Saturday, February 22, 2014

Replacement or continuity?


 
Inuit meat cache, Kazan River (source: Library and Archives Canada / PA-101294). Because of their high meat diet, hunters produce more body heat than farmers do. Natural selection has thus favored certain mtDNA sequences over others in humans with this profile of heat production. A change in selection pressure may therefore explain, at least in part, the genetic divide between late hunter-gatherers and early farmers in Europe.
 

Who were the ancestors of present-day Europeans? The hunter-gatherers of the Paleolithic and the Mesolithic? Or the Neolithic farmers who began to spread out of the Middle East some 10,000 years ago?

This debate has teetered back and forth for the past thirty years. On the basis of various genetic polymorphisms, L.L. Cavalli-Sforza and his students argued that Europeans are largely descended from Middle Eastern farmers (Ammerman and Cavalli-Sforza, 1984; Cavalli-Sforza et al., 1994). On the basis of mtDNA and Y chromosomal data, two other research teams, one led by Martin Richards and the other by Ornella Semino, maintained that the European gene pool is over 75% of native hunter-gatherer origin (Richards et al., 2000; Semino et al., 2000). If we look only at the present-day gene pool, Europeans seem far too differentiated to be the descendants of Neolithic farmers from the Middle East.

Over the last few years, new evidence has swung the debate back to the model of population replacement. By retrieving DNA from ancient skeletal remains, we can now compare the latest hunter-gatherers with the earliest farmers, and what we see is a sharp genetic divide between the two (Bramanti et al., 2009). The farmers seem to have been immigrants who replaced the hunter-gatherers. This is direct evidence, so what more is there to say? Facts are facts.

Yet there is always more to say. Facts may be illusory or, if real, wrongly interpreted. For one thing, wherever we have a fairly continuous time series of ancient DNA, the genetic divide no longer appears between the latest hunter-gatherers and the earliest farmers. It appears between the earliest farmers and somewhat later farmers. This is particularly so when we examine haplogroup U lineages, whose disappearance is widely seen as evidence for population replacement. According to a study of 92 Danish remains, these lineages remained common after the Neolithic and reached their current low prevalence only during the Early Iron Age (Melchior et al., 2010).

If this genetic divide is not solely due to population replacement, what else might be responsible? Mishmar et al. (2003) were the first to suggest natural selection:

Thus, extensive global population studies have shown that there are striking differences in the nature of the mtDNAs found in different geographic regions. Previously, these marked differences in mtDNA haplogroup distribution were attributed to founder effects, specifically the colonizing of new geographic regions by only a few immigrants that contributed a limited number of mtDNAs. However, this model is difficult to reconcile with the fact that northeastern Africa harbors all of the African-specific mtDNA lineages as well as the progenitors of the Eurasia radiation, yet only two mtDNA lineages (macrohaplogroups M and N) left northeastern Africa to colonize all of Eurasia (1, 2) and also that there is a striking discontinuity in the frequency of haplogroups A, C, D, and G between central Asia and Siberia, regions that are contiguous over thousands of kilometers. Rather than Eurasia and Siberia being colonized by a limited number of founders, it seems more likely that environmental factors enriched for certain mtDNA lineages as humans moved to the more northern latitudes.

[...] We now hypothesize that natural selection may have influenced the regional differences between mtDNA lineages. This hypothesis is supported by our demonstration of striking differences in the ratio of nonsynonymous (nsyn)/synonymous (syn) nucleotide changes in mtDNA genes between geographic regions in different latitudes. We speculate that these differences may reflect the ancient adaptation of our ancestors to increasingly colder climates as Homo sapiens migrated out of Africa and into Europe and northeastern Asia.

This hypothesis has since received support from Balloux et al. (2009):

We show that populations living in colder environments have lower mitochondrial diversity and that the genetic differentiation between pairs of populations correlates with difference in temperature. These associations were unique to mtDNA; we could not find a similar pattern in any other genetic marker. We were able to identify two correlated non-synonymous point mutations in the ND3 and ATP6 genes characterized by a clear association with temperature, which appear to be plausible targets of natural selection producing the association with climate. The same mutations have been previously shown to be associated with variation in mitochondrial pH and calcium dynamics. Our results indicate that natural selection mediated by climate has contributed to shape the current distribution of mtDNA sequences in humans.

