Who were the ancestors of modern Europeans?

A mitochondrion (source). Is mitochondrial DNA selectively neutral?

Were Ice Age Europeans a dead end, like the Neanderthals before them? Did Middle Eastern farmers replace indigenous hunter-gatherers, just as Europeans would later replace native Indians in North America?

This debate has been raging back and forth for some time, but it has now entered a new phase with retrieval of mtDNA from ancient European skeletons. We can now genetically compare late hunter-gatherers with early farmers. We can now ask the question: Which of them were the ancestors of modern Europeans?

This kind of comparison has recently been made in Sweden, where farming replaced hunting/gathering/fishing some 5,000 years ago. This is the time depth for mtDNA retrieved from two burial sites: a farming community in Gökhem parish (one individual) and a hunter-gatherer community on the island of Gotland (three individuals). The results?

The Neolithic hunter-gatherers shared most alleles with northern Europeans, and the lowest allele sharing was with populations from southeastern Europe. In contrast, the Neolithic farmer shared the greatest fraction of alleles with southeastern European populations (Cypriots and Greeks) and showed a pattern of decreasing genetic similarity to populations from the northwest and northeast extremes of Europe (Skoglund etal., 2012)

The authors then went on to estimate the degree of admixture from Middle Eastern farmers in present-day Europeans:

We estimated that people of southern, central and northern Swedish descent are, on average, of 41 ± 8%, 36 ± 7%, and 31 ± 6% Neolithic farmer–related ancestry, respectively (±1 SE). Across Europe, this fraction decreases from 95 ± 13% in Sardinians to 52 ± 8% in the CEU population (individuals of northwestern European descent) and 11 ± 4% in Russians (Skoglund et al., 2012)

So, according to this study, northern Europeans are mainly descended from the hunter-gatherers of Ice Age Europe. But there is also substantial admixture from those Middle Eastern farmers—roughly a third of the present-day Swedish gene pool.

Is this the last word? No, the debate will surely continue. For one thing, the sample sizes are still small. For another, the replacement of hunter-gatherers by farmers may have played out differently in different places.

But there is a more fundamental objection. All of this assumes that we have a reliable yardstick for measuring admixture. For this to be so, mtDNA must not be influenced by natural selection. In particular, it must not be influenced by the change in selection pressures that occurs when hunting and gathering give way to farming. Is this assumption valid?

When we compare late hunter-gatherers with present-day Europeans, the main change to mtDNA is the loss of haplogroup U. Indeed, if this haplogroup had not declined to its current low levels, the above admixture estimates would be minimal.

Today, haplogroup U reaches high levels only among the Saami of Finland and the Mansi of northwestern Siberia, both of whom were hunter-gatherers until recently (Derbeneva et al, 2002). Did something about that lifestyle favor this haplogroup?

Balloux et al. (2009) have argued that some haplogroups create different trade-offs between thermogenesis and ATP synthesis. In particular, haplogroup U is associated with reduced sperm motility—an indication that the energy balance is shifted from producing ATP to producing heat:

The ATP that drives the sperm flagella is derived from the mitochondria located in the midpiece. Therefore, mutations in the mtDNA which increase or decrease ATP production will be reflected in increased or decreased sperm motility.

[…] Therefore, shifting the energy balance from primarily ATP production to increased heat production could explain the lower sperm motility and the predilection of these sublineages U to reside in colder climates and their northern distribution. (Montiel-Sosa et al., 2006)

Being nomadic, hunter-gatherers spent more time in the cold, especially when sleeping in temporary shelters. Farming brought more sedentary living and a generally warmer sleeping environment. There would thus have been weaker natural selection for genetic variants, like haplogroup U, that maintain a higher body temperature at the expense of lower ATP production.

This hypothesis is testable. If haplogroup U disappeared because Middle Eastern farmers partially replaced native hunter-gatherers, this genetic change should largely coincide with the time boundary between late hunter-gatherers and early farmers. If this haplogroup disappeared through natural selection, the change should have occurred gradually over a longer period.

The second scenario seems closer to the truth. In a study of 92 Danish human remains that ranged in time from the Mesolithic to the Middle Ages, Melchior et al. (2010) found that high incidences of haplogroup U persisted long after the advent of farming and apparently as late as the Early Iron Age.

References

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.

Derbeneva, O.A., E.B. Starikovskaya, D.C. Wallace, & R.I. Sukernik. (2002). Traces of early Eurasians in the Mansi of Northwest Siberia revealed by mitochondrial DNA analysis, Am. J. Hum. Genet. 70:1009–1014.

