The people before the First Nations

Aeta woman (Philippines) – Wikipedia (Ken Llio)

Modern humans pushed out of Africa along two routes: a northern one through the Levant and into Europe and a southern one along the Indian Ocean coast and eventually into New Guinea and Australia. The southern route is said to have had two waves: an earlier one between 62,000 and 75,000 years ago that was ancestral to present-day Australian Aborigines and a later one between 25,000 and 38,000 years ago that was ancestral to present-day Negrito groups in Southeast Asia: the Andaman Islanders, the Semang of the Malayan Peninsula, and the Aeta of the Philippines, although these groups would have intermixed with the population already present from the first wave (Rasmussen et al. 2011; Reyes-Centeno et al. 2014).

Did this southern route end in Southeast Asia or did it swing north along the Pacific coast? We know that the Philippines was once inhabited by Negritos—the country still has over thirty such groups. In addition, there have been claims that a Negrito group used to live on Taiwan. In the early 20th century, the anthropologist Rolange Dixon argued that a Negrito population once occupied the whole of the South, Southeast, and East Asian littoral:

At this time the southern and eastern borderlands, from India around to Kamchatka, seem to have been occupied in the main by a dolichocephalic, dark-skinned, Negroid population which was a blend in varying proportions of the Proto-Australoid and Proto-Negroid types. There is some evidence which leads us to believe that this Negroid population extended farther westward than India, along the shores of the Persian Gulf and the southern coast of Arabia, so being continuous with the great area held by similar peoples in Africa. (Dixon 1923, p. 243)

In the late 20th century, interest declined in Negritos and their place in human prehistory, partly because anthropologists were increasingly taking an ahistorical approach hunter-gatherers and shunning anything that smacked of racial or evolutionary thinking. Though a student of Franz Boas, Dixon studied anthropology (1897-1906) at a time when Boas believed not only in the existence of human races but also in psychological differences between them, albeit in a statistical sense (Frost 2014, Frost 2015). Furthermore, genetic studies in the late 20th century seemed to show that different Negrito groups had little in common with each other. Clearly, Negritos are a very ancient population, and the time to the most recent ancestor for all of them is greater than it is for, say, present-day Europeans and present-day East Asians. They still look similar to each other only because they remained under similar climatic and cultural conditions.

Recent years have seen a renewal of interest in Negritos. Mitochondrial DNA studies have shown that they are indeed the remnants of a southern "Out of Africa" route, together with New Guineans and Australian Aborigines (Reyes-Centeno et al. 2014; Stoneking and Delfin 2010; Thangaraj et al. 2005). Of particular interest is the discovery of significant admixture from these peoples in Amerindians from Amazonia and the Central Brazilian Plateau (Skoglund et al. 2015). This admixture seems to be very old:

The genetic data allow us to say with confidence that Population Y ancestry arrived south of the ice sheets anciently: the fact that the geographically diverse Andamanese, Australian and New Guinean populations are all similarly related to this source suggests that the population is no longer extant, and the absence of long-range admixture linkage disequilibrium suggests that the population mixture did not occur in the last few thousand years.

As the authors note, this finding is consistent with ancient skeletal remains from the same region:

This discovery is striking in light of interpretations of the morphology of some early Native American skeletons, which some authors have suggested have affinities to Australasian groups. The largest number of skeletons that have been described as having this craniofacial morphology and that date to younger than ten thousand years have been found in Brazil6, the home of the Suruí, Karitiana and Xavante who in genetic data show the strongest affinity to Australasians.

How did this population reach the Amazonian basin? Perhaps the same way the Paleo-Amerindians did: across the Bering Strait and down through North America. If Negrito groups had reached south China and the Philippines, they could have continued up the East Asian shoreline and then down the west coast of North America. One problem with this model, raised by Greg Cochran and Steve Sailer, is that the "Australasian" admixture is absent from native North Americans. Keep in mind, however, that at least three waves of migration entered North America: the latest one corresponding to the Inuit-Aleut peoples, an earlier one corresponding to the Na-Dene peoples, and the earliest one corresponding to all other Amerindian groups. Only this earliest wave reached South America. There has consequently been much more population replacement among native North Americans than among native South Americans.

Population replacement is widely seen as something that has been done by European peoples (and, more recently, which is being done to them). In reality, the world was not a static place before Columbus. Human populations have been replacing each other for a very long time.

