December 01, 2010

Paleoamerican Morphology in the Context of European and East Asian Late Pleistocene Variation (Hubbe et al. 2010)

I will write more on this paper later, as it is very important, and not just about the origins of Native Americans.

American Journal of Physical Anthropology DOI: 10.1002/ajpa.21425

Paleoamerican morphology in the context of European and East Asian late Pleistocene variation: Implications for human dispersion into the new world

Mark Hubbe, Katerina Harvati, Walter Neves

Abstract

Early American crania show a different morphological pattern from the one shared by late Native Americans. Although the origin of the diachronic morphological diversity seen on the continents is still debated, the distinct morphology of early Americans is well documented and widely dispersed. This morphology has been described extensively for South America, where larger samples are available. Here we test the hypotheses that the morphology of Early Americans results from retention of the morphological pattern of Late Pleistocene modern humans and that the occupation of the New World precedes the morphological differentiation that gave rise to recent Eurasian and American morphology. We compare Early American samples with European Upper Paleolithic skulls, the East Asian Zhoukoudian Upper Cave specimens and a series of 20 modern human reference crania. Canonical Analysis and Minimum Spanning Tree were used to assess the morphological affinities among the series, while Mantel and Dow-Cheverud tests based on Mahalanobis Squared Distances were used to test different evolutionary scenarios. Our results show strong morphological affinities among the early series irrespective of geographical origin, which together with the matrix analyses results favor the scenario of a late morphological differentiation of modern humans. We conclude that the geographic differentiation of modern human morphology is a late phenomenon that occurred after the initial settlement of the Americas.

Link

13 comments:

pconroy said...

Very interesting!

This of course could mean that a common population spread the characteristic East Asian/Amerindian feature set - like possibly based in Beringia, or else in North Easr Asia, spreading to North America?!

formerjerseyboy said...

From an amateur's point of view, this means then that the roots of the Amerindian population pre-date the Eurasian split into Caucasian and Mongoloid phenotypes, and therefore needs to be classified independtly of either. At the risk of reading too much into this (and other) recent research, would it be accurate to say that Amerindian populations are perhaps closer phenotypically (than Caucasian/Mongoloid populations)to the original modern humans that first left Africa?

Andrew Oh-Willeke said...

The data from the crania are in accord with the apparently quite young date for other differences in appearance that are now considered central to the intuitive sense of racial classification. Modern hair color, hair type, eye color, epicantic folds, and skin color differentiation are all widely viewed as arising thousands of years post-LGM. East Asians started to look like modern East Asians, and Europeans started to look like modern Europeans sometime ca. 16,000-10,000 years ago, give or take.

Incidentally, the pigmentation genes that give Northern Europeans their light colored appearance are different from genes that apparently gave Neanderthals their appearance -- Neaderthals would have had much lighter pigmentation than Cro-Magnons at the time of first content, but the paler European pigmentation came tens of thousands of years after this period of overlap had ended as a result of convergent evolution, from as a result of hybridization.

"would it be accurate to say that Amerindian populations are perhaps closer phenotypically (than Caucasian/Mongoloid populations)to the original modern humans that first left Africa?"

I don't think so. Paleo-Indians and modern Amerindian morphology were very different, probably to at least the same extent that we see differences between Paleo-Europeans and Paleo-Asians (with all three Paleo populations being quite similar) and modern Europeans and Asians respectively.

The most well known image of what a Paleo-Indian may have looked like is the reconstruction attempt done of Kennewick man.

Andrew Oh-Willeke said...

Another reconstruction of a Paleo-Indian face which is not as famous, but complements the masculine picture from Kennewick man is Luzia woman.

Dienekes said...

Europeans started to look like modern Europeans sometime ca. 16,000-10,000 years ago, give or take.

Not true, as the authors find a clear link between Upper paleolithic Europeans and the Norse population. Also, since they lack West Asian UP samples, they cannot conclude that populations were globally undifferentiated until recently.

What happened in the case of Europe is that the modern morphology is largely the result of Neolithic and post-Neolithic arrival of people from outside Europe + natural selection. But, in the fringes of the continent the Upper Paleolithic population was absorbed in greater numbers and thus the clear link emerges.

Charlie said...

Dienekes wrote:

"Not true, as the authors find a clear link between Upper paleolithic Europeans and the Norse population."


Charlie Bass replies:

What you left out Dienekes is that according to the paper itself, the European Upper Paleolithic sample itself is closer to the Zulu sample than to the Norse sample so which one did the EUP look more like, a Zulu or a Norse?

Dienekes said...

If by "closer" you mean 11.7 (Zulu) vs. 11.99 (Norse) and 12.11 (Zalavar), then, yeah, it's closer.

And, the point was that UP Europeans did not start to look like modern Europeans 16,000 years ago, the process had already started long before, and by the time of these Early Upper Paleolithic specimens they were already halfway there.

Charlie said...

Dienekes wrote:

"And, the point was that UP Europeans did not start to look like modern Europeans 16,000 years ago, the process had already started long before, and by the time of these Early Upper Paleolithic specimens they were already halfway there."

Charlie Replies:

How could they already be halfway looking "European" already when they looked more like Zulus according to the analysis of the study itself? Zulus don't look like modern Europeans so your statement is not in line with what the study stated. Also, the EUP sample wasn't far from the Teita sample which you left out(12.28). What we see is that the EUP samples shows equally and slightly stronger relationships to both modern sub-Saharan and European samples so the results can't be solely interpreted that the EUP sample was already "halfway" European looking.


Dienekes wrote:

" Also, since they lack West Asian UP samples, they cannot conclude that populations were globally undifferentiated until recently."


This is incorrect, included among the EUP samples used was the OhaloII samples from the Rift valley of Israel.

Dienekes said...

so the results can't be solely interpreted that the EUP sample was already "halfway" European looking.

Well, the Zulu are 12.09 to recent Zalavar and 11.7 to Upper Paleolithic. Are you going to say that Zalavar look like "Africans" too?

Charlie said...

Dienekes said:

"Well, the Zulu are 12.09 to recent Zalavar and 11.7 to Upper Paleolithic. Are you going to say that Zalavar look like "Africans" too?"

Charlie replies:

I'm simply making the case that one can equally and more convincingly say that European Upper Paleolithics were halfway already looking like Zulus also. Most modern Europeans don't look "Norse" anyways.

Dienekes said...

I will soon unleash the power of MCLUST on Cro-Magnon I and a few other Paleolithic skulls, and we'll see its verdict.

formerjerseyboy said...

Very interesting line of discussion. However, isn't it true that the genetic closeness of an European UP population with a Zulu genetic profile has very little meaning when the respective physical appearances are concerned? In other words, is there is nothing stopping a person with very little genetic distance from a typical "Zulu" profile from actually having very light colored skin, even blond hair and blue eyes? All it takes is just a couple of genes to be different ...

terryt said...

"I will soon unleash the power of MCLUST on Cro-Magnon I and a few other Paleolithic skulls, and we'll see its verdict".

That will be extremely interesting.