Wednesday, December 27, 2006

Iran, oil and nuclear energy (or weapons?)

I thought it was interesting that a paper like this showed up in PNAS. Basically, maybe Iran's intentions really are good. (the paper is open access, so see link)

The Iranian petroleum crisis and United States national security

Roger Stern

PNAS Early Edition

Abstract: The U.S. case against Iran is based on Iran's deceptions regarding nuclear weapons development. This case is buttressed by assertions that a state so petroleum-rich cannot need nuclear power to preserve exports, as Iran claims. The U.S. infers, therefore, that Iran's entire nuclear technology program must pertain to weapons development. However, some industry analysts project an Irani oil export decline [e.g., Clark JR (2005) Oil Gas J 103(18):34-39]. If such a decline is occurring, Iran's claim to need nuclear power could be genuine. Because Iran's government relies on monopoly proceeds from oil exports for most revenue, it could become politically vulnerable if exports decline. Here, we survey the political economy of Irani petroleum for evidence of this decline. We define Iran's export decline rate (edr) as its summed rates of depletion and domestic demand growth, which we find equals 10-12%. We estimate marginal cost per barrel for additions to Irani production capacity, from which we derive the "standstill" investment required to offset edr. We then compare the standstill investment to actual investment, which has been inadequate to offset edr. Even if a relatively optimistic schedule of future capacity addition is met, the ratio of 2011 to 2006 exports will be only 0.40-0.52. A more probable scenario is that, absent some change in Irani policy, this ratio will be 0.33-0.46 with exports declining to zero by 2014-2015. Energy subsidies, hostility to foreign investment, and inefficiencies of its state-planned economy underlie Iran's problem, which has no relation to "peak oil."

Saturday, December 23, 2006

Science breakthroughs of the year and areas to watch in 2007

The #1 breakthrough according to Science was the proof of the Poincare conjecture. The runners-up are, in order: (see here for all the relevant pubs)

- Sequencing of Neanderthal autosomal DNA
- The worlds two great ice sheets losing ice to the oceans, at an accelerating pace
- Discovery of a fossil of a fish/amphibian.. "missing link" between water and land dwellers
- Cloaking technology: playing around with optics
- advances in understanding and treating age-related macular degeneration
- genetics of biodiversity and speciation
- new microscopy technology that gives clearer view of cells and proteins.
- the role of long-term potentiation in the formation of memory.
- the discovery of piRNAs, another class of small RNA molecules.

Areas to watch in 2007.

I won't list them all here, but obviously more genetic stuff (including whole genome association studies), and global warming.

Also in this issue of Science is a profile of Bruce Lahn. Check out GNXP on this.

Friday, December 22, 2006

Elevated ethnocentrism in the first trimester of pregnancy

This paper seemed really cool at first glance but then I was disappointed when I read it. It basiacally supports the hypothesis that during the first trimester of pregnancy in-group favoritism is at the most heightened state of the whole pregnancy because this is when the mother's immune system is on its highest alert.
The major thing that I did not like about it was that the title says ethnocentrism but then the research looks at American vs. non-American, so not so much at ethnicity, per se, after all.

Elevated ethnocentrism in the first trimester of pregnancy

Carlos David Navarrete, Daniel M.T. Fessler and Serena J. Eng

Evolution and Human Behavior Volume 28, Issue 1 , January 2007, Pages 60-65

Abstract: Recent research employing a disease-threat model of the psychology of intergroup attitudes has provided preliminary support for a link between subjectively disease-salient emotional states and ethnocentric attitudes. Because the first trimester of pregnancy is a period of particular vulnerability to infection, pregnant women offer an opportunity to further test this association. We explored the expression of intergroup attitudes in a sample of pregnant women from the United States. Consistent with the predictions of the disease-threat model, results from our cross-sectional study indicate that favoritism toward the ingroup peaks during the first trimester of pregnancy and decreases during the second and third trimesters. We discuss this finding in light of the possible contributions of cultural and biological factors affecting ethnocentrism.

Wednesday, December 20, 2006

CNVs and human-chimp differences

Evolgen has covered the recent papers on CNVs and he has another one up about how CNVs might help us explain phenotypic differences between chimpanzees and humans. There is a paper by Hahn that will be coming out soon in PLoS One. This journal has still not published its first issue.