References

Cochran, G. (2018). Beringians, West Hunter, January 4

https://westhunt.wordpress.com/2018/01/04/beringians/

Dixon, R.B. (1923). The Racial History of Man, New York: Charles Scribner's Sons.

https://archive.org/stream/racialhistoryofm01dixo/racialhistoryofm01dixo_djvu.txt 

Frost, P. (2014). The Franz Boas you never knew, Evo and Proud, July 13 http://evoandproud.blogspot.ca/2014/07/the-franz-boas-you-never-knew.html 

Frost, P. (2015). More on the younger Franz Boas, Evo and Proud, April 18

http://evoandproud.blogspot.ca/2015/04/more-on-younger-franz-boas.html 

Rasmussen M, et al. (2011) An Aboriginal Australian genome reveals separate human dispersals into Asia, Science, 334(6052), 94-98.

http://europepmc.org/articles/pmc3991479

Reyes-Centeno, H., S. Ghirotto, F. Détroit, D. Grimaud-Hervé, G. Barbujani, and K. Harvati. (2014). Genomic and cranial phenotype data support multiple modern human dispersals from Africa and a southern route into Asia, PNAS, 111(20), 7248-7253.

https://s3.amazonaws.com/academia.edu.documents/40683950/Reyes-Centeno_et_al_2014.pdf?AWSAccessKeyId=AKIAIWOWYYGZ2Y53UL3A&Expires=1515619505&Signature=vu3uoN4c27lg0S3KhEsSWQw%2B4S4%3D&response-content-disposition=inline%3B%20filename%3DGenomic_and_cranial_phenotype_data_suppo.pdf 

Sailer, S. (2018). Were There People Already in the New World When the Indians Arrived? The Unz Review, January 6

http://www.unz.com/isteve/were-there-people-already-in-the-new-world-when-the-indians-arrived/

Skoglund, P., S. Mallick, M.C. Bortolini, N. Chennagiri, T. Hunemeier, M.L. Petzl-Erier, F.M. Salzano, N. Patterson, and D. Reich. (2015). Genetic evidence for two founding populations of the Americas, Nature, 525, 104-108

https://reich.hms.harvard.edu/sites/reich.hms.harvard.edu/files/inline-files/nature14895_Skoglund_2015.pdf

Stoneking, M. and F. Delfin (2010). The Human Genetic History of East Asia: Weaving a Complex Tapestry, Current Biology, 20(4), R188-R193 

http://www.sciencedirect.com/science/article/pii/S0960982209020673

Thangaraj, K., G. Chaubey, T. Kivisild, A.G. Reddy, V.K. Singh, et al. (2005). Reconstructing the origin of Andaman Islanders, Science, 308(5724), 996

https://www.researchgate.net/profile/Gyaneshwer_Chaubey/publication/7850233_Reconstructing_the_Origin_of_Andaman_Islanders/links/09e41508a88bf4dc2a000000.pdf

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

Trading in fair-skinned women. Did it happen elsewhere?

 

Austronesian woman (Roekiah Soeara, 1942, Indonesian actress - source). Austronesian and Papuan peoples intermixed in coastal Papua-New Guinea and on the islands to the east. This intermixture seems to have been mainly due to Austronesian women joining polygynous Papuan households. Did this happen through peaceful exchange (brides for land?) or through raiding and kidnapping? 

 

In all human populations, the sexes differ somewhat in skin color, women looking paler and men browner and ruddier. This sex difference is mirrored by a cross-cultural tendency to make lighter skin a female norm, which women often accentuate by various means (e.g., staying out of the sun, wearing sun-protective clothing, applying white facial powders or skin-bleaching preparations). Traditionally, this norm was said to be ‘white’ in Europe and East Asia, ‘golden’ in South-East Asia, and ‘red’ in sub-Saharan Africa (van den Berghe and Frost, 1986).

Why are women lighter-colored than men? Some ethologists have argued that light skin is one of several infant traits that the adult female body has adopted to calm aggressive impulses in men and induce caring behavior. This visual stimulus would thus influence male sexual response without being erogenous in and of itself. Whatever the ultimate cause, traditional social environments have tended to make women’s lighter skin a criterion of mate choice, often a leading one (Frost, 2011).