Melchior, L., N. Lynnerup, H.R. Siegismund, T. Kivisild, J. Dissing. (2010). Genetic diversity among ancient Nordic populations, PLoS ONE, 5(7): e11898

Montiel-Sosa, F., E. Ruiz-Pesini, J.A. Enríquez, A. Marcuello, C. Díez-Sánchez, J. Montoya, D.C. Wallace, & M.J. López-Pérez. (2006). Differences of sperm motility in mitochondrial DNA haplogroup U sublineages, Gene, 368, 21–27.

Skoglund, P., H. Malmström, M. Raghavan, J. Storå, P. Hall,  E. Willerslev, M.T. Gilbert, A. Götherström, & M. Jakobsson. (2012). Origins and genetic legacy of Neolithic farmers and hunter-gatherers in Europe, Science, 336, 466-469.

Vitamin D metabolism and northern native peoples

Early winter afternoon in Tromso, Norway (source). There is little or no solar UV for vitamin D synthesis at high northern latitudes. Humans have had to adapt accordingly.

I’ve published another article on vitamin D metabolism and northern Native peoples. It’s actually a reply to a letter criticizing my initial article.

A few extracts:

We know that natural selection can alter the way the human body synthesises, transports and uses this vitamin. We also know that the relevant selection pressures (from solar UV and skin color) vary from one human population to the next. So it is not necessarily unhealthy for a population to have low blood levels of vitamin D. The underlying metabolism may simply be different.

[…] This has been especially true at high northern latitudes, where solar UV is too weak for synthesis in the skin. An alternative is to consume fatty ocean fish, but this food source was formerly available only in coastal regions. The interior of Alaska and northern Canada had few natural sources of vitamin D.

Over time, northern Natives should have adapted to this situation through natural selection. And they had time: some 15,000 years in Arctic North America and longer still if we include their remote ancestors in Beringia and northern Eurasia. Natural selection also had many possible ways to make their bodies less dependent on vitamin D: receptors that bind this molecule more strongly; greater storage in the body and better transport in the bloodstream to target tissues; increased uptake of calcium and phosphorus through alternate metabolic pathways, etc. Indeed, the Inuit show high uptake of calcium despite low levels of vitamin D.

Comments are welcome.

References

Frost, P. (2012). Reply to W.B. Grant ‘Re: Vitamin D deficiency among northern Native Peoples’International Journal of Circumpolar Health,71, 18435 - DOI: 10.3402/ijch.v71i0.18435 http://www.circumpolarhealthjournal.net/index.php/ijch/article/view/18435/pdf_1

East Asia at the crossroads

Is Japan dying? (Source: PBT Consulting)

Today, East Asia is widely acclaimed for decade upon decade of economic success. Yet this success rests on a very fragile foundation—an aging population with the world’s lowest fertility. This situation is viewed with surprising indifference by East Asians and Westerners alike. As with so many other things, we prefer to see tomorrow through yesterday’s eyes.

Yet tomorrow is already here. Outside the big cities, East Asia looks more and more like an old folks home. This is especially so in Japan, where the median age is now 45. But populations are also graying throughout South Korea, Taiwan, Singapore, and most of China.

Nature abhors a vacuum. There will be pressures from within and without to open the doors to mass immigration—all the more so because of the mounting influence of globalist thinking. To date, most of East Asia has resisted these pressures, probably because national identity is still relatively strong and the elites understand the consequences.

But the elites are changing. They’re following the same trend towards post-nationalism and globalism that is occurring in the West. As they identify less and less with their respective nation states, they’ll follow more and more their own interests—and those interests won’t be the same as those of the mass of the population.

Just as globalization redistributes wealth from higher-wage countries to lower-wage countries, it also redistributes wealth from the workers to the owners of capital. If your money comes from your own work in your own country, you’ll benefit much less than someone whose income has a more global reach. In fact, you’ll be a net loser.

So, as East Asia’s elites lose national consciousness, they’re going to feel more and more encumbered by their nation states. And they’re going to act on their feelings. This is already happening in South Korea, and Taiwan will probably follow suit. It’s probably no coincidence that both countries have strong political, cultural, and ideological links with the United States.

What about the rest of East Asia? National consciousness seems to be strongest in China and, especially, North Korea. Ironically, both countries once saw themselves as proponents of internationalism. Yet, by submitting everything to State control, they unwittingly created a very conservative culture. Today, national feeling is better preserved in the former Communist bloc than in the West, as are many other traditional life ways.

In China, the decline of Marxist-Leninism has left a vacuum that is being filled in part by Western post-nationalism and in part by a resurgence of national feeling. The second trend seems to have grown stronger in recent years. One reason is that the elites are increasingly wary of the West, especially the United States. The other reason is that China can now produce its own high-quality movies, TV programs, and popular entertainment. This locally based cultural production gives a larger place to nationalistic and historical themes than is the case with cultural products imported from the West.

