June 18, 2011

Stature and robusticity during the Neolithic transition: population replacement, not necessarily declining health

First of all, I would like to say that I don't doubt that the Neolithic transition led to a deterioration in health. Contrary to the authors of this paper who suggest that this is "counterintuitive", it would be unexpected if it didn't happen: man lived as a hunter-gatherer for millions of years, and all of the sudden converted to a new lifestyle for which he was not well-suited; it would be surprising if his health did not deteriorate. A good analogy is what is happening right now in much of the world as it undergoes a transition from farming to modern technological life: rise in obesity and its attendant problems, various mental illnesses, etc.

Second, there is a serious flaw with the general thesis that reduction in stature and robusticity was the product of the agricultural transition, as this requires the additional hypothesis that foragers and their succeeding farmers in the same region were the same people. What we are slowly beginning to learn is that they were, in fact, not, and that there have been massive population replacements, beginning with the Neolithic in much of the world.

So, for example, the fact that Neolithic Europeans were shorter than so-called Cro-Magnons is not, so much caused by agriculture, but by the fact that Neolithic Europeans were derived from a people that lived in a hotter climate and were thus smaller-bodied in accordance with Bergmann's Rule. This is consistent, also with the observation (found in the paper) of the Portuguese data not following the general pattern, as Portugal's pre-farming population was not as tall as pre-farmers in more northern latitudes.

So, while it is probably true (and expected) that the agricultural transition was a stressful event for the human species, caution must be exercised when interpreting the pattern of change.

Econ Hum Biol. 2011 Jul;9(3):284-301. Epub 2011 Apr 1.

Stature and robusticity during the agricultural transition: Evidence from the bioarchaeological record.

Mummert A, Esche E, Robinson J, Armelagos GJ.

Abstract
The population explosion that followed the Neolithic revolution was initially explained by improved health experiences for agriculturalists. However, empirical studies of societies shifting subsistence from foraging to primary food production have found evidence for deteriorating health from an increase in infectious and dental disease and a rise in nutritional deficiencies. In Paleopathology at the Origins of Agriculture (Cohen and Armelagos, 1984), this trend towards declining health was observed for 19 of 21 societies undergoing the agricultural transformation. The counterintuitive increase in nutritional diseases resulted from seasonal hunger, reliance on single crops deficient in essential nutrients, crop blights, social inequalities, and trade. In this study, we examined the evidence of stature reduction in studies since 1984 to evaluate if the trend towards decreased health after agricultural transitions remains. The trend towards a decrease in adult height and a general reduction of overall health during times of subsistence change remains valid, with the majority of studies finding stature to decline as the reliance on agriculture increased. The impact of agriculture, accompanied by increasing population density and a rise in infectious disease, was observed to decrease stature in populations from across the entire globe and regardless of the temporal period during which agriculture was adopted, including Europe, Africa, the Middle East, Asia, South America, and North America.

Link

20 comments:

Gnarlodious said...

A likely factor is that early agricultural adopters knew nothing of the hazards and fell victims to their own innovation. Agriculture is an incubator for disease evolution, and they may have been subject to periodic plagues, pestilence and blights. Even today we see cross-species diseases as a result of close living in unsanitary conditions, sometimes with humans living with animals. Germs that are forced to exist in conditions nature would never allow gave them an opportunistic chance to mutate into their new habitat.

So it is safe to assume this was the case ever since the invention of agriculture. Especially at the beginning, when germs expanded into new agricultural habitat.

Annie Mouse said...

The case for population replacement is very very far from proven and it cynical to state it as fact.

My guess is that these nutritional effects are the product of high population density, close contact with animals and a move to a high enery food with very little butritional diversity.

It cant have been too destructive or the whole concent would have been abandoned.

Annie Mouse said...

Also diet can change physique in a generation. Just look at Chinese folk living an American lifestyle. Compoare the young ones to their parents and grandparents. Compare the UK war generation with their short stature and bad teeth to the genetically near identical American soldiers.

I know an gentically indian fellow who's parents barely clear 5 feet. He is edging on 7 feet.

GailT said...

"The case for population replacement is very very far from proven and it cynical to state it as fact."

It is not cynical or even controversial to state that we see strong evidence of large scale replacement of pre-neolithic populations in Europe. At this point I don't see any other possible interpretation. Of course more ancient DNA data will provide a better picture, but both mtDNA and y-DNA indicate population replacement.

John Hawks wrote about this on his blog recently, a short excerpt: "These observations show that the present distribution of genetic variation is in some ways completely unrepresentative of the patterns in the past. The thing that strikes me: It takes a pretty massive demographic turnover to make this happen. And what we're looking at in today's populations is many, many instances of such turnovers during the last 20,000 years."

Iduna Depweg Borger said...

Bergmann's Rule applies to robusticity, not height. Warm weather means tall and thin, and cold weather means short and round, according to Carleton Coon. Another rule must be taken into account for height.

jeanlohizun said...