Evidently, skin color varies not only between men and women but also between different human populations. What happens when people become aware of the second kind of skin-color variation? Specifically, what happens to the feelings associated with the first kind? How are they transposed into this new social context?

One result may be a form of trade: women from lighter-skinned populations will become objects of commerce for sale to men in darker-skinned populations. This was the case between the 8th and 19th centuries, when women were exported from Europe to the Muslim world, i.e., Spain, North Africa, the Middle East, and South Asia (see previous post).

Has this kind of trade developed elsewhere? To be economically viable, it should meet certain conditions:

1. The two populations differ enough in skin color to make the trade worthwhile.

2. There is enough supply, i.e., the women are obtained for trade on a large enough scale through local wars or slave raiding.

3. There is enough demand, i.e., the male clients are polygynous enough and wealthy enough.

These conditions came together with the rise of the Muslim world to geopolitical dominance in the 8th century. Elsewhere, and at other times, the conditions were less optimal. People usually had little contact with other people whose skin color substantially differed from their own. In pre-Columbian America, for instance, it’s difficult to see how such trading could have developed, given the slight differences in skin color among different Amerindian groups.

Nonetheless, there are a few intriguing examples, albeit on a small scale:

Sub-Saharan Africa

Skin color does visibly differ among the various peoples of sub-Saharan Africa, to a greater degree in fact than what many non-Africans might think. These differences seem to interact with notions of sexual beauty, as Lugira (1970) writes about pre-colonial Uganda:

The Ganda concept of skin pigmentation considers light coloured complexions to be differing shades of white.  A dark brown skin colour is said to be — eruyeru, that is, somewhat white. A really brown‑reddish‑yellow person is said to be mweru = white, which in comparison would be considered to be blonde; and this in the Ganda aesthetic language is considered as red = myufu, the most perfect skin pigmentation.

As a result, the lighter skin of some groups could become a casus belli:

[…] The Nnyambo people were the handsome looking (brown‑red) inhabitants of the south of Buganda, in the Ziba countries and Kalagwe. The Nnyambo women were one of the reasons that induced Suna II to wage war with Kiziba after which he suffered from small pox and died (Lugira, 1970)

South-East Asia

An incipient trade of this sort existed in 19th- and 20th-century Thailand, where some Chinese merchants would offer their daughters to Thai rulers in exchange for protection and influence:

'Chinese of wealth', wrote the American missionary N. A. McDonald in 1884, 'often become favorites with the rulers and receive titles of nobility, and these noblemen in return present their daughters to Their Majesties.'

[…] William Skinner noted that Chinese women were 'prized for their light skin color'. Here, skin colour was valued as a form of feminine beauty and a sign of 'Chineseness'. (Jiemin, 2003)

This kind of exchange was consistent with indigenous Thai notions of female beauty, as shown by a recent study:

Young women in all four regions of Thailand considered ‘bright face skin’ and ‘white-pink (body) skin’ as the next most important physical appearance characteristics. Women in the North region were most concerned about having bright face skin, perhaps because they already tend to have lighter body skin which is viewed as desirable. Women in South region were most concerned with body skin color, which may be because they tend to have darker skin color. (Rongmuang et al., 2011)

Papua New Guinea / Melanesia

Finally, lighter-skinned women may have been objects of exchange in coastal Papua New Guinea and on the islands to the east (New Britain, New Ireland, the Solomons, Fiji). This area was a zone of intermixture between two streams of settlement: Papuans with dark brown if not black skin and Austronesians with light brown skin. Interestingly, this intermixture mainly took the form of Papuan men pairing with Austronesian women, as shown by comparison of paternally-transmitted Y chromosomes and maternally-transmitted mtDNA:

[…] This genetic admixture was most likely male biased involving mostly Austronesian women and, over time, mostly New Guinean men, resulting in a higher proportion of Melanesian than Asian Y-chromosome together with a higher proportion of Asian than Melanesian mtDNAs as observed in contemporary Polynesians (Mona et al. 2007; see also Kayser et al. 2006)

[…] mtDNA and NRY analyses indicate that this admixture was sex biased (Melton et al. 1995; Kayser et al. 2000; Su et al. 2000; Hurles et al. 2002): about 94% of Polynesian mtDNAs are of Asian ancestry, whereas about 66% of Polynesian Y chromosomes are of Near Oceania ancestry (Kayser et al. 2006). Although the mtDNA support for this sex-biased admixture hypothesis has recently been questioned (Soares et al. 2011), genome-wide SNP data do indicate significantly more Asian versus New Guinea ancestry for the X chromosome of Polynesians than for the autosomes (Wollstein et al. 2010), in agreement with the sex-biased admixture scenario. In addition, Papuan-speaking groups in New Guinea show higher frequencies of Asian mtDNA haplogroups than of Asian NRY haplogroups (Kayser, Choi, et al. 2008).

