurocentrism.
"Seriously I think in modern humans in general because even if some are a bit odd (think Pygmies for instance), the proportions are basically the same, Inuit too. Neanderthals had shorter femurs and the corresponding arm bones, what means that their legs were proportionally shorter and that gave them a lower center of gravity (more stable). They were also very strong and stocky."
I thought the Inuit had the same body proportions as neanderthals. But not all neanderthals were so stocky. There are noticeable differences between classic and progressive (Near-Eastern) neanderthals.
"I like the fantasy comparison because in such imaginary stories dwarfs are not less intelligent than humans but still they are different, even psychologically at times. What I do not know is if Neanderthals were stubborn, grumpy and excellent crafters, as the fantasy myths depict them typically. My comparison actually ends with the body type and the limitations/advantages that each one has."
Yes, maybe neanderthals couldn't run as fast as we can, after all. But for example, among the best athletes of the world, you'll find many Africans, and it's not a casuality, they can run faster than other human groups, as a whole.
"But never mind, I quit playing such games since Shadowbane, the best online game ever, went off last year. Yet it was inspiring in this aspect: those "dorfs" were really difficult to kill but they could not catch you either (I never played dwarfs admittedly) :D"
LOL, I don't know this game. I don't use to play games a lot, and I don't know whether the "dorfs" are representatives of neanderthals at all, but in any case, your comparison seems interesting.
"But I was unaware of those skeletal remains anyhow. Shouldn't there be a context with them? Tools or something?"
Yes, apparently these skeletal remains were associated with proto-Aurignacian tools, dated 40 Ka or older, but the skeletal remains turned out to be much younger than that.
I found an interesting study about neanderthal-modern human divergence. The authors studied skulls from various hominids, including neanderthals, erectus, rhodesiensis, sapiens, etc.
They found that neandertals weren't exclusively descended from an European species and H. sapiens weren't descended only from H. rhodesiensis. I couldn't read the full article, but anyway it sounds interesting and raises more questions about that study from Atapuerca scientists.
"Calvarial shape variation among Middle Pleistocene hominins: An application of surface scanning in palaeoanthropology:
The increasing availability of 3D data and tools offers new analytical perspectives in palaeoanthropology, such as the quantitative testing of opposing phylogenetic scenarios. Using optical surface scan data and geometric morphometric techniques, this study explores calvarial shape variation in the “Middle Pleistocene muddle”. The morphological variability between H. erectus on the one hand and H. sapiens/neanderthalensis on the other has long remained obscure: opposing views have attributed the known specimens to any of the three species and possibly one or two more. A large number of landmarks and semilandmarks was extracted from the braincase and the face, in order to quantify the calvarial shape differences among species and key fossils. The results are incompatible with the hypothesis that H. rhodesiensis is the exclusive ancestor of H. sapiens, and offer only weak support for an exclusively European ancestor of Neandertals."
Just in case, when I said Ethiopians I was joking. I do think in terms of generic Homo sapiens and East Africans in general may be a decent reference but there was a ";)" (wink) emote after the sentence indicating I was not really being serious.
ReplyDeleteBut I do think in ancient Homo sapiens as a tropical species, hence slender (even if probably not as exaggerated as some modern Ethiopians) is surely part of the concept.
"I thought the Inuit had the same body proportions as neanderthals".
No. They have some evolutionary convergence maybe but not the same proportions. They have modern human proportions, even if they may tend to be short and stocky.
Let's make a quick review of Neanderthal anatomical differences (under the head) with the help of Wikipedia:
* Considerably more robust, stronger build
* Long collar bones, wider shoulders
* Barrel-shaped rib cage
* Short, bowed shoulder blades
* Larger round finger tips
* Large kneecaps
* Thick, bowed shaft of the thigh bones, bowed femur
* Short shinbones and calf bones, longer torso and proportionally shorter legs
* Long, gracile pelvic pubis (superior pubic ramus)
I said femur before but that's wrong; it's actually the two bones of the lower leg: tibia (shinbone) and fibula (calf bone).
It is not the only major anatomical difference with H. sapiens but, together with their impressive robustness (and related energy demands), really makes the case for a somewhat different way of being, such as the one I illustrated with the fantasy dwarfs' example.