Humans have to adapt to two sources of warmth: climate and internal body heat, which in turn varies with lifestyle and diet. Diet in particular results in different patterns of body heat production between hunter-gatherers and farmers, as explained by Speth (1983):

One aspect of protein metabolism relevant to this issue concerns the high "specific dynamic action" (SDA) of protein ingestion. The SDA of food refers to the rise in metabolism or heat production (diet-induced thermogenesis) resulting from the ingestion of food [...] The SDA of a diet consisting largely of fat is about 6- 14%, while that of a diet high in carbohydrates is about 6%. In striking contrast, the SDA of a diet consisting almost entirely of protein may be as high as 30%; or, in other words, for every 100 calories of protein ingested, up to 30 calories are needed to compensate for the increase in metabolism. Thus, persons whose diets are high in protein experience higher metabolic rates than those whose diets are composed largely of carbohydrate. For example, members of Eskimo populations, at least 90% of whose caloric needs were traditionally met by meat and fat (cf. Draper 1980:263; Hoygaard 1941), had basal metabolic rates 13 to 33% above the DuBois standard, which is based on the metabolic rates of populations consuming western diets (Itoh 1980:285).

Conclusion

Before ancient DNA became available, the prehistory of populations had to be inferred. The age of a genetic lineage was inferred from the degree of differentiation divided by the mutation rate. Since both variables could be known only approximately, the time depths of Europe's genetic lineages were likewise known only approximately.

Ancient DNA seems to promise a clearer picture because the only source of uncertainty is the age of the skeletal material. Unfortunately, this new method is more sensitive to uncertainty from another source: natural selection. Late hunter-gatherers and early farmers had to adapt to different environments. There certainly was a genetic divide between the two, but did it result from differences in origin or from differences in natural selection?

Natural selection distorts the picture if either method is used, since both assume that mtDNA is selectively neutral. The distortion is more serious, however, with the new method, which assumes selective neutrality across the genetic divide between late hunter-gatherers and early farmers—the very moment in prehistory when this assumption is most likely to fail. The old method assumes selective neutrality throughout the entire time depth of Europe’s genetic lineages—an assumption that may indeed be true over most of that time.

Even if the lineage has no selective value in and of itself, natural selection can still distort the picture. This is especially so for mtDNA:

Selection can change allele frequency even at a locus not responsible for fitness differences. Because there is little or no recombination in mitochondrial DNA, selection at one nucleotide affects the frequencies of all other variable nucleotides for the whole molecule. Selection on the nuclear genome, particularly nuclear-encoded proteins that are imported into the mitochondrion and X-linked markers that can have a high effective linkage to mtDNA, can also cause changes in the frequencies of mtDNA haplotypes. Equally importantly, selection on any other cytoplasmically inherited traits will directly affect the frequencies of mtDNA. (Ballard and Whitlock, 2004)

This is less of a problem with nuclear DNA because of recombination, but the problem remains if the presumably neutral gene is close to another gene of high selective value.

In raising these points, I am not trying to argue that Middle Eastern farmers made no contribution to the European gene pool. There is good archaeological evidence of these farmers pushing up the Danube and into central Europe. Elsewhere, however, the evidence for population replacement becomes weaker and the evidence for continuity correspondingly stronger. This is the conclusion that Zvelebil and Dolukhanov (1991) make with respect to northern and eastern Europe:

The transition to farming occurred very slowly and took a long time to complete, the whole process lasting 1500-4000 years. In the far north and northeast of Europe, the process was never completed. [...] Local hunter-gatherer societies played a significant role in the transition. There is strong evidence for continuity in material culture in most regions throughout the transition. Although this neither proves nor disproves the case for population movement associated with the transition (small groups of people could have migrated, leaving little or no trace in the archaeological record), such evidence does not support the colonization model for the transition to farming and it does indicate that local hunter-gatherer traditions were passed on from generation to generation during the long period of the adoption of farming.