Tuesday, December 19, 2006

Samuel Bowles on group competition and relatedness as important factors in human cooperation

I thought I would go over some more of the details of this paper by Samuel Bowles in Science. I had briefly covered it in a recent post. The paper hasn't gotten as much coverage as I think it deserves so I'll try to spread the meme here.
My understanding of it, in a (long) sentence is that using the Price Equation for the evolution of altruism which takes into account the balance of a within-deme and between deme effect, and some estimates of group competition and within-group relatedness among modern hunter-gatherers, S. Bowles argues that with group competition and group relatedness being high enough (and he provides evidence that it may indeed have been) and with reproductive leveling due to monogamy (thereby reducing the amount of intra-group competition), human large scale cooperation can flourish.

Ok, that was a long sentence. Maybe a shorter way of saying this is that cooperation in humans is largely due to the relatedness of people within groups, along with the fact that conflict between groups was frequent enough and that reproductive leveling (monogamy) offset any possibility that within-group competition would increase too much.

Some questions:

Is it safe to make the assumption that the extent of group warfare we see in today's hunter-gatherers closely approximates what it was for most of our hominin evolution? - not so sure about that. Bowles actually notes that "even very infrequent contests would have been sufficient to spread quite costly forms of altruism. He also thinks that recurrent warfare would explain the frequent catastrophic mortality and very slow growth rates seen in human demographic history.

Is it safe to assume that levels of relatedness among individuals in groups was the same now in hunter-gatherers as it was for most of our hominin evolution? - I'm not very clear on how/where S. Bowles gets his data for relatedness among the hunter-gatherer groups and also why if they are so surprisingly high (just under that for cousins) no one else would have noticed this before.

I have always had a strong intuition that human cooperation is greatly strenthened by relatedness within groups and non-relatedness between groups and by group conflict. I had never thought of the importance of reproductive leveling. Sam Bowles gives these ideas which resemble the arguments of group selection) some empirical and theoretical strength.

These ideas have been passed around before, but it seems that the multilevel-selection approach to understanding human cooperation has gained much more acceptance recently.

Saturday, December 16, 2006

Tradeoffs: UV, Folate, vitamin D, pregnancy loss

gotta love the name of this gene .... mthfr..... anyway, here's a short letter about multiple selective pressures and tradeoffs relating to folate metabolism and UV and the gradient of a particular genotype across northern to southern Europe, and also across N to S Americas.

Ultraviolet radiation represents an evolutionary selective pressure for the south-to-north gradient of the MTHFR 677TT genotype

Loren Cordain, Matthew Hickey

American Journal of Clinical Nutrition, Vol. 84, No. 5, 1243, November 2006

The pubmed link to this paper is not functioning properly and there is no abstract to link to, but here's the full-text below without the references.

In a recent issue of the Journal, Guéant-Rodriguez et al (1) and Devlin et al (2) confirmed prior observations (3) of a nutrient-gene interaction between methylenetetrahydrofolate reductase (MTHFR) and folate status. Homozygosity for the MTHFR 677TT genotype converts an alanine to a valine at position 222 in the amino acid sequence and reduces the enzyme activity, which causes hyperhomocysteinemia (4), which in turn increases the risk for cardiovascular disease, cognitive dysfunction, Alzheimer disease, and osteoporotic fractures (5), as well as recurrent early pregnancy loss (6, 7). These pathophysiologic sequelae likely materialize only when folate status is compromised (1, 2). Hence, it has been suggested that MTHFR 677TT genotype homozygosity may confer survival value in populations with sufficient dietary folate (8, 9), because this polymorphism is protective against colon cancer (10) and acute lymphatic leukemia (11), perhaps by contributing methylenetetrahydrofolate to DNA synthesis and thereby preventing double-strand DNA ruptures (12).

In addition to reduced dietary folate intake and absorption, it is less well appreciated that other environmental factors, including dermal exposure to ultraviolet (UV) radiation, may adversely influence folate status (13, 14). Exposure of human plasma in vitro to simulated strong sunlight causes a 30–50% loss of folate within 60 min, and light-skinned patients chronically exposed to UV radiation for dermal disorders maintain low plasma folate concentrations, which suggests in vivo dermal photolysis of folate (13). In contrast, dark skin (via its greater concentration of melanin) may prevent UV photolysis of folate (13, 14).

In European populations, a simultaneous south-to-north gradient exists for dermal pigmentation (14) and the presence of MTHFR 677TT (15). The prevalence of MTHFR 677TT decreases in a south-to-north manner: 10–12% of light-skinned Northern Europeans maintain the MTHFR 677TT genotype (2), but the highest frequency of this polymorphism occurs in more dark-skinned Southern Europeans, such as Sicilians (1). A similar, simultaneous and latitudinally dependent gradient in the frequency of the MTHFR 677TT allele (16, 17) and dermal pigmentation (14) has been found in the Americas.