"Yes, maybe neanderthals couldn't run as fast as we can, after all".
Not a matter of speed (nor necessarily at running) as much as a matter of energy consumption per walked kilometer. Their movements were somewhat more costly than ours, everything else equal. Hence, on average they moved somewhat less, significantly so: enough to see smaller effective provisioning areas (in the same environments, vide Gamble 2001) and enough to have H. sapiens expanding in Asia earlier (very likely now) and faster.
It would also imply significantly lesser agility on average. This is not a matter of legs as much as a matter of robustness. Also, I am not sure, but it may also imply that they got tired sooner and they needed more food and oxygen (hence the large ribcage) for the same effort.
That was fine as long as our species did not begin competing: they were well fit but all things evolutionary are not absolute but relative. Still they seem to have kept advantage for some time in most of West Eurasia but eventually they could not keep it.
Maybe, as some have argued, ranged weapons were a reason for their demise. They could of course hurl weapons (though there's no evidence they did, unlike what happens with Cromagnons or Gravettian era humans) but, in any case, those weapons would imply total loss of their advantage in close combat, if there was ever a fight (and probably there were such conflicts now and then, deciding maybe who kept the territory).
...
"Yes, apparently these skeletal remains were associated with proto-Aurignacian tools, dated 40 Ka or older, but the skeletal remains turned out to be much younger than that".
ReplyDeleteThat doesn't make any sense. There must have been contamination of some sort in the bones: there's no logical way that Neolithic era people would end up buried with well dated proto-Aurignacian tools of all technologies. Sorry but I am thinking there's some error in this dating.
"I found an interesting study about neanderthal-modern human divergence. The authors studied skulls from various hominids, including neanderthals, erectus, rhodesiensis, sapiens, etc."
LINK
Well, I remain open to other possibilities, such as that of the "out of place" South Asian big-headed early Homo individual. But I'd need to see some clear evidence too.
PS - the more I look at Neanderthal and H. sapiens skulls (and other anatomical traits) the less possible a recent shared ancestry (such as those crazy dates of c. 300 Ka, just before the formation of both species) seems to me. They are so extremely different!
ReplyDeleteAnd modern "Caucasoid" H. sapiens skulls are maybe a bit different among each other and with archaic Sapiens but the differences are totally minor. I'm no expert but such big differences suggest many hundreds of millennia of divergent evolution. The only thing in common is big heads.
One possibility might be that the phylogenies going to H. antecessor/heidelbergensis and H. rhodesiensis are correct but that there was introgression of a gene for big heads, maybe original from India, which would be extremely adaptive (almost only highly adaptive genes can introgress, otherwise they are simply drifted out).
"It would also imply significantly lesser agility on average. This is not a matter of legs as much as a matter of robustness. Also, I am not sure, but it may also imply that they got tired sooner and they needed more food and oxygen (hence the large ribcage) for the same effort."
ReplyDeleteThat sounds realistic. I remember there was one gene involved in larger shoulders, which has a different version in all modern humans. That'd explain some anatomical differences for sure.
"Maybe, as some have argued, ranged weapons were a reason for their demise. They could of course hurl weapons (though there's no evidence they did, unlike what happens with Cromagnons or Gravettian era humans) but, in any case, those weapons would imply total loss of their advantage in close combat, if there was ever a fight (and probably there were such conflicts now and then, deciding maybe who kept the territory). "
I'm not too sure. I highly doubt there was any coexistence at all in western Europe. Maybe there's no reason at all to think they coexist for 10 millenia, just wrong dates.
"That doesn't make any sense. There must have been contamination of some sort in the bones: there's no logical way that Neolithic era people would end up buried with well dated proto-Aurignacian tools of all technologies. Sorry but I am thinking there's some error in this dating. "
I can't give my opinion as I couldn't read the study, but apparently the authors are quite convinced.
"PS - the more I look at Neanderthal and H. sapiens skulls (and other anatomical traits) the less possible a recent shared ancestry (such as those crazy dates of c. 300 Ka, just before the formation of both species) seems to me. They are so extremely different!"