And yet the advent of farming brought massive genetic change to northern and eastern Europe, including widespread decline of haplogroup U—the sort of change that is supposed to mean massive population replacement. Since farming began to spread to this region only 6,000 years ago, even later among the Finnish and Baltic peoples, there is only a very narrow time frame in which northern and eastern Europeans could have evolved their characteristic physical appearance, assuming of course that population replacement had actually happened.

Even in central Europe, where population replacement is well documented, we are still unsure whether it was permanent or temporary. Indeed, we see evidence of the replacers being later replaced, perhaps by natives who had never disappeared from the vicinity of the farming settlements (Haak et al., 2005; Rowley-Conwy, 2011).
 

References

Ammerman, A.J. and L.L. Cavalli-Sforza. (1984). The Neolithic Transition and the Genetics of Populations in Europe, New Jersey: Princeton University Press.

Ballard, J.W.O. and M.C. Whitlock. (2004). The incomplete natural history of mitochondria, Molecular Ecology, 13, 729-744.
http://dna.ac/filogeografia/PDFs/Ballard%26Whitlock_04_MTrev.pdf

Balloux F., L.J. Handley, T. Jombart, H. Liu, and A. Manica (2009). Climate shaped the worldwide distribution of human mitochondrial DNA sequence variation. Proceedings. Biological Sciences, 276 (1672), 3447-55.
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2817182/?tool=pmcentrez

Bramanti, B., M. G. Thomas, W. Haak, M. Unterlaender, P. Jores, K. Tambets, I. Antanaitis-Jacobs, M.N. Haidle, R. Jankauskas, C.-J. Kind, F. Lueth, T. Terberger, J. Hiller, S. Matsumura, P. Forster, and J. Burger. (2009). Genetic discontinuity between local hunter-gatherers and Central Europe's first farmers, Science, 326 (5949), 137-140.
http://jsarf.free.fr/palanthsci/Europe's%20First%20Farmers%20Were%20Immigrants.pdf

Cavalli-Sforza, L.L., P. Menozzi, and A. Piazza. (1994). The History and Geography of Human Genes, New Jersey: Princeton University Press.

Haak, W., P. Forster, B. Bramanti, S. Matsumura, G. Brandt, M. Tänzer, R. Villems, C. Renfrew, D. Gronenborn, K.W. Alt, and J. Burger. (2005). Ancient DNA from the first European farmers in 7500-year-old Neolithic sites, Science, 310 (5750), 1016-1018.
http://www.sciencemag.org/content/310/5750/1016.short

Melchior, L., N. Lynnerup, H.R. Siegismund, T. Kivisild, J. Dissing. (2010). Genetic diversity among ancient Nordic populations, PLoS ONE, 5(7): e11898
http://www.plosone.org/article/info%3Adoi%2F10.1371%2Fjournal.pone.0011898#pone-0011898-g002

Mishmar, D., E. Ruiz-Pesini, P. Golik, V. Macaulay, A.G. Clark, S. Hosseini, M. Brandon, K. Easley, E. Chen, M.D. Brown, R.I. Sukernik, A. Olckers, and D.C. Wallace. (2003). Natural selection shaped regional mtDNA variation in humans, Proceedings of the National Academy of Sciences (USA), 100 (1), 171-176.
http://www.pnas.org/content/100/1/171.full

Richards, M., V. Macaulay, E. Hickey, E. Vega, B. Sykes, et al. (2000). Tracing European founder lineages in the Near Eastern mtDNA pool, American Journal of Human Genetics, 67, 1251-1276.
http://www.sciencedirect.com/science/article/pii/S0002929707629541

Rowley-Conwy, P. (2011). Westward ho! The spread of agriculturalism from Central Europe to the Atlantic, Current Anthropology, 52 (S4), S431-S451.
http://arkeobotanika.pbworks.com/w/file/fetch/48307263/Rowley-Conwy%2011%20CA%20Farming%20westward.pdf