As human populations move into more northern latitudes where they are exposed to less annual UV radiation, the evolutionary selection for less pigmented, lighter skin may represent an asset in that it can improve vitamin D status and lessen the risk for rickets and other vitamin D–related disorders (14). However, because lighter skin contains less protective melanin, it represents a liability with respect to folate metabolism, because lighter skin may be more susceptible than darker skin to photolysis of folate (13). Hence, to counter the increased loss of folate in lighter-skinned populations during seasonal exposure to UV sunlight, genes that lower plasma homocysteine concentrations by favoring increased the synthesis of MTHFR would convey selective advantage, perhaps by reducing recurrent early pregnancy loss (6, 7). The risk of recurrent early pregnancy loss in those who are homozygous for the MTHFR 677TT genotype is 2- to 3-fold that in those who maintain the wild or heterozygous genotype (6). In females of reproductive age, recurrent early pregnancy loss caused by impaired folate status represents the most likely environmental pressure favoring the selection of protective genotypes such as MTHFR 677CC, because cardiovascular disease, cognitive dysfunction, Alzheimer disease, and osteoporotic fractures typically occur in the postreproductive years.

Thursday, December 14, 2006

On the need and preference for the costly punishment option

The efficient interaction of indirect reciprocity and costly punishment

Bettina Rockenbach and Manfred Milinski

444, 718-723 (7 December 2006)

Abstract: Human cooperation in social dilemmas challenges researchers from various disciplines. Here we combine advances in experimental economics and evolutionary biology that separately have shown that costly punishment and reputation formation, respectively, induce cooperation in social dilemmas. The mechanisms of punishment and reputation, however, substantially differ in their means for 'disciplining' non-cooperators. Direct punishment incurs salient costs for both the punisher and the punished, whereas reputation mechanisms discipline by withholding action, immediately saving costs for the 'punisher'. Consequently, costly punishment may become extinct in environments in which effective reputation building—for example, through indirect reciprocity—provides a cheaper and powerful way to sustain cooperation. Unexpectedly, as we show here, punishment is maintained when a combination with reputation building is available, however, at a low level. Costly punishment acts are markedly reduced although not simply substituted by appreciating reputation. Indeed, the remaining punishment acts are concentrated on free-riders, who are most severely punished in the combination. When given a choice, subjects even prefer a combination of reputation building with costly punishment. The interaction between punishment and reputation building boosts cooperative efficiency. Because punishment and reputation building are omnipresent interacting forces in human societies, costly punishing should appear less destructive without losing its deterring force.

Tuesday, December 12, 2006

More on CNVs in the human genome

A Comprehensive Analysis of Common Copy-Number Variations in the Human Genome

Kendy K. Wong, Ronald J. deLeeuw, Nirpjit S. Dosanjh, Lindsey R. Kimm, Ze Cheng, Douglas E. Horsman, Calum MacAulay, Raymond T. Ng, Carolyn J. Brown, Evan E. Eichler, and Wan L. Lam

Am. J. Hum. Genet.
, 80:91-104, 2007

Abstract: Segmental copy-number variations (CNVs) in the human genome are associated with developmental disorders and susceptibility to diseases. More importantly, CNVs may represent a major genetic component of our phenotypic diversity. In this study, using a whole-genome array comparative genomic hybridization assay, we identified 3,654 autosomal segmental CNVs, 800 of which appeared at a frequency of at least 3%. Of these frequent CNVs, 77% are novel. In the 95 individuals analyzed, the two most diverse genomes differed by at least 9 Mb in size or varied by at least 266 loci in content. Approximately 68% of the 800 polymorphic regions overlap with genes, which may reflect human diversity in senses (smell, hearing, taste, and sight), rhesus phenotype, metabolism, and disease susceptibility. Intriguingly, 14 polymorphic regions harbor 21 of the known human microRNAs, raising the possibility of the contribution of microRNAs to phenotypic diversity in humans. This in-depth survey of CNVs across the human genome provides a valuable baseline for studies involving human genetics.

Monday, December 11, 2006

Another one on lactose tolerance

This paper is very similar to the recent one in Human Genetics that identified the T/G-13915 SNP in a Sudanes population. Here, Tishkoff et al. identify two other SNPs in a population of Kenyans, Tanzanians and Sudanese. I wonder if there's some sort of rivalry going on between these two groups.