East Asia is thus being pulled in opposite directions by two irreconcilable ideologies. On the one hand, an elite-driven globalism is increasingly hostile to the nation state and even to the very existence of nations. On the other, an anti-globalist reaction is developing to defend the demographic status quo. There seems to be little room for compromise.

The next East Asian domino

McDonald’s in Taipei. By the 1990s, Taiwan had already become a “post-nation” (source)

East Asia has long been bucking the trend toward globalization. Its countries have become major players in the global marketplace, while jealously guarding their cultural specificity and national character.

But East Asia is now getting with the program. South Korea in particular has embraced the view that all factors of production, including its own people, should submit to the logic of globalization. Although the inflow of migrant labor is supposed to be a response to economic growth, there seems to be little relationship between the two. South Korea has actually had slower economic growth since the Asian crisis of the late 1990s, and yet these same years have seen a steady rise in immigration.

As Kang (2010) notes:

Economic growth in South Korea demanded a change to the solid mono-ethnic labour market, previously exclusive of other races. Migrant workers replaced departing Koreans at small and middle-sized factories, receiving low wages and doing intensive labour, mostly coming as “industrial trainees” at the beginning. But from around 1997, the so-called Asian economic crisis has left them in terrible conditions, being categorized as illegal and undocumented, without any official countermeasures from the Korean government. They were frequently arrested and deported from then. Nevertheless the number of foreign residents is increasing every year, except for 1998 […]

None of this should be surprising. In a global marketplace, there is a strong incentive to cut the cost of labor, either by outsourcing production or by insourcing workers. This two-way process will continue until wage rates are more or less the same throughout the world. So it doesn’t matter how low the wages are in labor-importing countries. What matters is whether the wages are even lower in labor-exporting countries. Such is the logic of globalization.

South Korea’s example is now being followed by another East Asian country—Taiwan. Here too, history seems to have paved the way for globalization. Before 1945, the Taiwanese were citizens of the Japanese Empire, even though most were culturally Chinese. They were thus already thinking of citizenship in ‘propositional’ terms, i.e., as adherence to a particular political system. This tendency was reinforced when the Chinese civil war ended and Taiwan became a place of refuge for the defeated Nationalists. Taiwanese identity thus became constructed in ideological terms … in opposition to the Communists on the mainland.

At the same time, Taiwan took in large numbers of refugees from different parts of Mainland China with different dialects and traditions of their own—an estimated 1 to 1.5 million. This experience would help prepare the Taiwanese for the current wave of non-Chinese immigrants:

Even before the advent of transnational capitalism, there has been steady influx of “outsiders” into postwar Taiwanese society, if one not only includes the gradual absorption of overseas Chinese (including from Hong Kong) but also the marginal existence of long resident foreigners (many of whom have married local spouses and settled into long term employment). To this, one can add in recent years the massive influx of contract laborers (Filipino maids, Thai construction workers, illegal PRC immigrants, expatriate businessmen and technical experts, etc.) as well as increased numbers of Chinese abroad lured back by super-salary jobs and Chinese youth raised abroad who have “returned” to exploit the growing niche of professional work requiring English language fluency. All have in very different ways contributed to an increasingly diversified and transnational local Taiwanese economy, albeit accommodated within an ongoing stratified system. (Chun, 2001)

Another predisposing factor has been Taiwan’s special relationship with its main protector, the United States. Many of its political and economic leaders are graduates of American colleges and universities. On coming home, they propagate the same discourse that they earlier learned in the U.S.:

Multiculturalism is now “in”. As a term of official discourse, the advent of “multiculturalism” (duoyuan zhuyi) seems to be a recent phenomenon that has culminated with, among other things, the election of the first President from the Taiwan independence minded opposition Democratic Progressive Party (DPP). (Chun, 2001)

School textbooks are being rewritten to emphasize this new perspective:

Narrative of immigration plays a pivotal role in the multiculturalism discourse. In a school textbook entitled 'Understanding Taiwan’, Taiwan enters the stage as such: ‘Taiwan is an immigrant society, from the Stone Age to the present, people coming here across many different times and places. Before the largest number of Han arrived on Taiwan, Aborigines were already here’ (cited by Harrison: 2006: 195). It also teaches students that Taiwan’s history is characterised by a) multiple cultures; b) internationalisation; c) prosperous foreign trade; d) bravery, adventurousness, and endurance (Cheng, 2008)

The above predisposing factors have thus allowed a deeper penetration of globalist thinking than in, say, Japan. Nonetheless, globalism is gaining dominance throughout the world. It is perhaps an inevitable stage of capitalism where the business community has freed itself from the nation state and pursues solely its own self-interest:

Foreign labor in general is not a new phenomenon to global capitalism, which was in fact responsible for orchestrating the first major waves of ethnic migration in human history. However, the role of foreign labor has clearly been transformed by the current phase of transnational capitalism, characterized by disorganized flows of capital and labor, borderless economies and the withering away of nationalist protectionism of various sorts, not to mention the most recent evolution of supra-national economic zones, such as EEC and NAFTA. (Chun, 2001)

Yet East Asia is one region where we may see pushback. At first thought, this prospect seems unlikely. The local political and economic elites have converted massively to globalism. Moreover, there doesn’t seem to be any possible ideology of opposition—other than communism, which is widely discredited even in Mainland China. To a large extent, this is what we see elsewhere: globalism has co-opted the entire political spectrum from the left to the right.