Semino, O., G. Passarino, P.J. Oefner, A.A. Lin, S. Arbuzova, et al. (2000). The genetic legacy of Paleolithic Homo sapiens sapiens in extant Europeans: A Y chromosome perspective, Science, 290, 1155-1159.
http://fboekelo.tripod.com/boekelo/GP/semino.pdf

Speth, J.D. (1983). Energy source, protein metabolism, and hunter-gatherer subsistence strategies, Journal of Anthropological Archaeology, 2, 1-31.
http://faculty.ksu.edu.sa/archaeology/Publications/Hearths/Energy%20source,%20protein%20metabolism,%20and%20hunter-gatherer%20subsistence%20strategies.pdf

Zvelebil, M. and P. Dolukhanov. (1991). The transition to farming in Eastern and Northern Europe, Journal of World Prehistory, 5, 233-278.
http://link.springer.com/article/10.1007/BF00974991

31 comments:

Anonymous said...

I'm currently thinking

->HGs
->HGs mostly but not completely displaced by east med. farmers
->reconquista including wandering Cucuteni types displaced by PIE
->actual IE layer

complicated by first farmer DNA surviving and increasing through the female line.

but my view changes by the day as new papers come out.

Anonymous said...

meant to add,

so some continuity, some replacement but mostly continuity by cousin.

barakobama said...

Peter Frost there is prove in ancient autosomal DNA European hunter gatherers and farmers were two different populations, and that modern Europeans have a very high amount of farmer ancestry. Have you read the study Laz 2013? They had very different mtDNA because they were two different populations NOT because of drift. Referencing sources from before the modern DNA era is not good for your argument.

In WHG-ANE-EEF admixture from laz 2013 southern Europeans come out overwhelmingly EEF(including early European farmer or other forms of near eastern ancestry), north-west Europeans are about 5-10% more EEF than WHG, east Europeans(Balkans-) have pretty equal EEF and WHG but EEF is usually higher, only in far north-east Europe is WHG higher than EEF and even then WHG only reaches above 50% in Sami(one north Norwegian Sami sample). There is a lot of near eastern ancestry in Europe, and overall is higher than European aka hunter gatherer ancestry.

I don't understand why there is no correlation between hunter gatherer ancestry and hunter gatherer mtDNA and Y DNA. Whatever the source of this is it effected almost all Europeans.

Peter, modern people in certain regions of Europe today may not be full blooded descendants of ones that lived there in the Neolithic. It seems you never consider that idea. Genomes from Mesolithic and Neolithic Swedes prove they are not the main ancestors of modern ones, that is just one example. In my opinion Indo Europeans brought more WHG and ANE to Europe and that there was modern like near eastern admixture in Europe especially Balkans and Italy after the Neolithic. High amount of WHG in north Europeans is probably because of migrations of Indo Europeans and Uralics from east Europe not because of native north European hunter gatherer ancestry.

Sean said...

"IT would be interesting to get data from fertility clinics to see if there are any groups or populations that struggle to conceive,” he says, “and if any of this can be put down to incompatibilities between mitochondria and nuclear backgrounds. Around 40% of pregnancies end in miscarriage and we don’t know why.”"

Mitonuclear match: Optimizing fitness and fertility over generations drives ageing within generations

Sean said...

'IT would be interesting to get data from fertility clinics to see if there are any groups or populations that struggle to conceive,” he says, “and if any of this can be put down to incompatibilities between mitochondria and nuclear backgrounds. Around 40% of pregnancies end in miscarriage and we don’t know why.”'

Mitonuclear match: optimizing fitness and fertility over generations drives ageing within generations

Sean said...

Peter doesn't have an answer for all the arguments, yet.

What percentage of current north Europeans came from Indo Europeans who were a bit of a mix of ice age Euro HG that wandered off and got mixed with other people, I don't know, and don't much care.

The essential point is not guesswork about who contributed what exotic strain, where they acquired it, or when they brought it back to north Europe; it's what is the continuity from the ice age to modern times in north Europe.

Current north Europeans must be at least 50% from the ice age hunter gatherer population of north Europe, my eyes tell me. So does the mirror.

barakobama said...

Sean, north European's hunter gatherer ancestry is not necessarily native to the region. I think Indo Europeans and Uralics from east Europe are mainly responsible.