Convergent adaptation of human lactase persistence in Africa and Europe

Sarah A Tishkoff, Floyd A Reed, Alessia Ranciaro, Benjamin F Voight, Courtney C Babbitt, Jesse S Silverman, Kweli Powell, Holly M Mortensen, Jibril B Hirbo, Maha Osman, Muntaser Ibrahim, Sabah A Omar, Godfrey Lema, Thomas B Nyambo, Jilur Ghori, Suzannah Bumpstead, Jonathan K Pritchard, Gregory A Wray & Panos Deloukas

Nature Genetics Published online: 10 December 2006;

A SNP in the gene encoding lactase (LCT) (C/T-13910) is associated with the ability to digest milk as adults (lactase persistence) in Europeans, but the genetic basis of lactase persistence in Africans was previously unknown. We conducted a genotype-phenotype association study in 470 Tanzanians, Kenyans and Sudanese and identified three SNPs (G/C-14010, T/G-13915 and C/G-13907) that are associated with lactase persistence and that have derived alleles that significantly enhance transcription from the LCT promoter in vitro. These SNPs originated on different haplotype backgrounds from the European C/T-13910 SNP and from each other. Genotyping across a 3-Mb region demonstrated haplotype homozygosity extending >2.0 Mb on chromosomes carrying C-14010, consistent with a selective sweep over the past 7,000 years. These data provide a marked example of convergent evolution due to strong selective pressure resulting from shared cultural traits—animal domestication and adult milk consumption.

Friday, December 08, 2006

Group competition, relatedness, and the evolution of human altruism

Science and Nature both seem to love research on human altruism/cooperation. Here is the latest by Sam Bowles from the Santa Fe Institute. The argument that he makes and the empirical and modeling evidence that he uses implies that human cooperation can be partly attributed to genetic relatedness between groups and conflict with other a sort of group/kin selection, the two of which are basically the same. There's a commentary by Rob Boyd and a related paper by Marin Nowak on the five rules for the evolution of cooperation (see below). Sam Bowles uses some relatedness data from modern hunter gatherers where the average degree of relatedness between group members turn out to be almost as high as cousins. I haven't looked too closely yet at how all this was measured, but sounds compelling.

Group Competition, Reproductive Leveling, and the Evolution of Human Altruism

Samuel Bowles

Science 8 December 2006:Vol. 314. no. 5805, pp. 1569 - 1572

Abstract: Humans behave altruistically in natural settings and experiments. A possible explanation—that groups with more altruists survive when groups compete—has long been judged untenable on empirical grounds for most species. But there have been no empirical tests of this explanation for humans. My empirical estimates show that genetic differences between early human groups are likely to have been great enough so that lethal intergroup competition could account for the evolution of altruism. Crucial to this process were distinctive human practices such as sharing food beyond the immediate family, monogamy, and other forms of reproductive leveling. These culturally transmitted practices presuppose advanced cognitive and linguistic capacities, possibly accounting for the distinctive forms of altruism found in our species.

Five Rules for the Evolution of Cooperation

Martin A. Nowak

Science 8 December 2006:Vol. 314. no. 5805, pp. 1560 - 1563

Abstract: Cooperation is needed for evolution to construct new levels of organization. Genomes, cells, multicellular organisms, social insects, and human society are all based on cooperation. Cooperation means that selfish replicators forgo some of their reproductive potential to help one another. But natural selection implies competition and therefore opposes cooperation unless a specific mechanism is at work. Here I discuss five mechanisms for the evolution of cooperation: kin selection, direct reciprocity, indirect reciprocity, network reciprocity, and group selection. For each mechanism, a simple rule is derived that specifies whether natural selection can lead to cooperation.

Wednesday, December 06, 2006

Four Stone Hearth Anthropology Blog Carnival - 4th Edition

Welcome to the fourth edition of the Four Stone Hearth Anthropology Blog Carnival. The excitement that was generated from all the Neanderthal DNA papers will be a hard act to follow, but it looks like we have many excellent, thought provoking submissions. We’ll go field by field and due to my bias, we'll begin with Biological Anthropology.

Biological Anthropology

Afarensis starts us off with a great review of a recent paper describing the results of an experiment where one species of baboon was mated (willingly or not, I don't know) with another species of baboons mainly to see if good (heterosis) or bad things (dysgenesis) resulted. The authors note that this is a good model with which to examine the likelihood of hybridization between homo species. One thing I remember from this paper was that the matings were always the male of one species with the female of the other species, or some sort of analogous asymmetry.

In light of all the exciting things happening in Molecular Anthropology these days, I'm happy that Kambiz from submitted his piece on copy number variation (CNV in the human genome. Kambiz does a really thorough job of introducing the basic concepts and the major findings from the study. As we continue to study the genomes (and continue to develop better ways to look at it) we are finding more and more sources of complexity. If I remember correctly, the researchers were able to assess a small fraction of these CNVs (only the big ones) as most of them are small repeats. Kambiz reviews the health implications these CNVs might have and how they cluster human population-wise.

