PNAS, Proceedings of the National Academy of Science, has published a paper concerning the teeth of a fossil known as Lagar Velho I or the LV 1 in scientific parlance. It seems, from a superficial glance at the paper, which was written by several experts who did the study, and who have long had ties with the ongoing research on the Lagar Velho fossil, that there were things about the child's teeth that seem more like that of some Neandertals, than of "modern" humans.
To give anyone reading this a background, the Lagar Vellho fossil was discovered in, IIRC, 1995. It was thought at first that the child, who was apparently about four or five years old when it died, was an example of early "modern" burial culture, and that was about it. Then Erik Trinkaus, a Neandertal expert and one of the authors of the present paper, took a closer look. He said he found that the child's skeletal proportions suggested a mixture of early "modern" and Neandertal traits. João Zilhão, one of the original discoverers, and also an author of the paper, declared at the time, and has been declaring ever since, that Neandertals "took their last stand" so to speak, on the Iberian Peninsula, and the early "modern" population was a "mixed" one. Needless to say, these assertions have been disputed, just as almost everything concerning Neandertals has been.
Whether or not one believes these claims, it is certainly true that early "modern" humans, e.g. Homo(sapiens)sapiens were more "robust", and in some ways, more like Neandertals, than later ones. This, as Razib of Gene Expression points out, is probably due in part, at least, to the introduction of agriculture in the so-called Neolithic period. You just don't need as much muscle and bone bulk to grow crops, as you do to go out and hunt or gather your own meals, so it's no wonder people switched to agriculture! By that time, of course, there weren't any Neandertals, and, when people started switching to agriculture, there probably weren't that many "modern" foragers(e.g., what have previously been called "hunter-gatherers"). Agriculturalist populations were larger, and probably "swamped" the hunter-gatherers.
Which is food for thought. At the time they existed, Neandertal populations were even smaller than later "forager" populations, and little groups of them apparently hung on is relative semi-isolation on the Iberian Peninsula rather late. "Modern" populations eventually filtered their way into the peninsula, but there may not have been very many of them, either, at the time. Which may account for the "mixed" population, if there was a "mixed" population(people have disagreed about this, too). In any case, assuming "moderns" and Neandertals "mixed" in the Iberian Peninsula or anywhere else(and they might have, in some places, at various times), there weren't very many of the "mixed" populations, either. Which would make them easy to "swamp" genetically, even if more "gracile" people didn't originally have some genetic advantage. In any case, as the PNAS article seems to be suggesting, the "modern European origins" story is rather more complex than some people like to believe.
Anne G
5 comments:
"the 'modern European origins' story is rather more complex than some people like to believe".
I've been arguing exactly that with Maju at his leherensuge blog. I think people always look for simple answers to complex questions. That's why religion has such a hold.
"assuming 'moderns' and Neandertals 'mixed' in the Iberian Peninsula or anywhere else(and they might have, in some places, at various times)"
I think the obvious place for them to have mixed (and a region completely overlooked) is on the Iranian Plateau. That would mean that the population who moved into India was a hybrid population, as would have been any that might have moved through Central Asia into the Far East, and then down to Australia.
terryt:
There are any number of places they could have "mixed" at various times. I never thought of the Iranian Plateau, though Shanidar Cave is more or less in that area. However, another possibility is the Eastern Mediterranean(e.g. Israel, Syria, etc.) where both Neandertals and "moderns" are known to have existed or coexisted. But perhaps that's another story.
Anne G
Except that the general consensus seems to be that the the two kept very much to their own company in the Levant. Of course lack of specimens demonstrating mixed ancestry is not evidence of their absence, or something like that.
Maybe it's true each group "ketp to their own company" in the Eastern Mediterranean. It largely depends on who you read, and how they interpret what evidence there is. My own view is that the populations fluctuated, depending on what glaciers did farther north. When things got really nasty in the north, some Neandertals drifted into the area, and when things warmed up again, the "moderns" tended to be more dominant. This could have happened over thousands of years, and not very fast. However, when one population was dominant, didn't necessarily mean the other population was completely absent, and the "always" kept apart. Some places and fossils, like(I think) Qafzeh 9, aren't entirely "modern" looking, and some Neandertals(e.g. at Tabun, were there awfully early, perhaps some 130,000 years ago.
Anne G
"When things got really nasty in the north, some Neandertals drifted into the area, and when things warmed up again, the 'moderns' tended to be more dominant".
I'm sure that is correct. I'm also sure they were far from being separate species. Subspecies perhaps, but subspecies, by definition, are capable of forming fertile hybrids. If in fact Neanderthals and moderns failed to interbreed it was for some other reason than genetic incompatability. Tribalism? Racism?
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