Anonymous said...

"Current north Europeans must be at least 50% from the ice age hunter gatherer population of north Europe, my eyes tell me. So does the mirror."

No one can really argue with that kind of evidence, especially when the cut-off is as specific as "at least 50%."

Anonymous said...

@barak

"I think Indo Europeans and Uralics from east Europe are mainly responsible."

What you think of as "Uralic" extended from France to Siberia and into North America.

http://img571.imageshack.us/img571/6525/7dt9.png

It's the mammoth steppe not Siberia. The labeling is misleading people.

Once you see ANE as mammoth steppe rather than Siberian it all fits neatly.

Anonymous said...

FWIW, my husband, from N. Europe, starts sweating at 70 degrees. It kind of amazes me that it isn't obvious that people might run hotter or colder due to the temperatures their ancestors lived in.

Peter Fros_ said...

"They had very different mtDNA because they were two different populations NOT because of drift."

Barak,

Genetic drift and natural selection are two different things. Very different.

It is difficult to disentangle the effects of admixture and natural selection. Geneticists try to get around this problem by looking at noncoding DNA, but even noncoding DNA is not always selectively neutral and even when it is there may be a gene nearby that has high selective value.

Sean said...

Anon, everyone can make their own mind up. Naysayers may object that the turnover in mtDNA was far too abrupt to be a product of selection. However, and as Peter points out in this post, those all knowing critics are tacitly positing an incredibly intense degree of selection for skin pigmentation, hair and eye colour, skeletal, and especially craniofacial characteristics (the delicate features).

Possibly a factor in HG mtDNA vanishing was the agricultural diet, which may have imposed tough selection on most mtDNA from HG, because of the the different metabolic demands and altered supply of substrates .

Peter, apart from the mtDNA issue, is the selection of DNA caused by agriculture which you suggest, similar to what is called a 'soft sweep'?

barakobama said...

Peter frost I see no reason to argue this. Modern Europeans have very high amounts of near eastern(mainly from early farmers) ancestry that has been proven not just through mtDNA. 75% North Eurasian(including ANE) hunter gatherer ancestry may be accurate for north-east Europeans.

barakobama said...

Sean, European eye color had diversified by the Mesolithic both La Brana-1 and Loschbour had light eyes also we know some Mesolithic Europeans must of had brown eyes. I think many people assume European light pigmentation has to be very young(however your measuring it). When it was found Copper age people of the pontaic steppe "are inferred to have light skin pigmentation" they highlighted that they had darker eyes than modern Europeans(which ones). Many people took that information and assumed this means light eyes were less popular back then.

Peter suggested that Loschbour got his blue eyes from farmer admixture(in article brown man with blue eyes). Right there is an assumption the young invasive farmers were the light pigmented ones in every way and that the old native hunter gatherers were dark in everyway.

I think the biased assumption light pigmentation is very young(however your measuring it) hurts peoples chances of discovering how it evolved. Loschbour and La Brana-1 may have had anything from snow white to dark dark brown skin. I have given my reasons many times. I think it is more likely they had dark skin, but who knows life is very complicated and there are a lot of possibilities. I hate it when people go mainstream and ignore the evidence that there are undiscovered factors to human skin color. The only thing I am pretty certain about La Brana-1 and Loschbour is they had dark hair and light eyes.

Anonymous said...

Sean
"Anon, everyone can make their own mind up. Naysayers may object that the turnover in mtDNA was far too abrupt to be a product of selection."

Yeah I'm not saying it was all selection just that if the farmers had some particularly good genes that were strongly selected for - if that is what happened - then by definition the percentage of farmer dna must have gone up over time - perhaps dramatically - and so if true this gives us a clue as to what happened.

Sean said...

Barak, The trouble with you, and not only you, is you think if you say a trait came from somewhere, you think it's explained. That is just recursion, and evades the question of what the selection pressure that caused the trait to evolve actually was. How did Europeans get to look so different from people who live at the same latitude. The skin colour is not the only difference, look at the face shape.