[…] Overall, the mtDNA haplogroups in the Solomons are predominantly of Asian [i.e., Austronesian] origin, whereas the NRY haplogroups are predominantly of NO [Near Oceania, i.e., Papuan] origin. (Delfin et al, 2012)

Since Papuans are much more polygynous than Austronesians, and in the past more patrilocal, this intermixture was probably due to Austronesian women traveling over some distance and joining polygynous Papuan households.¹ How and why is anyone’s guess. Peaceful exchange? “Give us some of your land and we’ll give you some of our women?” Or was it raiding and kidnapping?

In either case, the two groups were probably keenly aware that one of them was lighter-skinned and the other darker-skinned. Even today, after millennia of intermixture, color consciousness remains strong in this contact zone, as noted by a study of the Eastern Solomons:

The Lau were conscious of skin color; some parents, particularly mothers, tried to dissuade their sons from marrying much better-educated girls from the Western Solomons because of their dark skins. Although color consciousness is decreasing, until quite recently clans and persons of higher status have been generally lighter, and marriages have been preferentially within clan or class status levels. (Baldwin and Damon, 1973)

According to an origin myth from New Britain, these differences in skin color arose through the marriage choices of two brothers:

To-Kabinana said to To-Karvuvu, “Do you get two light-coloured coco-nuts. One of them you must hide, then bring the other to me.” To-Karvuvu, however, did not obey, but got one light and one dark nut, and having hidden the latter, he brought the light-coloured one to his brother, who tied it to the stern of his canoe, and seating himself in the bow, paddled out to sea. He paid no attention to the noise that the nut made as it struck against the sides of his canoe nor did he look around. Soon the coco-nut turned into a handsome woman, who sat on the stern of the canoe and steered, while To-Kabinana paddled. When he came back to land, his brother was enamoured of the woman and wished to take her as his wife, but To-Kabinana refused his request and said that they would now make another woman. Accordingly, To-Karvuvu brought the other coco-nut, but when his brother saw that it was dark-coloured, he upbraided To-Karvuvu and said: “You are indeed a stupid fellow. You have brought misery upon our mortal race.  From now on, we shall be divided into two classes, into you and us.” Then they tied the coco-nut to the stern of the canoe, and paddling away as before, the nut turned into a black-skinned woman; but when they had returned to shore, To-Kabinana said: “Alas, you have only ruined our mortal race.  If all of us were only light of skin, we should not die.  Now, however, this dark-skinned woman will produce one group, and the light-skinned woman another, and the light-skinned men shall marry the dark-skinned women, and the dark-skinned men shall marry the light-skinned women.” And so, To-Kabinana divided mankind into two classes. (Gray, 1916, p. 108)

Conclusion

Light-skinned European women became objects of commerce because of an unusual set of circumstances, essentially the relative dominance of the Muslim world and, correspondingly, the relative weakness of the European world.

Circumstances may come and go, but basic notions of human beauty change less quickly. In the near future, a similar situation may develop in response to the impoverishment of common people in Europe and North America and the growing affluence of elites in the Third World, particularly in resource-rich countries.

Note

1. The literature also puts forward the reverse scenario as a possible explanation, i.e., Papuan men marrying into Austronesian communities. In this second scenario, Papuan men would have had to renounce not only patrilocality but also polygyny and low paternal investment. This is a more radical behavioral change than the one associated with Austronesian women marrying into Papuan communities. Elsewhere in the world, we have two other examples of a high-polygyny population coming into contact with a low-polygyny one: Bantu and Khoisans in southern Africa and Bantu and Pygmies in central Africa. In both cases, intermixture has almost wholly involved women moving from the low-polygyny population to the high-polygyny one. There has been little if any movement of men in the other direction.