Chun (2001) nonetheless predicts that a movement of opposition will develop in Taiwan, ironically out of multicultural discourse, specifically its indigenist component. Although indigenism has primarily served to defend the native Austronesian tribes of eastern Taiwan, it is now also being used to portray the Taiwanese as an indigenous nation, in opposition to the People’s Republic of China. At a time when the PRC has embraced the global market economy, the Taiwanese political leadership is turning towards indigenist rhetoric as the sole remaining means of legitimizing their country’s existence.

According to Chun (2001), Taiwan was already showing all the signs of a “post-nation” by the 1990s: social atomization, disinterest in cultural and kinship affiliation, emergence of the market as the main organizing principle of society, etc. Multicultural/indigenist discourse can do nothing to push Taiwan farther in that direction, but it can do much to reawaken national consciousness. “At a deeper level, both (cosmopolitan) "transnationalism" and (indigenous) "multiculturalism" are in my opinion largely incompatible and mask an imminent future crisis” (Chun, 2001).

Globalism today enjoys a predominance in East Asia that is both monolithic and superficial. Although it has a stronger hold on the elites and on the general population than in the West, this adherence has no deep roots in the underlying culture. In the West, by contrast, globalism has been grafted onto a pre-existing tradition that is much more compatible. There is notably Christianity and its commitment to mission work throughout the world. There is also the emotional heritage of imperialism and colonialism. Although the West lost its colonies more than a half-century ago, many Westerners still feel connected to them and responsible for them.

This cultural substrate is largely, if not wholly, absent in East Asia. When, and if, pushback begins there, resistance will likely collapse after initially strong resistance.

References

Cheng, I. (2008). Immigrants and National Identity of Taiwan: A Preliminary Study on Multiculturalism Practice
http://www.soas.ac.uk/taiwanstudies/eats/eats2008/file43182.pdf

Chun, A. (2001). The coming crisis of multiculturalism in “transnational” Taiwan, New Cultural Formations in an Era of Transnational Globalization, Academia Sinica, Taiwan, Oct 6-7, 2001

Kang, S.W. (2010). Multicultural education and the rights to education of migrant children in South Korea, Educational Review, 62(3), 287-300.

Reflections on the revolution in South Korea

Cartoon lampooning the traffic in mail-order brides (source). About 40% of married men in rural South Korea have wives of foreign origin.

Until recently, South Korea had no ethnic minorities. Nor did it have a history of being a colonial power. While slavery did exist, the slaves were not from elsewhere.

Today, however, the country is in the throes of demographic change. In the late 1980s, it began to open its borders to immigrants, initially diaspora Koreans from Manchuria, Uzbekistan, and other sources. Since the mid-1990s, the zone of recruitment has been extended to the Philippines, Vietnam, Indonesia, Bangladesh, Sri Lanka, Pakistan, and even countries as far afield as Nigeria (Kim, 2004).

How much has immigration changed South Korea? In 2010, foreigners officially made up 2.6% of the population, and this proportion is set to reach 9.2% by 2050 (Park, 2011; Yoon et al., 2008). Like all statistics, these figures should be viewed with caution. For instance, a third of all foreigners may be diaspora Koreans, whose cultural impact is much less than that of other immigrants.

On the other hand, the official statistics greatly understate the impact of immigration in at least three ways. First, the term ‘foreigner’ doesn’t mean ‘foreign-born.’ It refers only to those residents who haven’t received South Korean citizenship yet. When a foreigner becomes a citizen, he or she disappears from the statistics and is deemed to be sociologically the same as any other Korean. No statistics are kept on ethnic origin.

Second, the official statistics exclude Korean-born children of foreigners. This group is far from negligible, especially in the case of mail-order brides from southeast Asia and elsewhere:

In 2010, 10 percent of married couples were interracial, an increase from four percent in 2000, according to Statistics Korea. The prevalence of interracial couples is dramatically higher in rural areas. About 40 percent of married couples in Korean rural areas are interracial couples; it is projected that biracial children will represent about 50 percent of rural children in 2020 (Park, 2011).

These children are most often born to mothers from countries with higher fertility, and such countries also differ more from Korea in terms of culture, religion, and ethnic makeup.

Third, the official statistics exclude illegal immigrants, who are estimated to make up half the total immigration intake (Moon, 2010).