In a comment here several years ago, I raised the possibilty that the evolution of blue eyes may have preceded the evolution of white skin. Peter replied that he had also thought about that.

I don't pretend to know exactly what selection pressure caused white skin to evolve in Europeans, but it had nothing to do with vitamin D; I am absolutely certain of it. And something along the lines of what Peter has been suggesting is the only other possibility.

Sean said...

If, as seems likely, farmers had bettter genes for farming, then with only a little intermarriage the useful farmer genes would have spread through the HG population.

All our mitochondial DNA is inherited from our mother. The offspring of farmer males and HG women would have the useful nuclear genes and hunter gatherer mtDNA. As I understand it Gregory Cochran says it couldn't have been selection within the hunter gatherers that removed their old hunter gather adapted mtDNA because the mtDNA disappeared too fast.


Invaders usually marry the local women, but it seems to me it follows from the aforemention assuptions of Cochran that there there was little or no intermarriage between HG women and farmers (otherwise the HG mtDNA would have persisted for a very long time). I find it difficult to believe that HG women would not have found their way into a flourishing farming community. As Duke Nukem said "Damn it!, Why do they always take the hot ones?"

barakobama said...

One event did not create the difference we see in farmer and hunter gatherer mtDNA in Europe today. We are talking about thousands of years of migrations, hundreds of different cultures and ethnic groups, gazillions of different individual stories, etc, etc, etc, etc.

Also it seems you guys are treating a mtDNA haplogroup the same why as a mutation that creates light eyes. mtDNA is a maternal line, so it is all about female giving birth to another female who gives birth to another female and so on. For some reason farmer females reproduced much better than hunter gatherer females. I don't understand why likely hunter gatherer decended mtDNa and farmer mtDNA is so evenly distributed in Europe and doesn't show any correlation with hunter gatherer Y DNA. Hunter gatherer Y DNA and mtDNA does not correlate really at all with hunter gatherer ancestry which is also very confusing.

A lot of mtDNA in Europe we now consider as descended from farmers(like H3) are very exclusive to Europe and most diverse in Europe, meaning they look like they originated in Europe. Before ancient mtDNA many people thought that those haplogroups were native to Europe like they thought U5 was. There may be mtDNA we think of as farmer mtDNA that is actually hunter gatherer mtDNA.

barakobama said...

Sean, what face shape in Europeans are you talking about? Can you please give evidence? The whole female selection thing to me is not convincing.

We now know(unlike in 2006) that Europeans can be very different from each other genetically and that there are two main sources of ancestry in Europe: near eastern(mainly from early farmers) and North Eurasian hunter gatherer(WHG and ANE). When Peter talks about the evolution of white skin in Europe he forgets that.

Near eastern ancestry may be as high as 40-50% in north-west Europe and east Europe, 80% in southern Europe, and 30% in north-east Europe and Scandinavia. Most Europeans are about as much or more near eastern than they are North Eurasian(WHG and ANE). It is very important to remember a large percentage of modern Europeans ancestors were not living in the near east 10,000 years ago.

barakobama said...

I meant to say were living in the near east 10,000 years ago, not Europe or somewhere else in north Eurasia.

Also Sean, eye color is directly connected with hair color. light eyes existed in Mesolithic Europeans so there is a good chance light hair also existed or it evolved in their descendants. If light hair did not exist in the Mesolithic it probably evolved in Europeans during the Neolithic who had mainly North Eurasian(mainly WHG not ANE) ancestry which could explain why light hair-eyes-skin correlate so well with WHG.

Possible it was just luck that 2/2 Mesolithic Europeans so far tested(or whatever) have light eyes and light eyes were actually a small minority. I don't understand how light eyes could have been popular In a dark skinned black haired WHG people, while today is connected with light hair and light skin and happens to also be connected with WHG. If light hair and skin originated in the farmers why are Sardinians and southern Europeans in general much more dark haired and also have tanner skin? I understand crazy stuff can happen but I think there is a possibility that some region of Europe(i.e., east) the hunter gatherers were pigmented like modern Finnish.

Sean said...

There you go again: thinking you have explained traits by saying they came from some geographical area.

