The Audacious Epigone crunches the Pew Religion Survey and comes up with some more insights….

The Audacious Epigone crunches the Pew Religion Survey and comes up with some more insights….

Pathogen prevalence predicts human cross-cultural variability in individualism/collectivism (Open Access):

…We suggest that specific behavioural manifestations of collectivism (e.g. ethnocentrism, conformity) can inhibit the transmission of pathogens; and so we hypothesize that collectivism (compared with individualism) will more often characterize cultures in regions that have historically had higher prevalence of pathogens. Drawing on epidemiological data and the findings of worldwide cross-national surveys of individualism/collectivism, our results support this hypothesis: the regional prevalence of pathogens has a strong positive correlation with cultural indicators of collectivism and a strong negative correlation with individualism. The correlations remain significant even when controlling for potential confounding variables. These results help to explain the origin of a paradigmatic cross-cultural difference, and reveal previously undocumented consequences of pathogenic diseases on the variable nature of human societies.

The, r = -0.69 at p-value 0.001 and n = 68. You can find the raw data here. It would be cool to see trends within nations/societies. For example, variation in altitude.

Related: Toxoplasma gondii & human culture.

I saw this paper in Nature Genetics, Disruption of P2RY5, an orphan G protein-coupled receptor, underlies autosomal recessive woolly hair:

The genetic determinants of hair texture in humans are largely unknown. Several human syndromes exist in which woolly hair comprises a part of the phenotype; however, simple autosomal recessive inheritance of isolated woolly hair has only rarely been reported…In all cases, we discovered pathogenic mutations in P2RY5, which encodes a G protein-coupled receptor and is a nested gene residing within intron 17 of the retinoblastoma 1 (RB1) gene. P2RY5 is expressed in both Henle’s and Huxley’s layers of the inner root sheath of the hair follicle. Our findings indicate that disruption of P2RY5 underlies ARWH and, more broadly, uncover a new gene involved in determining hair texture in humans.

Disease loci can tell us a lot about the normal range of human variation; the blue-eye gene was originally implicated in a form of albinism. So I got curious and popped P2RY5 into Haplotter, which detects recent selection events. Here’s what I found….

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Parallel Selection on TRPV6 in Human Populations (Open Access):

…The selective footprints, however, are significantly differentiated between non-African populations and estimated to be younger than an ancestral population of non-Africans. The possibility of a single selection event occurring in an ancestral population of non-Africans was tested by simulations and rejected. The putatively-selected TRPV6 haplotype contains three candidate sites for functional differences, namely derived non-synonymous substitutions C157R, M378V and M681T. Potential functional differences between the ancestral and derived TRPV6 proteins were investigated by cloning the ancestral and derived forms, transfecting cell lines, and carrying out electrophysiology experiments via patch clamp analysis. No statistically-significant differences in biophysical channel function were found, although one property of the protein, namely Ca²⁺ dependent inactivation, may show functionally relevant differences between the ancestral and derived forms. Although the reason for selection on this locus remains elusive, this is the first demonstration of a widespread parallel selection event acting on standing genetic variation in humans, and highlights the utility of between population EHH statistics.

Jump to discussion:

A potential selective force that could result in parallel selection in different populations is agriculture. The independent development of agriculture in several different parts of the world within the past 11,000 years…including the Middle East (11,000 ybp), East Asia (9,000 ybp), the Americas (5,000-4000 ybp), and the New Guinea highlands (9,000-6,000 ybp), fits remarkably well with the demonstrated parallel selection on TRPV6 in the ancestors of Europeans and Asians, and potentially in the Americas and New Guinea as well. It may be that dietary changes related to the switch to agriculture underlie the selective event, or that selection on TRPV6 is related to resistance to a particular disease that became important with the increased population densities associated with agriculture.
As a simple test of this hypothesis, we included three hunter-gatherer groups from India in our genotyping of the three tagging SNPs in worldwide populations (Koragas, Mullukurunan, and Mullukurumba…however, all three populations were fixed for the derived, putatively-selected haplotype, suggesting that selection for this haplotype also occurred in the ancestors of these groups. While to the best of our knowledge these populations have always been hunter-gatherers, it is possible that they have reverted from an agricultural to a hunting-gathering lifestyle, as has been documented for other hunting-gathering groups…Genotyping of additional hunter-gatherer groups would therefore be desirable.

I would bet many Old World “hunter-gatherer” populations in close proximity to the Oikumene were driven there, or, gene flow has swamped out any “pure” original signature. In any case, the paper is basically talking about the process whereby extant genetic variation that was always around got selected due to changes in the exogenous pressures. So a switch to a new lifestyle. In contrast, the locus around LCT that’s swept in much of Eurasia seems to be derived from a relatively recent mutant.