"It is not cynical or even controversial to state that we see strong evidence of large scale replacement of pre-neolithic populations in Europe. At this point I don't see any other possible interpretation. Of course more ancient DNA data will provide a better picture, but both mtDNA and y-DNA indicate population replacement.
"


How does modern distribution of Y-DNA Haplogroups or mt-DNA Haplogroups provide strong evidence for a total population replacement of Europe during at the onset of the Neolithic?

Dienekes said...

Bergmann's Rule applies to robusticity, not height. Warm weather means tall and thin, and cold weather means short and round, according to Carleton Coon. Another rule must be taken into account for height.

It applies to body size which is correlated with height. In northern latitudes body size increases, probably because the ratio of an organism's volume to its surface area is proportional to a length parameter, and hence heat retention is improved in organisms that are bigger. It is also, of course, related to the geometry of an organism, with an ellipsoid having a smaller such rate compared to a sphere.

In any case no matter what the explanation it's wrong to compare Neolithic with pre-Neolithic Europeans as if the two are a single population modified by a different diet.

Annie Mouse said...

@Gail

I prefer to read the journals and come to my own conclusions.

eurologist said...

"How does modern distribution of Y-DNA Haplogroups or mt-DNA Haplogroups provide strong evidence for a total population replacement of Europe during at the onset of the Neolithic?"

It only does if you use cyclical arguments, such as, "I assume this mtDNA haplogroup to be neolithic, I see it (barely) in the Mideast, ergo it must have been involved in agriculturalist replacement because I see it in Europe, which then also confirms it to be young."

Or: "I assume R to be young, and I believe in displacement, and find R in Europe -- so that proves displacement and confirms it is young."

GailT said...

"How does modern distribution of Y-DNA Haplogroups or mt-DNA Haplogroups provide strong evidence for a total population replacement of Europe during at the onset of the Neolithic?"

From several journal articles published in the few years, some of which include testing of ancient DNA: European mtDNA U5 hunter-gatherers were largely replaced by other mtDNA haplogroups; R1b became the dominant European y haplogroup probably within the last 4,000-8,000 years.

"I prefer to read the journals and come to my own conclusions."

We must not be reading the same journals. Obviously we need more ancient remains and more research, but the evidence in Europe and elsewhere is pointing to at least partial population replacement.

I don't believe that the present work proves complete replacement - it seems likely there was mixing with previous populations, especially for mtDNA. And I don't see any value in arguing with committed anti-migrationists. With more ancient DNA studies in progress and improvements in testing methods, we might not be too many years away from settling the issue.

jeanlohizun said...

“From several journal articles published in the few years, some of which include testing of ancient DNA: European mtDNA U5 hunter-gatherers were largely replaced by other mtDNA haplogroups; R1b became the dominant European y haplogroup probably within the last 4,000-8,000 years.”
Uhmm I find it interesting that some people seemed to have forgotten that the most dominant mt-DNA haplogroup today in Europe was already present in a Mesolithic European population. As for R1b or rather R-M269, it is dominant in nowadays Western Europe, not in Eastern. Anyhow what exactly do you mean by it became dominant within the last 4000-8000 years, and what does that have to do with replacement of European lineages?

Annie Mouse said...

LOL

Dienekes and I definitely read the same journals and still we disagree. We differ in our preconceptions.

(1) The ancient DNA data is very sparse. But if you look at Jean Manco's excellent resource:

http://www.buildinghistory.org/distantpast/ancientdna.shtml

You can see of the European 11 mitochondrial haplogroups found prior to the global neolithic 4 contain the CRS (H2a2a normally), a further 3 are consistent with H. Paglicci 23 (third oldest at 23k and clearly Cromagnon )cannot be U is is some subclade of HV. Only 4 were probably identified as U, only 1 further identified as probably U2 not U5.

Potentially that is 60% Paleo ithic H.

Wow that is higher than modern levels! (wry smile)


(2) So far ancient U has only been found in the north and in burials whereas the dominant form of death ritual in the north is likely to be cremation or boat burials. Perhaps these were immigrants with a different culture?

(3) There is NO paleolithic or mesolithic Y haplogroup data. So we have NO IDEA what the menfolk were. Probably "I" but its just a guess. It could be R1b or A for all we know.

(4) The oldest samples (only 2 sites) are all consistent with G2 IMO (or something similar) around 5,000 BC. Which happens to correspond exactly with the start of the neolithic in Europe. So we do not know if these folk were neolithic immigrants or converts. The Derenburg Meerenstieg II folk (Y haplogroup F*, probably G2 IMO) look like immigrants, as they match modern central Anatolia most closely. But G2 is very rare in Europe, and this population does NOT match modern Europe. So this is a potent argument AGAINST replacement by this group of neolithic incomers.

I could go on but its late and I am tired. I am not a committed anything by the way. But IMO the case is very FAR from proven. The mesolithic U is interesting but not the end of the story. I beleive there is a Portuguese paper due out shortly that could be interesting.