If white skin is not for enhanced skin synthesis of vitamin D, then Peter must be more or less right. Vitamin D has been quite well studied and it is pretty well established that white skin does not provide any advantage, the differences between groups are due to metabolism. I got as bored posting about this as everyone became while reading about it, but the spokesman for the Institute of Medicine of the National Academies panel that reported on vitamin D explains here. If light skin would not have been any use to HG (or farmers), in relation to vitamin D, then it must have evolved as a result of the kind of thing Peter suggests.

Interpretation of the recent genetic data is still uncertain, but I think it follows from the facts the IoM have established about vitamin D that this idea farmers were the first white skinned people is wrong.

Face shape and Eye color link to face shape. So light skin blue eyes and feminine face shape all came form the same place.

As for mtDNA, Nick Lane full paper on Mitonuclear match shows optimizing fitness is requires 'respiratory
stoichiometry to be calibrated locally to need, tailoring supply to demand'. Farming would have different requirements, sustained effort on a substantially different major substrate. There would be far less protein and vastly more starch. And the stress on the mitochondria would be combined with the energy expenditure demands of farming, which appear to have been selected for in muscle . If there has to be a close match between mtDNA and nuclear DNA, as Lane says, then farmers who had HG mothers could could have been under strong selection for optimisation of the match.

(Mild poisons, like other stresses, can have a hormetic effect. But that is a different issue.)

Sean said...

Correct link for Nick Lane paper

Sean said...

Review article Mitochondrial DNA: more than an evolutionary bystander

Sean said...

Increased intrinsic mitochondrial function in humans with mitochondrial haplogroup H
Increased "mitochondrial respiratory capacity per mitochondrion."

barakobama said...

Honestly Peter's theories anger me and seem very raciest. That doesn't mean I will be biased though, trust me. Does Peter consider anything besides female selection? I read "Female face shape and sexual selection" and "Eye color, face shape, and perceived personality traits" multiple times.

What Peter says about climate and lifestyle helping determine whether males or females are sexually selected makes sense, but you can't generalize the lifestyle of stone age hunter gatherers who lived in north Eurasia(WHG and don't forget about ANE) from around 50,000-10,000BP and say the same rule stood for all of the different people over ~40,000 years of time.

Also why would pale women over thousands and thousands of years always be the ones who are selected? I don't understand why faces would become more female like because of selection of pale skinned, light eyes, and light haired females(maybe separately). That is probably why Peter mentioned that light haired or eyes boys receive more estrogen in the womb, which feminizes the face. Besides that I don't why the faces would be more feminine.

I am not even a nube in anthropology(haven't started researching at all). I do have some very basic knowledge like I can tell differences between Caucasian skulls shape and others and the difference between archaic and modern human skulls. I have heard multiple times that Mesolithic/Upper Palaeolithic Europeans were very robust while the near eastern farmers were gracile(skinny?). We now know through ancient DNA the hunter gatherers were likely mainly blue eyes and the farmers brown eyed. Also WHG/ANE(simply Upper Palaeolithic north Eurasian) is over 50% in northern Europe while in southern Europe EEF(any near eastern ancestry goes in this category) is over 70%. This contradicts what Peter has said about blue eyed men having less robust faces.

I have also heard(no sources) that modern north Europeans(who are mainly blue eyed)are more robust than mainly brown eyed southern Europeans and near easterns. I have heard the phrase gracile Meditreaen body build many times.

I have also noticed that light haired men tend to grow less body hair(no sources).

I think modern culture could also be a reason why light hair and eyes are associated with females. I have read(and saved links) of studies that tested this. Men are constantly more blue eyed than women, women are much more green eyed than men, and women are more brown eyed than men. I couldn't find a study that showed a higher percentage of light hair in women. One from the 1930's(in Sami) said men were more light haired than the women.

Many women want to be blonde haired in our culture SO TONS OF THEM DYE IT. I can name many in my own family who naturally have dark hair(like most of the men) but dye it bright blonde. Also northern-eastern-central European children are primarily blonde haired and most of them become dark haired as adults. Look at small town school year books(where no one leaves) compare hair color between high school students and pre school, there is a big difference. Maybe women's hair color doesn't darken as much as men with age, or women who had blonde hair as children dye it and make themselves believe its their natural hair color.