They don't look extremely different to me. For example, I couldn't tell you before I knew, if this skeleton is from a "normal" human or not, but of course reconstructions can vary a lot:
http://www.boneclones.com/images/sc-019_web-lg.jpg
I find neanderthal skulls more similar to H. sapiens skulls than those of other archaic humans. Moreover, Middle Easterner neanderthals are more similar to H. sapiens than western neanderthals. I don't know why, maybe admixture or convergent evolution? Anyway, that's my opinion, I'm not an expert.
Europeans can seem broadly different from neanderthals, because most of them have pronounced chins, tiny noses, etc. But other modern humans, such as many African groups, are not so different from the average neandertal.
"One possibility might be that the phylogenies going to H. antecessor/heidelbergensis and H. rhodesiensis are correct but that there was introgression of a gene for big heads, maybe original from India, which would be extremely adaptive (almost only highly adaptive genes can introgress, otherwise they are simply drifted out)."
Introgression for big heads? This seems quite complicated... I think neanderthals aren't exclusively descended from just one lineage. That'd explain why they look so different sometimes, but of course, more studies are needed to confirm their (and our) position in the Homo family.
"I highly doubt there was any coexistence at all in western Europe".
ReplyDeleteAt no moment the issue of Neanderthal replacement is one limited to Western Europe: it happened in a large range from Altai to Gibraltar. Discussing it as something happening only in Europe (or worse: Western Europe) is totally missing the point.
"I can't give my opinion as I couldn't read the study, but apparently the authors are quite convinced".
I wish I knew what the authors think about the "misplacement" of the bones in a well dated Aurignacian context. Without explaining that there is no explanation.
As they say, "just because it's published in Nature, doesn't mean it's wrong". So I withhold my judgment.
"I find neanderthal skulls more similar to H. sapiens skulls than those of other archaic humans".
Because they are big only, in everything else (skull-wise) Neanderthals are very conservative and keep the patterns of earlier Homo, very specially the low vault (compensated by a larger head overall and more extreme dolicocephaly) but also the robust prominent jaw and other traits. The anomalous ones in this case are us.
There was a paper on this finding a few years ago but can't find the reference right now. The odd ones are us.
So IMO both Neandernthal and Sapiens evolved in parallel towards the only trait they share in comparison with H. erectus (senso lato): a bigger brain/head, which is a highly adaptive quantitative trait.
I haven't checked but from the neck down we don't seem to share much either in comparison with H. erectus/ergaster/etc.
"Moreover, Middle Easterner neanderthals are more similar to H. sapiens than western neanderthals- I don't know why, maybe admixture or convergent evolution?"
It may indicate admixture, what we know happened in our direction at small levels (and may have happened in the opposite direction at larger levels). Also some late European Neanderthals are more "like us", what again may indicate admixture.
"Introgression for big heads? This seems quite complicated..."
Not really: any introgressed gene should be highly adaptive and big heads, in principle conferring greater intelligence, is a highly adaptive trait. More so in humans, where it is central to our evolutionary path.
"I think neanderthals aren't exclusively descended from just one lineage".
They look that, at least based on genetics. Their diversity is low.
"At no moment the issue of Neanderthal replacement is one limited to Western Europe: it happened in a large range from Altai to Gibraltar. Discussing it as something happening only in Europe (or worse: Western Europe) is totally missing the point."
ReplyDeleteWhile it's quite clear they coexisted in the Middle East, there's not evidence at all they did in most Europe. For example, there's no evidence at all that neanderthals occupied the caves after modern humans, only before them (for example, the study at Cova Gran). There's no evidence at all of cultural and/or genetic exchange in Europe. There's no evidence that first (modern human) Europeans were more neanderthal-like than modern Europeans or modern Asians (see for example, the Crogmanon 1 skull). Most, if not all "hybrids" aren't widely accepted as such by most anthropologists.
"I wish I knew what the authors think about the "misplacement" of the bones in a well dated Aurignacian context. Without explaining that there is no explanation."
Mabye it's the same case as Saint-Césaire, being associated with Cahtelperronian, but now it seems there are other possible explanations, or alternatively, C14 dates are wrong.
"There was a paper on this finding a few years ago but can't find the reference right now. The odd ones are us."
yes, I remember this paper too. But not all "us". Europeans and Asians are specially odd, most Africans aren't.