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The Spanish online journal La Tercera Cultura has recently translated and published one of my posts: “Cómo se llegó a pacificar Europa.”

 

References

Baldwin, J.C. and A. Damon. (1973). Some genetic traits in Solomon Island populations, American Journal of Physical Anthropology, 39, 195-201.

Delfin, D., S. Myles, Y. Choi, D. Hughes, R. Illek, M. van Oven, B. Pakendorf, M. Kayser, and M. Stoneking. (2012). Bridging Near and Remote Oceania: mtDNA and NRY Variation in the Solomon Islands, Molecular Biology and Evolution, 29(2), 545–564.

http://mbe.oxfordjournals.org/content/29/2/545.short

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. (2010). Femmes claires, hommes foncés. Les racines oubliées du colorisme, Quebec City : Presses Universitaires de Laval.

Gray, L.H. (1916). The Mythology of All Races, Vol. 9 Oceanic, Boston: Marshall Jones.

Jiemin, B. (2003). The Gendered Biopolitics of Marriage and Immigration: A Study of Pre-1949 Chinese Immigrants in Thailand, Journal of Southeast Asian Studies, 34(1), 127-151.

http://www.jstor.org/discover/10.2307/20072478?uid=3737720&uid=2&uid=4&sid=21102467085371

Kayser M, S. Brauer, R. Cordaux R, et al. (2006). Melanesian and Asian origins of Polynesians: mtDNA and Y chromosome gradients across the Pacific, Molecular Biology and Evolution, 23, 2234-2244.

http://mbe.oxfordjournals.org/content/23/11/2234.abstract

Lugira, A.M. (1970). Ganda Art, Kampala: Osasa pub.

Mona, S., M. Tommaseo-Ponzetta, S. Brauer, H. Sudoyo, S. Marzuki, and M. Kayser. (2007). Patterns of Y-Chromosome Diversity Intersect with the Trans-New Guinea Hypothesis, Molecular Biology and Evolution, 24 (11), 2546-2555.

http://mbe.oxfordjournals.org/content/24/11/2546.short

Rongmuang, D., B.J. McElmurry, L.L. McCreary, C.G. Park, A. Miller, and C. Corte. (2011). Regional Differences in Physical Appearance Identity among Young Adult Women in Thailand, Western Journal of Nursing Research, 33(1), 106-120.

http://dspace.lib.uic.edu/handle/10027/8345

Van den Berghe, P. L. and 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.

Ich bin Mittel-Ostländer?

Spread of farming in Europe. Der Spiegel

New research has revealed that agriculture came to Europe amid a wave of immigration from the Middle East during the Neolithic period. The newcomers won out over the locals because of their sophisticated culture, mastery of agriculture -- and their miracle food, milk.
(Schulz 2010)

This recent Der Spiegel article has stirred up comment in the blogosphere (Hawks 2010, Khan 2010, Sailer 2010). It argues that Europeans do not descend from the reindeer hunters who once roamed the continent during the last ice age. Nor do they descend from the more recent hunter-fisher-gatherers of the Mesolithic. All of those people went extinct. They were replaced by the real ancestors of present-day Europeans—farmers who began to spread out of the Middle East only 9,000 years ago and who reached northern Europe two millennia later—almost at the dawn of history!

If you have any doubts, this finding is based on “a barrage of articles in professional journals like Nature and BMC Evolutionary Biology, [whose authors] have turned many of the prevailing views upside down over the course of the last three years.”

There is nothing wrong with the above journal articles. A lot is wrong, however, with the Der Spiegel article. It neatly confuses two separate findings, only one of which supports the ‘population replacement’ hypothesis.

1. Origins of the European allele for adult digestion of lactose

Unlike most humans, Europeans can digest milk sugar (lactose) as adults. This is made possible by an allele that allows adults to produce an enzyme, lactase, that breaks down milk sugar. So where did this allele come from? Did it originate in Europe or in some place outside Europe?

According to Der Spiegel:

But where did the first milk drinker live? Which early man was the first to feast on cow's milk without suffering the consequences?

In a bid to solve the mystery, molecular biologists have sawed into and analyzed countless Neolithic bones. The breakthrough came last year, when scientists discovered that the first milk drinkers lived in the territory of present-day Austria,
Hungary and Slovakia.