"With more ancient DNA studies in progress and improvements in testing methods, we might not be too many years away from settling the issue"

This I agree with.

Annie Mouse said...
This comment has been removed by the author.
Annie Mouse said...

Correction: I meant Paglicci 25 at 24k

Note also that the F* (the oldest known Y-haplogroup in Europe, from Derenburg Meerenstieg II) includes R1b. So it could just as easily be R1b as any other haplogroup in F*.

GailT said...
This comment has been removed by the author.
jeanlohizun said...

“Jean's website is a great resource, and note that she points out the unreliability of aDNA tests that were done without good control of contamination. Some of the rCRS results and partial results could be H or U, so those results are not conclusive, and if you look at aDNA in central and northern Europe (and restrict it to studies with good control for contamination), we have mostly U results until the neolithic. The sample is still to small to be convincing, but it certainly adds support to the theory of replacement.”
Well here is something rather interesting: Jean M doesn’t question the reliability of the study done on a Neolithic sample by Haak et al(2005), nor does she question the reliability of a second study done by Haak et al(2010) on Neolithic samples, even though both studies only analyzed the HVS-I region, and did not have “good control of contamination”, yet she questions the reliability of a study done on a Mesolithic sample by Chandler et al(2005), given that : “However this comes from a study carried out some years ago, when ancient DNA studies were less reliable” So given that 2005 isn’t that far away, and that the study done by Bramanti et al(2009) was based largely on Haak et al(2005), I can say that it is indeed hypocritical for someone to call one study unreliable based on the year it was done, while using another study done on the same year, using the same techniques, just because it fulfills the agenda being transmitted. In fact the study done by Bramanti et al(2009) doesn’t even address the issues of contamination, while only using the HVS-I. So tell me what makes the study done by Bramanti et al(2009) more accurate or reliable than that done by Chandler et al(2005). Perhaps it has to do with the fact that the study done by Bramanti et al(2009) serves the purpose of argument for those who so blindly advocate migrationism.
“All of the recent, high quality aDNA research supports large scale replacement of mtDNA and y-DNA in Europe during the neolithic, and you have to distort or misread the available evidence to reach an opposite conclusion”
Per what I mentioned above I think the statement mentioned above rather applies to you sir. So yes in my honest opinion it is cynical of you to claim that ancient DNA evidence points to replacement, when in any case, there was some local replacement, however there are many regions in Europe that exhibit continuity since pre-Neolithic times; trying to discard studies that are at odds with our beliefs without any solid proof of its unreliability points out to a personal agenda more than an objective analysis of the current data on ancient DNA studies. As for Y-DNA, well all populations so far analyzed with Neolithic cultures have turned out to be haplogroup G2a and F(xG,H,I,J,K), so given that no ancient -YDNA sampling has been done on Mesolithic European populations, any assumption for replacement is rather more of a wild theory than factual conclusions. In any case Western Europe nowadays isn’t dominated by G2a or F*.

Annie Mouse said...

I did read the paper. Even commented on the appendices. But I did not pay attention to the haplogroup as it seemed too broad and could not be identified with any accuracy. Plus because of the timing you could not pin it to a particular era.

My point is exacty that things are not clear cut and open to interpretation.

"Of course it is far from conclusive"

Glad we agree on this.

"But based on current evidence, you absolutely cannot call someone cynical for talking about scenarios involving population replacement"

No, but Dienekes is stating it as incontrovertable fact. That is cynical.

GailT said...

Jean's website is a great resource, and note that she points out the unreliability of aDNA tests that were done without good control of contamination. Some of the rCRS results and partial results could be H or U, so those results are not conclusive, and if you look at aDNA in central and northern Europe (and restrict it to studies with good control for contamination), we have mostly U results until the neolithic. The sample is still to small to be convincing, but it certainly adds support to the theory of replacement.

"Meerenstieg II...could just as easily be R1b as any other haplogroup in F*"

Haak et al 2010 plainly state that Meerenstieg II cannot possibly be R1b: "individuals deb20 and deb38 both fall basally on the F branch (derived for M89 but ancestral for markers M201, M170, M304, and M9), i.e., they could be either F or H"

All of the recent, high quality aDNA research supports large scale replacement of mtDNA and y-DNA in Europe during the neolithic, and you have to distort or misread the available evidence to reach an opposite conclusion. Of course it is far from conclusive, and perhaps new studies will find evidence of continuity from the mesolithic (and I would welcome any such results). But based on current evidence, you absolutely cannot call someone cynical for talking about scenarios involving population replacement.

argiedude said...

anti-migrationists

You're JeanM, right?

Annie Mouse said...

And rereading the paper

"deb34 proved to be ancestral for G1-M285 but derived for G2*-P287 and additional downstream SNP S126 (L30), placing it into G2a3"

I was wondering why I recalled it as likely G2.