"I haven't checked but from the neck down we don't seem to share much either in comparison with H. erectus/ergaster/etc."
That's very difficult to tell. In fact, neanderthals seem different, not only from H.sapiens, but also from erectus and ergaster.
I suppose that has something to do with their adaptations to cold environments, but I'm not sure.
"It may indicate admixture, what we know happened in our direction at small levels (and may have happened in the opposite direction at larger levels). Also some late European Neanderthals are more "like us", what again may indicate admixture."
Yes, that's possible, but apparently the analyzed neanderthals don't show any modern human admixture. Maybe in Europe all neanderthal and mixed H. sapiens died without leaving any descendant. The evidence for "hybrid" neandertals is quite scarce also in Europe, because for example, the chin of Saint Césaire 1 doesn't necessarily mean SC1 was mixed, because his/her chin is quite different from most modern European chins.
"Not really: any introgressed gene should be highly adaptive and big heads, in principle conferring greater intelligence, is a highly adaptive trait. More so in humans, where it is central to our evolutionary path."
Introgression means gene flow, right? That's quite logical giving the fact that there's there was more than one out-of-Africa expansion in the last 2 million of years. I don't believe a lot in introgression, because recently a microcephalin gene, involved in brain development, was also proposed to have entered in the human gene pool from neanderthals by introgression, but now we know that's false.
"They look that, at least based on genetics. Their diversity is low."
Their mtDNA diversity is very low, right. But also is the mtDNA diversity of modern Europeans compared with those of Africans, yet despite that, all non-Africans seem to have some archaic admixture, not present in Africans.
That could be the case for neandertals. They maybe suffered a population bottleneck 100.000 years ago, and many mtDNA lineages and diversity were lost.
We don't know yet if they're so homogeneous when looking at their nuclear DNAs. I wish we know something more about this soon.
"There's no evidence at all of cultural and/or genetic exchange in Europe".
ReplyDeleteWhile the term "evidence" is somewhat relative to the eye of the beholder, I'd say in Europe is where there is stronger evidence for cultural exchange, as Neanderthals may have adopted some phenomenons earlier only known to be made by H. sapiens, like mode 4 technologies or symbolic expression of Sapiens type (perforated ornaments, ochre...)
I think the difference in our perception is that you relate cultural exchange with sex and reproduction why I think it can be a quite asexual thing in fact.
Anyhow, some late Neanderthals have some "modern" features, maybe indicative of admixture in a single main direction (???).
"yes, I remember this paper too. But not all "us". Europeans and Asians are specially odd, most Africans aren't".
Was that part of the conclusions? I can agree with that up to some extent (mild prognathism, dolicocephaly are "conservative" traits) but these differences are quite mild among humans and for instance Khoisanids are not even really prognathous (while "Eurasian" Papuans are very much).
But there are elements like the high vault or the chin or the almost lack of protuberant browridge (probably related to the chin) that really places us apart in the Homo sp. morphologies.
"In fact, neanderthals seem different, not only from H.sapiens, but also from erectus and ergaster".
Fair enough.
"I suppose that has something to do with their adaptations to cold environments, but I'm not sure".
Maybe. They used fire and some type of clothes probably, so it's not like they needed so much that adaptation (depending where too) but I think their physiognomy is also adapted to combat. Not sure if it's true but I read once that Neanderthals might have been able to fight barehanded with a cave lion, a la Sanson/Hercules. More reliable is maybe the idea that a typical Neanderthal woman would easily beat a strong Sapiens man in a wrestling duel (skill apart). So maybe their adaptation is also related to hunting (without ranged weapons).
Or maybe there's a lot of randomness. I'm not necessarily into thinking every single trait is an adaptation: some are clearly so, others more diffusely and others are just random stuff.
"... for example, the chin of Saint Césaire 1 doesn't necessarily mean SC1 was mixed, because his/her chin is quite different from most modern European chins".
Again, fair enough.
"Introgression means gene flow, right?"
In a very specific manner: unlike in simple admixture, in introgression most genes don't overcome the barrier because the flow is very low (typically mediated by a tiny hybrid population), so they are "drifted out" by the mainstream gene pools of each population (species, subspecies, whatever) and those who survive such draconian filters do because they are actively selected for, because the gene(s) in question is/are highly adaptive. That way an adaptive gene can migrate from one population to another, while the bulk of the, less useful, genetics does not.