How Skin Color Is Determined:

In 2005 researchers identified a gene called SLC24A5 as a key determinant of skin color. Rebecca Ginger and colleagues now confirm that the protein product of this gene (NCKX5) is an ion exchanger; it exchanges sodium for calcium across a membrane, regulated by potassium. But unlike other NCKX proteins, they found that NCKX5 is not present on the cell surface, but internally in a compartment known as the trans-Golgi network. This compartment is where new proteins and vesicles are processed, modified and sorted.

When the researchers knocked out NCKX5 in melanocytes (the skin cells that manufacture the melanin pigment), melanin production decreased dramatically. They also demonstrated that changing the ancestral amino acid (alanine) at position 111 to the European form associated with lighter skintone (threonine) reduced NCKX5’s exchanger activity.

Related: SLC24A5 and skin color.

Reading Power and Plenty: Trade, War, and the World Economy in the Second Millennium by by Ronald Findlay and Kevin H. O’Rourke. So far somewhat like A Farewell to Alms, except painted on a much broader palette. I’ve read The Moral Consequences of Economic Growth, and though I wasn’t convinced by all the specific examples the general thrust of that work makes sense. Nevertheless, I was still surprised when Findlay and O’Rourke connected the introduction of Champa rice strains and the cultural efflorescence of the Sung period. Say what? OK, this the logic, the new rice strains resulted in far greater productivity, and so China’s population doubled in about 200 years, from 50 to 100 million. This 200 year period can be thought of as a transient between stationary states around the Malthusian limit. Findlay & O’Rourke don’t focus much on the specific expressions of creativity during this period, but if you read much Chinese history you note that there was a lot of stuff going on during this period which set the tone for the next 1,000 years, from Neo-Confucianism to styles of landscape painting.

In the comments to my post, Why brown people are midgets, a reader pointed me to this paper, which tabulates and analyzes some data from the 1960s for males. There isn’t anything too surprising in the data set; Punjabis are tall compared to non-Punjabis, higher castes are taller than lower castes. There is a lot of unaccounted for variation. This was before Indian Shining, and the Green Revolution probably hadn’t sunk in yet (I wouldn’t be surprised if the between-state differences increased, while the between-caste differences decreased, in the past 40 years). So appropriate caveats. The one surprising thing is that being a Muslim was a variable that predicted more height! This is correcting for regional distribution. The reason it’s surprising is that Muslims are genetically no different from non-Muslims (e.g., in Uttar Pradesh the highest proportion of recent West Asian ancestry is 5% across the whole population) and tend to socially disadvantaged in India (i.e., they are a Backward Class). The only explanation I have is that Muslims are less likely to be vegetarian or have dietary taboos which constrain their nutritional choices. Tables below the fold….

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John Hawks has commentary on a new paper, A genome-wide signature of positive selection in ancient and recent invasive expansions of the honey bee Apis mellifera. John’s point is that evolutionary dynamics are evolutionary dynamics. I’m sure as a species which spans multiple continents and all the latitudes and longitudes we might be able to learn a bit about ourselves from examining other lineages of great geographic range.

Despite the fact that the mainstream media likes to write a lot of stories how religious revival in the United States one of the great unreported facts of the last 15 years is the rise of the proportion of Americans who are not affiliating with any religion. The reason this isn’t reported much is that it won’t sell that much copy; the irreligious by their nature don’t get that excited by irreligion. In contrast religious people want to read about how religion is on the rise. There will always be stories about how religion & science dovetail in the media because that sells magazines; the fact that 9 out of 10 National Academy of Science members are atheists or agnostics won’t sell magazines, and might even make scientists a little worried about the funding pipeline.

The US Religious Landscape Survey by Pew doesn’t come burdened by the need to satisfy the consumer market. From chapter 2:

The biggest gains due to changes in religious affiliation have been among those who say they are not affiliated with any particular religious group or tradition. Overall, 7.3% of the adult population says they were unaffiliated with any particular religion as a child. Today, however, 16.1% of adults say they are unaffiliated, a net increase of 8.8 percentage points. Sizeable numbers of those raised in all religions – from Catholicism to Protestantism to Judaism – are currently unaffiliated with any particular religion.

…

The unaffiliated group provides a good example of the high degree of religious movement that has taken place in the U.S. Overall, 3.9% of the adult population reports being raised without any particular religious affiliation but later affiliating with a religious group. However, more than three times as many people (12.7% of the adult population overall) were raised in a particular faith but have since become unaffiliated with any religious group.

Here are some breakdowns:

Percentage of Adults Entering and Leaving Each Group
	Childhood Religion	Entering Group	Leaving Group	Current Group
Atheist	0.5	+1.4	-0.3	1.6
Agnostic	<0.3	+2.3	-<0.3	2.4
Nothing in particular	6.6	+9.6	-4.1	12.1

But do note that not all unaffiliated people are atheists are agnostics, in fact, the majority are not. The Pew study notes that this unaffiliated group is divided between those who are secular (religious sentiments are not important) and those who are believers of some sort, if not affiliated (one could term these the “spiritual” segment). Below are some tables of interest from the Pew study.

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