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I don't think I've seen this study posted here. If it has please excuse the redundancy.
quote:Human cranial anatomy and the differential preservation of population history and climate signatures.
Harvati K, Weaver TD.
Department of Human Evolution, Max Planck Institute for Evolutionary Anthropology, Leipzig, Germany. harvati@eva.mpg.de
Cranial morphology is widely used to reconstruct evolutionary relationships, but its reliability in reflecting phylogeny and population history has been questioned. Some cranial regions, particularly the face and neurocranium, are believed to be influenced by the environment and prone to convergence. Others, such as the temporal bone, are thought to reflect more accurately phylogenetic relationships. Direct testing of these hypotheses was not possible until the advent of large genetic data sets. The few relevant studies in human populations have had intriguing but possibly conflicting results, probably partly due to methodological differences and to the small numbers of populations used. Here we use three-dimensional (3D) geometric morphometrics methods to test explicitly the ability of cranial shape, size, and relative position/orientation of cranial regions to track population history and climate. Morphological distances among 13 recent human populations were calculated from four 3D landmark data sets, respectively reflecting facial, neurocranial, and temporal bone shape; shape and relative position; overall cranial shape; and centroid sizes. These distances were compared to neutral genetic and climatic distances among the same, or closely matched, populations. Results indicate that neurocranial and temporal bone shape track neutral genetic distances, while facial shape reflects climate; centroid size shows a weak association with climatic variables; and relative position/orientation of cranial regions does not appear correlated with any of these factors. Because different cranial regions preserve population history and climate signatures differentially, caution is suggested when using cranial anatomy for phylogenetic reconstruction. Copyright (c) 2006 Wiley-Liss, Inc.
posted
^ I think this was posted here before since it looks familiar, but it is likely buried somewhere in the archives. But it pretty much supports what has been said in this forum for years.
Posts: 26311 | From: Atlanta, Georgia, USA | Registered: Feb 2005
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posted
^ Why is it a good find. It rather obvious isn't it? If you are going to use phenotype to group people then what you are doing is simply grouping people by climate. If you want to know if people are related and their origins then you need genetics.
I think this is all a no brainer! Climate has a direct impact on diet. Diet is what makes us who were are. Its an old saying - you are what you eat!
-------------------- Across the sea of time, there can only be one of you. Make you the best one you can be. Posts: 4028 | From: NW USA | Registered: May 2005
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quote: The Linear Measurements of the Neurocranium Are Better Indicators of Population Differences than Those of the Facial Skeleton: A Comparative Study of 1961 Skulls Gábor Holló, László Szathmáry, Antónia Marcsik, and Zoltán Barta Abstract The aim of the study was to individualize potential differences between two cranial regions in differentiating human populations. The neurocranium and the facial skeleton were compared to each other. Skulls from the Great Hungarian Plain were examined. They are dated back to the 1st – 11th centuries, a long space of time that encompasses seven archaeological periods. We analyzed six neurocranial and seven facial measurements. The reduction of the number of variables was carried out by Principal Components Analysis. Linear mixed-effects models (LMM) were fit to the principal components of each archaeological period, and then the models were compared by multiple pairwise tests. The neurocranium showed significant differences in seven cases between non-subsequent periods, and, in one case, between two subsequent populations. In the case of the facial skeleton, no significant results were found. Our results, which are also compared to previous craniofacial heritability estimates, suggest that the neurocranium is a more conservative region, and population differences can be pointed out better by the neurocranium than by the facial skeleton.
Posts: 1038 | From: Franklin Park, NJ | Registered: Aug 2005
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quote:^ Why is it a good find. It rather obvious isn't it? If you are going to use phenotype to group people then what you are doing is simply grouping people by climate. If you want to know if people are related and their origins then you need genetics.
I think this is all a no brainer! Climate has a direct impact on diet. Diet is what makes us who were are. Its an old saying - you are what you eat!
That's not what the study is addressing.
Posts: 1038 | From: Franklin Park, NJ | Registered: Aug 2005
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quote:Our results, which are also compared to previous craniofacial heritability estimates, suggest that the neurocranium is a more conservative region, and population differences can be pointed out better by the neurocranium than by the facial skeleton.
What this means, I'm hoping The Explorer or Mindovermatter can correct me if I'm wrong, is the dolichocephalic neurocrania generally found among African blacks, including Ancient Egyptians, is more of an indicator of relatedness than the cranio-facial similariities between some North East Africans and Europeans.