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ReplyDelete"I don't believe a lot in introgression, because recently a microcephalin gene, involved in brain development, was also proposed to have entered in the human gene pool from neanderthals by introgression, but now we know that's false".
Well, the microcephalin story looked really bad from the beginning: it was not clear it was adaptive at all (speculation) and the proportions really suggested the typical pan-Eurasian founder effect (like 70% in Eurasians and 30% in Africans, only the three standard HapMap populations were screened). If it was so extremely adaptive (and not knowing yet the case of the admixture upon the arrival to Asia) we should have expected more homogeneous apportions probably, even in Africa. Of course there was no evidence of anything but as there are many quasi-nazis in this field of Anthropology (specially in the amateur arenas), the story soon became popular and a motive for implicit racism against Africans.
It smelled very bad, specially as the ones defending it were, as would be expected, those who love to emphasize how genetic differences resemble classical races and give credence to IQ pseudoscience also along racist (and often also sexist) lines.
Fortunately it was soon proven they were wrong. Not that any of them apologized anyhow.
But that does not deny introgression as such, which has been seen on occasion in animal and plant examples, which are ideologically neutral.
"Their mtDNA diversity is very low, right. But also is the mtDNA diversity of modern Europeans compared with those of Africans"...
Fair enough. I also mentioned back then that comparing Neanderthals, who never adventured beyond Western Eurasia and are extinct since long ago with the modern humankind of 7 billion people is not really fair. However Europe is large enough to have allowed Neanderthals to evolve some level of diversity, much as Sapiens did in Africa (where most of modern human diversity still lays).
But I may be wrong in this last part because Africa is much larger than Europe. And this makes me think that maybe a reason for the demise of Neanderthals could be that they could never become as diverse as Sapiens because their homeland was much smaller.
A lot of adaptive value is in diversity rather than in specific alleles. Often having several alleles to "choose", depending on circumstances, can guarantee survival for a population, while low diversity can be a huge problem, as all breeders know: the best adapted animals for this or that purpose can suffer in other aspects, dynamic equilibrium is called and I'd say it's pretty much central to evolution and adaptation. The best stallion or the most productive milk cow can succumb to an unexpected illness or whatever other random unpredictable threat, only with enough diversity can this be reasonably prevented.
"While the term "evidence" is somewhat relative to the eye of the beholder, I'd say in Europe is where there is stronger evidence for cultural exchange, as Neanderthals may have adopted some phenomenons earlier only known to be made by H. sapiens, like mode 4 technologies or symbolic expression of Sapiens type (perforated ornaments, ochre...) "
ReplyDelete"Anyhow, some late Neanderthals have some "modern" features, maybe indicative of admixture in a single main direction (???)."
Admixture in only one direction has not too many sense to me. Maybe gene flow was mainly from modern humans to neandertals, but definitely not exclusively. After all, how many late neandertals in Europe have been proposed to have some modern human ancestry? I remember some specimens from Vindija, but after being redated and their mtDNAs analyzed, this possibility has been gone.
Saint-Césaire? Not at all. First, anthropologists used to think it was a mixed male, because it has gracile features, but now it's quite clear it's a female. About the "modern" features, none is conclusive for admixture: the chin is not an exclusive trait of H. sapiens, and it can vary a lot.
Neanderthals from Sima de las Palomas show some modern features, but we only have their lower jaws. The most recent ones have been dated to nearly 40.000 years. While admixture with new incomers is the most likely explanation, others, like an higher neandertal diversity or convergent evolution can't be excluded.
Were modern humans already living in the iberian peninsula, by these dates? Maybe. Maybe not.
I don't more case of admixed european neandertals.
It seems that the last neanderthals continued to produce Mousterian industry, while no one knows who invented Chatelperronian. Neanderthals have been proposed, but now it seems that the evidence is vanishing.