Anonymous said...

I have also heard(no sources) that modern north Europeans(who are mainly blue eyed)are more robust than mainly brown eyed southern Europeans and near easterns. I have heard the phrase gracile Meditreaen body build many times.

Good point. Don't northern Europeans tend to be more robust than southern Europeans? The Mediterranean type tends to be gracile. There is the "bleached Mediterranean" type among northern Europeans, but there is also the wider face, thicker boned robust type common among northern Europeans. I think Coon said it was Upper Paleolithic admixture and the Borreby type.

The wrestler Brock Lesnar would be a good example:

http://stiriwrestling.files.wordpress.com/2012/05/brock-lesnar.jpg

Bones and Behaviours said...

There seems to be physical continuity between the Magdalenians through the Ertebolle people to modern day Phalians. Clearly there was more admixture than some might let on, though natural selection means that phenotype can be misleading as to the overall genetic relationships between populations.

barakobama said...


Anonymous I don't think north Europeans are very robust. From my own experience most are about 5'10-6'0 and about 170-200Ibs. I have not seen many southern Europeans but from the ones I have seen they have the exact same body builds. Maybe anthropologist can notice little differences.

Guide to Spainish phenotype.

http://www.theapricity.com/forum/showthread.php?106927-Guide-to-Spanish-phenotypes-%28by-regions%29

Here are Google images results of the most farmer(Sardinians) and most hunter gatherer(WHG+ANE) Europeans(Finnish but some Baltic people may be more).

Finnish
https://www.google.com/search?q=finnish+people&source=lnms&tbm=isch&sa=X&ei=GswPU5nfC-PayAHTq4DICQ&sqi=2&ved=0CAcQ_AUoAQ&biw=1024&bih=651

Sardinians
https://www.google.com/search?q=finnish+people&source=lnms&tbm=isch&sa=X&ei=GswPU5nfC-PayAHTq4DICQ&sqi=2&ved=0CAcQ_AUoAQ&biw=1024&bih=651#q=Sardinian+people&tbm=isch

Maybe you can't see it in a comparison of Sardinians and Finnish, but I have always noticed a similar look in all Europeans and it must come from the same source. Is it from EEF, is it from WHG, is it from ANE, is it from hunter gatherer-farmer mutts? I am very undecided on how it all developed right now.

Anonymous said...

By robust I don't mean tall and heavy necessarily. I mean morphology.

Anonymous said...

By robust I don't mean tall and heavy necessarily. I mean morphology.

I don't think modern studies like Karen Baab's or Lahr's find statistically detectable cranial robusticity differences between Northern and Southern Europeans, or greater robusticity related variation in Northern Europeans.

I also don't think they find a clear pattern of "Mediterranean" long facial indexes connecting to lower robusticity.

One note here is that bioanthropologists tend to denote robusticity as particular features of crania, such as the brow ridge, or a robust shape to the zygoma, whereas I've noticed that some lay folks outside bioanthropology seem to describe a broad face itself as robust (which seems an odd idea to me, because thereby such a definition children's faces would be more robust than adults).

Sean said...

As usual Peter, you have got it right. Just a slight modification of the argument.

People who burn off energy through heat generation in their mitochondria are wasting energy, which does not matter if there is enough food or bodyfat (energy supply).

Assuming European hunter gatherers had mitochondria that were adapted to using a high proportion of the energy in food for heat generation and they took up agriculture. Hunter–gatherers have less famine than agriculturalists. The famines would kill off those with the mtDNA that tended to waste more energy in generating heat.

The early farmers in Europe would have crops that were poorly adapted to northern climes. Moreover, farmers would be expending a lot of energy months in advance of harvesting; working on their fat reserves if the harvest had failed last year. Most hunter gatherers who took up farming would have mtDNA very badly adapted to their new mode of existence. One can easily imagine most common lines of hunter gatherer mtDNA in farmers disappearing very fast in famines.