Posts: 1038 | From: Franklin Park, NJ | Registered: Aug 2005
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I missed this thread. Err, look at Osirion.
quote:Originally posted by Apocalypse:
quote:Our results, which are also compared to previous craniofacial heritability estimates, suggest that the neurocranium is a more conservative region, and population differences can be pointed out better by the neurocranium than by the facial skeleton.
What this means, I'm hoping The Explorer or Mindovermatter can correct me if I'm wrong, is the dolichocephalic neurocrania generally found among African blacks, including Ancient Egyptians, is more of an indicator of relatedness than the cranio-facial similariities between some North East Africans and Europeans.
Yes, that is correct. Neurocrania form is more likely retained amongst populations that developed within the same corridor. In other words, the various East Africoid traits are merely local variability within the great African continent.
On the other hand, Europeans, being, relatively, isolated, have developed a neuro-cranium that has diverged from the African counterpart. However, I would not take this too religious.
Those within Africa, being the mother population of Europeans, feature the underived markers that produce these traits. That means that such traits could developed within Africa. However, these type of papers will likely use the more traditional XY analysis.
I think if European samples were studied themselves, I'd reckon we'd see indication of some isolation. That is because "Europeans" were isolated from each other, due to glaciation. The evolutionary history of these peoples would be more understood if we have well controlled studies on these matters.
PS: Observe the pre-historic neolithic European populations.
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^Thanks for the feedback Bob_01. I have a poor grasp of this stuff relative to you guys but my thinking is that along with tropical limb ratios neuro-crania (dolichocephalic vs mesocephalic and brachycephalic) may be another indicator of the relatedness of Africans including Egyptians. (An exception I came across which speaks to your point above is that northern Europeans are also dolichocephalic). More importantly the study discounts the importance of cranio-facial differences.
Posts: 1038 | From: Franklin Park, NJ | Registered: Aug 2005
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We talk about limb ratio this and limb ratio that. Cold adapted this and tropical adapted that.
Where do the East Asians(Chinese) fit in? They have stubby limbs. Does that make them cold adapted?
Watched a special over the weekend about ancient China.
Seems like the Great Wall was built to keep the Northern Barbarians out. What is it with the "northerners". All ancient civilization think they were Barbarians?
Posts: 12143 | From: When you have eliminated the impossible, whatever remains, however improbable | Registered: Jun 2007
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quote:We talk about limb ratio this and limb ratio that. Cold adapted this and tropical adapted that.
Where do the East Asians(Chinese) fit in? They have stubby limbs. Does that make them cold adapted?
Watched a special over the weekend about ancient China.
Seems like the Great Wall was built to keep the Northern Barbarians out. What is it with the "northerners". All ancient civilization think they were Barbarians?
Good question. I'm not sure about the limb ratio of East Asians but I'd guess it would not fit a tropical pattern. I do know that their neuro-crania is typically brachycephalic.
And yes from what I remember the Great Wall was built to keep out the mongols.
Posts: 1038 | From: Franklin Park, NJ | Registered: Aug 2005
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What applies to European should apply to the East Asians.
They have light skin and short limbs. So are they cold adpated?
Assuming, whats her name, is correct the agricultural revolution triggered the change in skin color. This should apply to the Chinese also.
What about the UV distribution on that part of the world?
Where is Explorer. . . . . blog us buddy!! Posts: 12143 | From: When you have eliminated the impossible, whatever remains, however improbable | Registered: Jun 2007
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posted
If you're inclined to post "studies" to substantiate a claim or ideology you posses, please ensure that the study itself, doesn't summarize it's findings with the following quote:
quote:Because different cranial regions preserve population history and climate signatures differentially, caution is suggested when using cranial anatomy for phylogenetic reconstruction. Copyright (c) 2006 Wiley-Liss, Inc.
and begin with this:
quote:..its reliability in reflecting phylogeny and population history has been questioned.
It lets you know that everything in the center is nothing more than a 'working hypothesis', in essence 'inconclusive'.
Posts: 747 | From: Atlanta, GA USA | Registered: May 2004
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quote:If you're inclined to post "studies" to substantiate a claim or ideology you posses
I am so inclined.
quote:please ensure that the study itself, doesn't summarize it's findings with the following quote:
quote: -------------------------------------------------------------------------------- Because different cranial regions preserve population history and climate signatures differentially, caution is suggested when using cranial anatomy for phylogenetic reconstruction. Copyright (c) 2006 Wiley-Liss, Inc.
Okay teacher. I'll review the summary of any future "study" I post here to make sure it does not contain the words you ruled out above.
Posts: 1038 | From: Franklin Park, NJ | Registered: Aug 2005
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