"In a very specific manner: unlike in simple admixture, in introgression most genes don't overcome the barrier because the flow is very low (typically mediated by a tiny hybrid population), so they are "drifted out" by the mainstream gene pools of each population (species, subspecies, whatever) and those who survive such draconian filters do because they are actively selected for, because the gene(s) in question is/are highly adaptive. That way an adaptive gene can migrate from one population to another, while the bulk of the, less useful, genetics does not. "
I don't know but if neanderthals were able to admix with modern humans less than 100.000 years ago, why wouldn't they be able to admix with other archaic huamns, perhaps more akin to them, 500.000 years ago? I don't see why this flow had to be so low.
"Well, the microcephalin story looked really bad from the beginning: it was not clear it was adaptive at all (speculation) and the proportions really suggested the typical pan-Eurasian founder effect (like 70% in Eurasians and 30% in Africans, only the three standard HapMap populations were screened). If it was so extremely adaptive (and not knowing yet the case of the admixture upon the arrival to Asia) we should have expected more homogeneous apportions probably, even in Africa. Of course there was no evidence of anything but as there are many quasi-nazis in this field of Anthropology (specially in the amateur arenas), the story soon became popular and a motive for implicit racism against Africans."
ReplyDeleteMoreover, this gene is broadly distributed in Africa, it's not "absent" like many claimed. I read it has some correlation with speech (tonal or not tonal languages):
http://news.sciencemag.org/sciencenow/2007/05/29-01.html
As expected, the ancestral, not derived allele for microchephalin has been discovered in neandertals. Dienekes commented it on his blog, and claiming it was an evidence for "his" theory explaining the neandertal genome interpretations: ancient poplation structure in Africa: maybe the line leading to Europeans already carried this gene about a million of years ago, while the "black" line didn't.
I'm also highly sketpical with the dates. Another gene called HAT2 I think also was purposed to have a neandertal origin. The two versions of the gene, HAT1 and HAT2 split from each other more than 3.000.000 years ago, according to this study. Moreover, HAT2 is exclusively found in europeans.
But a recent study concluded that the dates are wrong: the HAT2 version is less than 60.000 years old!
"But I may be wrong in this last part because Africa is much larger than Europe. And this makes me think that maybe a reason for the demise of Neanderthals could be that they could never become as diverse as Sapiens because their homeland was much smaller."
Yes, maybe, but it doesn't seem that modern Europeans have to gone extinct. It seems that neanderthals going through a bad patch in the last 100.000 years of their existence.
"And this makes me think that maybe a reason for the demise of Neanderthals could be that they could never become as diverse as Sapiens because their homeland was much smaller."
Well, according to Trinkaus, it seems they also lived in East Asia, although there's no evidence. But they lived in Central Asia, because a specimen was found there and his mtDNA fit well with those of other neandertals.
"A lot of adaptive value is in diversity rather than in specific alleles. Often having several alleles to "choose", depending on circumstances, can guarantee survival for a population, while low diversity can be a huge problem, as all breeders know: the best adapted animals for this or that purpose can suffer in other aspects, dynamic equilibrium is called and I'd say it's pretty much central to evolution and adaptation. The best stallion or the most productive milk cow can succumb to an unexpected illness or whatever other random unpredictable threat, only with enough diversity can this be reasonably prevented."
I agree.
"Admixture in only one direction has not too many sense to me. Maybe gene flow was mainly from modern humans to neandertals, but definitely not exclusively. After all, how many late neandertals in Europe have been proposed to have some modern human ancestry? I remember some specimens from Vindija, but after being redated and their mtDNAs analyzed, this possibility has been gone. Saint-Césaire? Not at all".
ReplyDeleteFair enough. I acknowledge your superiority of knowledge in this matter and what you say makes sense.
"Neanderthals from Sima de las Palomas show some modern features, but we only have their lower jaws".
Isn't that the site of the famous perforated shell with ochre? That would be interesting if correct.
"It seems that the last neanderthals continued to produce Mousterian industry, while no one knows who invented Chatelperronian. Neanderthals have been proposed, but now it seems that the evidence is vanishing".
It's being questioned. The debate has been re-opened but nothing is clear yet (and may not be ever). Also we have the Uluzzian, with teeth believed to be Neanderthal and UP industry with blades, bone points and ornaments.
The specifics of the transition are not fully clear yet.