So how much is immigration changing South Korea? There is no exact answer, but an exact one may be unnecessary. When American-style open borders combine with East Asian fertility (1.2 children per woman in 2010), the future is a foregone conclusion.

How will this future play out? Will South Korea avoid the problems of ethnic conflict and discrimination that other countries have experienced? There are already growing concerns. Lim (2010) deplores the high dropout rate among biracial children and suggests they “face a future as the country’s permanent, racialized underclass” (Lim, 2011).

Poor academic performance does seem to be a problem among Korean children with at least one foreign-born parent. The cause is widely said to be social exclusion.

Because their mothers have difficulty in speaking and writing Korean, these children may be making slow progress in language development in comparison to the Korean children. They then are also likely to be seen as having learning difficulties and as being less adapted to school life with friends due to such delayed development in language and cultural understanding in the home (Sul, G.-S. Han, and J.-R. Lee 2003; Oh 2005; Cho 2006). As a consequence, the children confront difficulties at school, often being viewed as learning-disabled. (Kang, 2010)

The kind of “learning-deficiency” treatment leads them to drop out of school and discourages their enrolment at higher levels of schooling. The drop-out rate among mixed-blood youths is estimated at 9.4% in elementary schools and 17.5% at the secondary level, compared with less than 3% among ordinary Korean youths (Docuinfor 2004). These youngsters may be alienated from mainstream society, feeling prejudice and discrimination, and frustration about the lack of positive future prospects. (Kang, 2010)

In short, it is argued that these children fare worse in school because they improperly learn the Korean language at home. This in turn leads to poor social skills and rejection by peers.

If the above explanation is correct, these children should do worse in subjects that demand much social interaction and language use. Conversely, they should do better in subjects that require abstract skills, like mathematics, or memorization of names and dates, like social studies. This is, in fact, the pattern we see among children of East Asian immigrants in North America.

But this is not really the pattern we see among children born in South Korea to non-Korean mothers:

Their favourite subjects are music/painting/physical education (42.6%), while they dislike math (38.1%), social studies (19.2%) and Korean (12.7%) (Kang, 2010).

The learning deficit seems to be strongest in those subjects that require the most abstraction and memorization. These learning skills, however, are the pillars of Korean education.

It will thus not be enough to mandate social inclusion. The educational system itself will have to change:

Traditional forms of education which reflect little more than “cramming” knowledge or fact are inadequate and counterproductive for children with different cultural needs (Kang, 2010).

Should “cramming” be abandoned in the new Korea? It depends on the kind of new Korea one wants. Keep in mind that the country has few natural resources. Its most important resource is its people, specifically a workforce that can “cram” knowledge. To the extent that it loses this resource, it will become poorer—and probably less interesting for immigrants.

References

Kang, S.W. (2010). Multicultural education and the rights to education of migrant children in South Korea, Educational Review, 62(3), 287-300

Kim, W-B. (2004). Migration of foreign workers into South Korea: from periphery to semi-periphery in the global labor market, Asian Survey, 44, 316-335.

Lim, F.J. (2011). Korea’s multicultural future? New Leaders Forum
http://the-diplomat.com/new-leaders-forum/2011/07/20/south-koreas-multiethnic-future/

Moon, S. (2010). Multicultural and Global Citizenship in the Transnational Age: The Case of South Korea, International Journal of Multicultural Education, 12, 1-15.

Park, S. (2011). Korean Multiculturalism and the Marriage Squeeze, Contexts, 10, 64-65.

Yoon, I-J.,Y-H. Song, & Y-J. Bae. (2008). South Koreans' Attitudes toward Foreigners, Minorities and Multiculturalism, Paper prepared for presentation at the annual meeting of the American Sociological Association, Boston, MA from August 1-4, 2008.

Dark coloration and male aggressiveness: Is there a link?

Red-winged blackbird (source). Is dark coloration directly linked to male aggressiveness?

For the past thirty years, psychologist Philippe Rushton has been using life history theory to explain human differences in many areas: IQ, sexual development, parental investment, mating system, time orientation, etc. Initially, he saw skin color as being incidental. In recent years, however, he has come around to the view that differences in skin color directly mediate these differences in life history:

The hypothesis that skin color is a genetic correlate of IQ was endorsed by Jensen (2006) who suggested that pleiotropy (genes having more than one effect) may underlie the relationship. Skin color became of greater theoretical interest after Ducrest, Keller, and Roulin (2008) reviewed the literature and reported that in 20 wild vertebrate species, darker individuals were more aggressive, sexually active, and resistant to stress than lighter individuals. Studied were three mammal species (African lion, soay sheep, and white-tailed deer), four fish species (mosquito fish, guppy, green swordtail, and Arctic char), four reptile species (asp viper, adder, fence lizard, and spiny lizard), one amphibian species (spadefoot toad) and 36 bird species. Darker individuals also tended to have a larger body mass and greater energy and physical activity such as grooming. Ducrest et al. (2008) confirmed the naturalistic observations using experimental studies such as the administration of melanocortins and the fostering of infants to non-biological parents. For example, the fostering studies found darker maned male lions are more aggressive and sexually more active, and darker barn owls mount stronger immune responses when their biological parents are darker, even though they had been raised by lighter foster parents. (Templer & Rushton, 2011)