Cultural Anthropology

Martin Rundkvist's submission called Leave the Ghetto from his blog Saltos Sobrius is very thought provoking and throws up the question of whether distinct minority cultures and ethnicities should be maintained or encouraged under a nation-state system. He makes the argument that to reduce inequalities, the minority cultures/ethnicities must "assume places inside majority society through education and employment". Even with programs like affirmative action in the US, progress in this area is very slow, highlighting the extent to which the generational cycle of economic class is very hard to break. This goes hand in hand with the fact that when times are tough, humans tend to rely even more on their groups (ethnic or otherwise) as buffering and support systems. This provides me with the perfect segue to the next submission about how disconnected our modern lives may be.

William Klinger at Nomadic Thoughts has submitted his post entitled Social (dis)connections. He discusses a New York Times op-ed piece which talks about how our social lives have been transformed from many face to face interactions to interactions through text and voice. I have heard stories about how the circle of friends of average Americans has been getting smaller as we lead more individualistic lives. The author of this piece presents a balanced description of what may be going on. As Will Klinger puts it: "The reason Johnson’s post satisfies me is because it strikes a happy medium between a hypersensitivity to the effects of technology in our lives on the one hand and the unbridled technophilia that so many of my generation have succumbed to"

Over at Wanna be an Anthropologist, Paul Wren has submitted a post about Anthropology on the Moon. In it, he discusses how NASA plans to install a permanent base on the moon where people will be stationed. He then discusses all the things that anthropologists might like to study in this type of a living situation (development of culture, social dynamics, marriage and kinship) I've often wondered myself if there are anthropologists out there taking down data from TV shows like Survivor.

Lexis2Praxis has a post at that examines the anthropology of the modern office space. Like any living environment of humans, each place develops its own set of cultural norms. These are discussed in the post. It reminds me of the movie Office Space. There is also a post on our networked culture and who gets to participate and who doesn't.

Lucy Jr. at The Second Sight has this entry which is a commentary on paleoanthropologists behaving badly over the Hobbit find in Flores Island, Indonesia. According to Lucy Jr., actions taken and the interpretation of the find was not so much of scientists interpreting a discovery, as a drama of passion, jealousy and old rivalries. Please click on the links of the characters in this story, as I was pleasantly surprised to see links to websites of actual researchers who, I assume, are working in Flores.

Stolen and Looted: Cultural History Lost and Destroyed for a Buck is the title of a post by Carl Feagans at Hot Cup of Joe. Here, we learn that many archaeological sites in Peru, Iraq, South East Asia and the American Southwest are under the threat of looting for archaeological treasures that can be sold for profit. Some quite stunning photos of looted sites are shown in the post...pretty surreal!! Also, check out his other post: Stolen and Looted: Who Does the Past Belong To? for related information.

K. Kris Hirst at has submitted an interesting piece on Damascus Steel. Apparently this is a type of steel used to make blades around the 11 or 12th century AD that seems to be very sophisticated and must have required a high level of technology to make, thus mystifying archaeologists.

Last but not least, Johan Normark at Archaeolog has submitted a post on Polyagentive Archaeology. "The polyagentive approach primarily differs from the humanocentric archaeology in that it tries to decentralize the human, to give an account of active tangible archaeological materialities and intangibilities (anything that can be perceived but which is not solid or palpable). This approach also aims to initially de-culturalize and de-socialize the past by emphasizing what lasts, differentiates and repeats."

Well, there we are. I hope that everyone enjoys this. I think we had a good turnout from the Cultural Anthropologists and the Archaeologits. It would have been nice to have a few more bio submissions (I'll take some blame for that, given my lack of a submission) and some linguistic submissions.

Tuesday, December 05, 2006

Requesting submissions for Four Stone Hearth Anthropology Blog Carnival

If any of you bloggers out there have any submissions for the latest edition of the Four Stone Hearth Anthro. Blog Carnival, please email them as soon as possible to These can be any posts related in any way to Anthropology. I will then put all the submissions together in a sort of highlights post of all the submissions, meant to reflect what is being blogged about at this time in the area of Anthropology.

Monday, December 04, 2006

New book about Omega-3 fatty acids

Here's a review in Nature of a new book on Omega-3 fatty acids:

The Queen of Fats: Why Omega-3s Were Removed from the Western Diet and What We Can Do to Replace Them
by Susan Allport
University of California Press: 2006. 232 pp. $22.50, £14.95
Locations of visitors to this page