I agree that unidirectional admixture doesn't seem to make much sense but it could be the case if this admixture only happened with the first Sapiens "avant-guards", like maybe proto-Aurignacian. No idea, honestly.
"why wouldn't they be able to admix with other archaic huamns, perhaps more akin to them, 500.000 years ago?"
It is generally believed that H. sapiens and H. neanderthalensis are both descendants from African H. ergaster, which is not exactly the same as Asian H. erectus. So Neanderthals would not be closer to the first inhabitants of Eurasia (in the Homo genus) than to us in any case.
"I read [microcephalin] has some correlation with speech (tonal or not tonal languages)".
That's most interesting and I know someone who will love to read about this. :)
"Yes, maybe, but it doesn't seem that modern Europeans have to gone extinct".
It's not comparable. Specially not after Columbus, de Gama and Elkano. But not in any case because the relative isolation of the populations has no possible comparison, nor has the technological level, nor anything I know of. But certainly Europeans and all Eurasians have some lesser genetic disadvantage in comparison to Africans for the mere reason that Africans are much more diverse (can't find the reference right now but there was at least one paper on that).
"Fair enough. I acknowledge your superiority of knowledge in this matter and what you say makes sense."
ReplyDeleteSuperiority? Not at all... I get lost easily with so different opinions, dates being changed, etc.
I think you have a much clear opinion on this issue.
"Isn't that the site of the famous perforated shell with ochre? That would be interesting if correct."
No, that's not correct :) These shells were found at Cueva de los Aviones, which is also in Murcia, but it's a different one. Moreover, these shells were dated at 50 K, while the Palomas neandertals are more or less 40 K, that is, 10.000 years younger.
"It is generally believed that H. sapiens and H. neanderthalensis are both descendants from African H. ergaster, which is not exactly the same as Asian H. erectus. So Neanderthals would not be closer to the first inhabitants of Eurasia (in the Homo genus) than to us in any case. "
I didn't mean this exactly. I was saying that if the gene for "big heads" appeared first in the line leading to H. sapiens some 500.000 years ago, when they already diverged from neanderthals, that any gene flow (inbreeding) would have been easier between the two lines.
"But certainly Europeans and all Eurasians have some lesser genetic disadvantage in comparison to Africans for the mere reason that Africans are much more diverse (can't find the reference right now but there was at least one paper on that)."
OK, I got the point.
"I think you have a much clear opinion on this issue".
ReplyDeleteI have probably more clear ideas re. genetic and Sapiens prehistory. But I'm no Neanderthal expert: they are a side issue for me.
"No, that's not correct :) These shells were found at Cueva de los Aviones, which is also in Murcia, but it's a different one. Moreover, these shells were dated at 50 K, while the Palomas neandertals are more or less 40 K, that is, 10.000 years younger".
Ok, thanks. Guess I was getting confused by the bird names of the caves and both being in Murcia.
"I was saying that if the gene for "big heads" appeared first in the line leading to H. sapiens some 500.000 years ago, when they already diverged from neanderthals, that any gene flow (inbreeding) would have been easier between the two lines".
I do not know even if it was a single "gene", I mean: if the same genes are involved or what. My speculation is based on the Narmada hominin (Hathnora and not Patpara, as I have said somewhere), which is (or at least may be) the first "big head" known and is neither Neander nor Sapiens (it seems: lots of debate it has raised). My conjecture is about a Homo sp. (ergaster??) Indian branch that would have then introgressed those genes into Europe and Africa.
Just speculation so far. Hathnora is dated to 300-200 Ka. and is not clear what it is. It has some 1150-1420 cc. of brain space what is in the modern range (a bit low but it's a "pygmy" individual, so it's ok) rather than in that of H. ergaster/erectus/heidelbergensis/rhodesiensis.
"Just speculation so far. Hathnora is dated to 300-200 Ka. and is not clear what it is. It has some 1150-1420 cc. of brain space what is in the modern range"
ReplyDeleteVery interesting! A DNA test would clarify it. If H. sapiens was already in India by these dates that'd be... unexpected. We'd need to change or revise all our current theories.
It'd be ideal but aDNA is not always recoverable... and there's always the issue of contamination as well.
ReplyDelete