This hypothesis is not a perfect fit for humans, as Rushton himself noted in an earlier study on human populations and behavioral differences: “We found the relationship between crime and IQ held (r=−0.35; Pb0.01), although the one between crime and skin color did not (ns). […] the East Asian countries had very low rates of crime but not the lightest skin color” (Rushton & Templer, 2009).

In humans, many things vary with latitude, and not just skin color. One of them is the means of sustenance, which in turn impacts parental investment, mating system, and male-male rivalry. In the tropics, for example, we see the following cascade of effects:

1. Year-round tropical agriculture enables women to provide for themselves and their children with little male assistance.

2. This greater female reproductive autonomy lowers the cost of polygyny for men. More men can afford to have second wives.

3. Because more men are competing for fewer available women, there is stronger selection for males with higher testosterone levels, more robust body build, and greater ability to fight off rivals.

It is hard to see how this cascade of effects could apply to nonhumans. Guppies, for instance, have not discovered farming. Nor is their coloration a climatic adaptation. It serves as a visual signal and not as a UV shield, as is the case with most of the other animals that Templer and Rushton cite.

Clearly, a cross-species correlation does exist between darker coloration and male aggressiveness. But there is an alternate explanation. Whatever the species, individuals are usually born with little or no pigment. Lighter coloration thus becomes associated with vulnerability and a need for parental care and protection. In contradistinction to this sign stimulus, adult males tend to evolve a darker coloration, especially in a context of intense male-male rivalry. This tendency was noted by Guthrie (1970):

Light skin seems to be more paedomorphic, since individuals of all races tend to darken with age. Even in the gorilla, the most heavily pigmented of the hominoids, the young are born with very little pigment. […] Thus, a lighter colored individual may present a less threatening, more juvenile image.

Our own species likewise shows analogous age and sex differences in skin pigmentation, as seen in a strong cross-cultural trend to associate darker skin with men and lighter skin with infants and women (Frost, 2011).

This mental association may influence human mate choice, especially under conditions of intense mate competition. Given that mate competition varies latitudinally among human populations, as described above, could it be that latitudinal differences in skin color result not only from selection for UV protection but also from sexual selection?

In humans, the polygyny rate does in fact significantly correlate with darkness of skin color (Manning et al., 2004). This correlation seems to hold up even if we control for latitude. In sub-Saharan Africa, high-polygyny agriculturalists are visibly darker than low-polygyny hunter-gatherers, i.e., Khoisans, pygmies, although both are equally indigenous (Bourguignon & Greenbaum, 1973, pp. 171-175; Cavalli-Sforza, 1986a; Cavalli-Sforza, 1986b; Weiner et al, 1964). Because year-round agriculture makes women more self-sufficient and polygyny less costly, fewer women remain unmated and men are less able to translate their mate-choice criteria into actual mate choice. Such criteria include a preference, widely attested in the African ethnographic literature, for so-called 'red' or 'yellow' women (van den Berghe & Frost, 1986). Less mate choice means weaker sexual selection for light skin in women and, hence, less counterbalancing of natural selection for dark skin in either sex to protect against sunburn and skin cancer (Aoki, 2002; Frost, 1994; Frost, 2007; Frost, 2008).

A higher polygyny rate might also, correspondingly, lead to stronger sexual selection for darker-skinned men, either because women tend to prefer them, or defer to them, or because such men can more easily intimidate rivals in a context of intense mate competition.

References

Aoki, K. (2002). Sexual selection as a cause of human skin colour variation: Darwin’s hypothesis revisited. Annals of Human Biology, 29, 589-608.

Bourguignon, E. & L.S. Greenbaum. (1973). Diversity and Homogeneity in World Societies, HRAF Press.

Cavalli-Sforza, L.L. (1986a). Demographic data. In Cavalli-Sforza, L.L. (ed.). African Pygmies, pp. 23-44. Academic Press.

Cavalli-Sforza, L.L. (1986b). Anthropometric data. In Cavalli-Sforza, L.L. (ed.). African Pygmies, pp. 81-93. Academic Press.

Ducrest, A., Keller, L., & Roulin, A. (2008). Pleiotropy in the melanocortin system, coloration and behavioural syndromes. Trends in Ecology and Evolution, 23, 502-510.