The reader is left with the impression that the new allele had been brought to Europe from the Middle East. That impression is false. In fact, the above molecular biologists found no trace of this allele in DNA retrieved from the earliest European farmers. It apparently arose later as a mutation and then spread among Europeans through natural selection.

[…] the absence of the 13.910*T allele in our Neolithic samples indicates that the early farmers in Europe were not yet adapted to the consumption of unprocessed milk. Dairying is unlikely to have spread uniformly over Europe, and the use of milk in the Early Neolithic may have been rare. Although our data are consistent with strong selection for LP [lactose persistence] beginning with the introduction of cattle to Europe ≈8800 B.P., it is unlikely that fresh milk consumption was widespread in Europe before frequencies of the 13.910*T allele had risen appreciably during the millennia after the onset of farming.
(Burger et al. 2007)

Consequently, this area of research argues against the Der Spiegel article. Europeans did change genetically, but the change occurred through natural selection, not through population replacement (1).

2. Genetic divide between late hunter-fisher-gatherers and early farmers

Researchers have also retrieved mitochondrial DNA from Europe’s late hunter-fisher-gatherers and early farmers. Comparison shows a sharp genetic divide between the two groups. In particular, the first group had high incidences of haplogroup U—a genetic lineage that was rare among early farmers and still is among present-day Europeans.

The past year, however, has brought evidence of genetic continuity. After studying 92 Danish human remains that range in time from the Mesolithic to the Middle Ages, Melchior et al. (2010) found that high incidences of haplogroup U persisted among the earliest farmers and declined only in later groups.

Thus, the sharp genetic divide was not between late hunter-fisher-gatherers and early farmers. It seems to have been between the earliest farmers and groups that had been farming for at least a millennium or so. Once again, the evidence points to natural selection, and not to population replacement.

But isn’t mtDNA unresponsive to natural selection? That’s what I and others used to think. There is growing evidence, however, that some mtDNA loci can change in response to natural selection. In particular, some haplogroups seem to reflect a tradeoff between thermogenesis and ATP synthesis (Balloux et al 2009). If true, the decline of U-type haplogroups among early farmers may reflect the differences in physical activity (leading to overheating or underheating) that exist between hunting/fishing/gathering and farming.

Conclusion

The jury is still out. The evidence, however, seems to be tilting toward natural selection and away from population replacement as the best way to explain these genetic changes among ancestral Europeans. In short, the Der Spiegel article is bad science.

And bad journalism.

Note

1. Towards the end, the Der Spiegel article seems to acknowledge that the allele for adult digestion of lactose must have arisen after farming had spread to Europe:

Some [farmers] had genetic mutations that enabled them to drink milk without getting sick. They were the true progenitors of the movement.

As a result of "accelerated evolution," says Burger, lactose tolerance was selected for on a large scale within the population in the space of about 100 generations. Europe became the land of the eternal infant as people began drinking milk their whole lives
(Schulz 2010)

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.
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2817182/?tool=pmcentrez

Burger, J., M. Kirchner, B. Bramanti, W. Haak, and M.G. Thomas. (2007). Absence of the lactase-persistence-associated allele in early Neolithic Europeans, Proceedings of the National Academy of Science, 104(10), 3736-3741.
http://www.pnas.org/content/104/10/3736.full

Hawks, J. (2010). Neolithic milk fog, John Hawks weblog, October 17.
http://johnhawks.net/weblog/topics/demography/neolithic/spiegel-volkerwanderung-2010.html

Khan, R. (2010). Völkerwanderung back with a vengeance, Discover, October 17.
http://blogs.discovermagazine.com/gnxp/2010/10/volkerwanderung-back-with-a-vengeance/
Melchior, L., N. Lynnerup, H.R. Siegismund, T. Kivisild, J. Dissing. (2010). Genetic diversity among ancient Nordic populations, PLoS ONE, 5(7), e11898.
doi:10.1371/journal.pone.0011898

Sailer, S. (2010). Are Europeans all Middle Easterners? October 17.
http://isteve.blogspot.com/2010/10/are-europeans-all-middle-easterners.html

Schulz, M. (2010). How Middle Eastern Milk Drinkers Conquered Europe, Spiegel Online International, October 15.
http://www.spiegel.de/international/zeitgeist/0,1518,723310,00.html