Frost, P. (2011). Hue and luminosity of human skin: a visual cue for gender recognition and other mental tasks, Human Ethology Bulletin, 26(2), 25-34. http://media.anthro.univie.ac.at/ISHE/index.php/bulletin/bulletin-contents

Frost, P. (2008). Sexual selection and human geographic variation, Special Issue: Proceedings of the 2nd Annual Meeting of the NorthEastern Evolutionary Psychology Society. Journal of Social, Evolutionary, and Cultural Psychology, 2(4),169-191. http://137.140.1.71/jsec/articles/volume2/issue4/NEEPSfrost.pdf

Frost, P. (2007). Comment on Human skin-color sexual dimorphism: A test of the sexual selection hypothesis, American Journal of Physical Anthropology, 133, 779-781.

Frost, P. (1994). Geographic distribution of human skin colour: a selective compromise between natural selection and sexual selection? Human Evolution, 9, 141-153.

Guthrie, R.D. (1970). Evolution of human threat display organs, Evolutionary Biology, 4, 257-302

Jensen, A. R. (2006). Comments on correlation of IQ with skin color and geographic–demographic variables. Intelligence, 34, 128−131.

Manning, J.T., P.E. Bundred, & F.M. Mather. (2004). Second to fourth digit ratio, sexual selection, and skin colour. Evolution and Human Behavior, 25, 38-50.

Rushton, J. P., & Templer, D. I. (2009). National differences in intelligence, crime, income, and skin color. Intelligence, 37, 341-346.

Templer, D. I., & Rushton, J. P. (2011). IQ, skin color, crime, HIV/AIDS, and income in 50 U.S. states. Intelligence, 39(20), 437-442.

van den Berghe, P.L., & P. Frost. (1986). Skin color preference, sexual dimorphism and sexual selection: A case of gene-culture co-evolution? Ethnic and Racial Studies, 9, 87-113.

Weiner, J.S., G.A. Harrison, R. Singer, R. Harris, & W. Jopp. (1964). Skin colour in southern Africa. Human Biology, 36, 294-307.

The 'monkey people' we once knew

Remains of archaic hominins from southwest China (Curnoe et al, 2012). They were around when villages and towns were arising in the Middle East.

Recent findings have confirmed the ‘Out of Africa’ model of human origins, but only in part. The model diverges from actual prehistory on two main points. One is that modern humans picked up archaic admixture as they spread out of Africa and into Eurasia. Thus, modern Eurasians have 1-4% Neanderthal admixture, and Melanesians an additional 4-6% from the mysterious Denisovans (Reich et al, 2011). As for modern sub-Saharan Africans, they seem to be the most admixed of all. About 2% of their gene pool comes from a population close to Homo erectus and a further 13% from a population probably related to the Skhul-Qafzeh hominins (Hammer et al., 2011; Watson et al., 1997).

And the second point? It appears that modern humans didn’t immediately replace archaic hominins, at least not everywhere. Some of the latter held out in different places of refuge until the Holocene, and perhaps even later. At a time when villages and towns were arising in the Middle East, archaic hominins continued to hold out in western and southern Africa (Harvati et al., 2011; Stringer, 2011).

Now, we have evidence of another refuge area. Southwest China has yielded archaic cranial remains that date to ~14.3-11.5 thousand years ago. The remains actually show a mixture of archaic and modern traits, reminiscent of the Skhul-Qafzeh hominins of the Levant (120,000 – 80,000 BP) and other ‘almost moderns’ from North Africa.

Who were they? The authors offer two explanations:

Our analysis suggests two plausible explanations for the morphology sampled at Longlin Cave and Maludong. First, it may represent a late-surviving archaic population, perhaps paralleling the situation seen in North Africa as indicated by remains from Dar-es-Soltane and Temara, and maybe also in southern China at Zhirendong. Alternatively, East Asia may have been colonised during multiple waves during the Pleistocene, with the Longlin-Maludong morphology possibly reflecting deep population substructure in Africa prior to modern humans dispersing into Eurasia (Curnoe et al., 2012).

The two explanations aren’t that far apart. Different authors have alternately described the Skhul-Qafzeh remains as either late archaic or early modern. In the case of the Chinese remains, an obvious candidate would be the Denisovans, an archaic population that inhabited East Asia around the time that Neanderthals inhabited Europe and central Asia. But the authors evoke this possibility only in passing:

DNA extracted from a >50 ka hominin fossil from Denisova Cave in Central Asia belonging within the Neandertal lineage shares features exclusively with Aboriginal Southeast Asians and Australasians. This has been interpreted as: 1) evidence for interbreeding between the ‘Denisovans’ and the earliest modern humans to colonise the region; and 2) implying occupation of Southeast Asia by this archaic population during the Upper Pleistocene.

In fact, we have good evidence that Denisovans were present in Southeast Asia. Reich et al. (2011) found Denisovan admixture in some but not all of the oldest indigenous peoples of Southeast Asia. Such admixture was present in Aboriginal Australians, New Guineans, and a Negrito people from the Philippines. It was absent, however, in Negrito groups farther west. The authors thus concluded:

Our finding that descendants of the earliest inhabitants of Southeast Asia do not all harbor Denisova admixture is inconsistent with a history in which the Denisova interbreeding occurred in mainland Asia and then spread over Southeast Asia, leading to all its earliest modern human inhabitants. Instead, the data can be most parsimoniously explained if the Denisova gene flow occurred in Southeast Asia itself. Thus, archaic Denisovans must have lived over an extraordinarily broad geographic and ecological range, from Siberia to tropical Asia.

If the Denisovans lingered on into historic times, the same might be true for other archaic groups, like the Neanderthals in Europe. Perhaps those stories about hairy wild men were not pure imagination.

Deusen (2001) mentions that the Tungus peoples of far eastern Siberia remember the existence of ‘monkey people’ in their region. One folk-tale describes how these monkey people abducted a man:

So the older sister took the shaman's drum. She started to sing and then said, "Brother, when you go hunting in the taiga tomorrow, you're going to meet two people. Check out their breasts, and then marry them."

The next day, he woke up and set out to go hunting. He walked and walked and came to a hill, a mountain. There were big rocks. He looked up, and then went on. Suddenly he saw two people sitting there. He approached and at that time the ties on his skis broke.

He came up to those people and felt their breasts and they were women. And they took him along with them.

At home time went by. A day passed and another, and still he was gone. Many days went by. And then the younger sister said, "Sister, you made this happen. Now you bring him back. Those two monkeys in the mountain came and took him away and now they are keeping him in the mountains, sucking his blood. He's become just skin and bones."

… So the younger sister sang and drummed, flying to her spirits, but she couldn't get there. She tried a second time and still didn't have the strength. The third time she gathered all her strength and flew to those rocks. She took her brother and dragged him out of there. He flew, looking thin as a shirt. They got him back and healed him. And that's how the younger sister brought her brother back from those monkeys.

… So that's it about the monkeys. They lived in the rocks and when they rolled back and forth, they called, "Tsyoo, tsyoo, papandasyoo!!" (Deusen 2001:126-128)

References

Abi-Rached L, Jobin MJ, Kulkarni S, McWhinnie A, Dalva K, et al. (2011). The shaping of modern human immune systems by multiregional admixture with archaic humans. Science, 334, 89–94.

Curnoe D, Xueping J, Herries AIR, Kanning B, Taçon PSC, et al. (2012). Human Remains from the Pleistocene-Holocene Transition of Southwest China Suggest a Complex Evolutionary History for East Asians. PLoS ONE 7(3): e31918. doi:10.1371/journal.pone.0031918
http://www.plosone.org/article/info%3Adoi%2F10.1371%2Fjournal.pone.0031918

Deusen, K.V. (2001). The Flying Tiger. Women Shamans and Storytellers of the Amur. Montreal: McGill-Queen's University Press.

Hammer, M.F., A.E. Woerner, F.L. Mendez, J.C. Watkins, and J.D. Wall. (2011). Genetic evidence for archaic admixture in Africa, Proceedings of the National Academy of Science (USA), 108, 15123-15128, www.pnas.org/cgi/doi/10.1073/pnas.1109300108

Harvati, K., C. Stringer, R. Grün, M. Aubert, P. Allsworth-Jones, C.A. Folorunso. (2011). The Later Stone Age Calvaria from Iwo Eleru, Nigeria: Morphology and Chronology. PLoS ONE 6(9): e24024. doi:10.1371/journal.pone.0024024
http://www.plosone.org/article/info%3Adoi%2F10.1371%2Fjournal.pone.0024024

Reich D, Green RE, Kircher M, Krause J, Patterson N, et al. (2010). Genetic history of an archaic hominin group from Denisova Cave in Siberia. Nature, 468, 1053–1060.

Reich D, Patterson N, Kircher M, Delfin F, Nandineni MR, et al. (2011). Denisova Admixture and the First Modern Human Dispersals into Southeast Asia and Oceania. Am J Hum Genet, 89, 516–528.
http://www.cell.com/AJHG/retrieve/pii/S0002929711003958

Stringer, C. (2011). The chronological and evolutionary position of the Broken Hill cranium. American Journal of Physical Anthropology, 144(supp. 52), 287

Watson, E., P. Forster, M. Richards, and H-J. Bandelt. (1997). Mitochondrial footprints of human expansions in Africa, American Journal of Human Genetics, 61, 691-704. 0024024
http://www.plosone.org/article/info%3Adoi%2F10.1371%2Fjournal.pone.0024024