Rapid onset of Aurignacian in Southwest France

Rapid onset of Aurignacian in Southwest France

Journal of Archaeological Science doi:10.1016/j.jas.2011.09.019

A Radiocarbon chronology for the complete Middle to Upper Palaeolithic transitional sequence of Les Cottés (France)

Sahra Talamo et al.

The Middle to Upper Palaeolithic transition is the key period for our understanding of Neanderthal and modern human interactions in Europe. The site of Les Cottés in south-west France is one of the rare sites with a complete and well defined sequence covering this transition period. We undertook an extensive radiocarbon dating program on mammal bone which allows us to propose a chronological framework of five distinct phases dating from the Mousterian to the Early Aurignacian at this site. We found that the Mousterian and Châtelperronian industries are separated from the overlying Protoaurignacian by a gap of approximately 1000 calendar years. Based on a comparison with Upper Paleolithic sites in Europe we see an overlap in the ages of Châtelperronian industries and Aurignacian lithic assemblages, which are usually associated with Anatomical Modern Humans, which is consistent with an acculturation at distance model for these late Neanderthals. The Proto and Early Aurignacian appear contemporaneous indicating that this transition was rapid in this region. Anatomically Modern Humans are present at the site of Les Cottés at least at 39,500 cal BP roughly coincident with the onset of the cold phase Heinrich 4.

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mtDNA and ethnic differentiation in East Africa

mtDNA and ethnic differentiation in East Africa

From the paper:

The pattern observed in East Africa (with the exception of the Khoisan-related Hadza and Sandawe populations), which combines a high level of within-population diversity with strong genetic structure among populations, suggests the occurrence of periodical episodes of admixture in these populations, separated by periods of isolation and genetic drift. Indeed, the observation of high levels of diversity within populations could be due to long-term large effective population sizes maintained in East Africa. In this case, however, little genetic structure between populations should be expected, since there would be little opportunity for genetic drift to act. Alternatively, gene flow can produce high within population diversity, and in the present case, it could also account for the extensive sharing of haplotypes and haplogroups observed between the Nyangatom and the Daasanach, as well as with other populations.

This seems like a very clever observation: substantial gene flow and a large effective population size would be inconsistent with population structure, as the different populations would be homogenized and drift would not be able to differentiate them. Long-term lack of gene flow, on the other hand, would not explain the sharing of haplotypes between populations, as each population would develop its own distinctive genetic signatures over time. Thus, the simplest explanation for the observed pattern is that gene flow has indeed occurred (accounting for the sharing of haplotypes), but that it was not continuous (accounting for the fact that populations are, after all, substantially differentiated).

From the paper:

The intermediate linkage disequilibrium (LD) found in East Africa (Tishkoff et al., 1996) in contrast with Europe (high LD) and Sub-Saharan Africa (low LD, Tishkoff & Kidd, 2004; Conrad et al., 2006), could be due to such admixture events, more frequently occurring in this region compared to other Sub-Saharan populations. Substantial levels of gene flow among Nilo-Saharan, Afro-Asiatic and Niger-Congo populations from Tanzania have already been inferred by Tishkoff et al. (2007a) and our results suggest that these gene flows could have occurred in a larger region extending up to Southern Ethiopia.

Indeed, in the absence of recent admixture, the East African populations would exhibit similar levels of LD with Sub-Saharan Africans., or even lower, as the indigenous East Africans are arguably older than those of the interior of the continent. The fact that they exhibit higher LD (intermediate between Europe and Sub-Saharan Africa) can be explained by admixture, i.e., the fact that they have inherited long stretches of DNA from the parental populations in each admixture event, and that time since that event has not been sufficiently long to cause the decay of these chunks into smaller pieces.

And, from the conclusions of the paper:

The high diversity in East Africa was interpreted as a sign of an ancient origin. However, our results might indicate that this high diversity could also come from a particular history of recent migrations and admixture promoted by the pastoralist societies that dominate in the region.

Note, that an East African origin of mankind is still the best hypothesis on palaeoanthropological and simply geographical grounds. However, the high genetic diversity found in East Africa does not necessarily reflect the antiquity of that population, but rather its history of repeated admixture by peoples of different origins.

There are two alternative hypotheses for why East Africans accumulated so much genetic diversity:

1. They are the oldest population, and have been accumulating genetic diversity for the longest period of time
2. They are substantially admixed with very divergent components (e.g., Semites, Nilo-Saharans, Cushitic speakers, and so on)

A not-so-bad example would be to compare them with other known population sources in the world, e.g., Anatolia, from where multiple waves of humans entered Europe in Paleolithic and Neolithic times. Many would agree that such movements took place, but it would be incorrect to see the population of Anatolia as a little-altered descendant of its earliest inhabitants, as the current genetic diversity observed there is -at least in part- the result of the settlement of the region by peoples from the Balkans, Central Asia, Levant, and even Western Europe.

Ann Hum Genet. 2009 Aug 25. [Epub ahead of print]

Genetic Evidence for Complexity in Ethnic Differentiation and History in East Africa.

Poloni ES, Naciri Y, Bucho R, Niba R, Kervaire B, Excoffier L, Langaney A, Sanchez-Mazas A.

Summary

The Afro-Asiatic and Nilo-Saharan language families come into contact in Western Ethiopia. Ethnic diversity is particularly high in the South, where the Nilo-Saharan Nyangatom and the Afro-Asiatic Daasanach dwell. Despite their linguistic differentiation, both populations rely on a similar agripastoralist mode of subsistence. Analysis of mitochondrial DNA extracted from Nyangatom and Daasanach archival sera revealed high levels of diversity, with most sequences belonging to the L haplogroups, the basal branches of the mitochondrial phylogeny. However, in sharp contrast with other Ethiopian populations, only 5% of the Nyangatom and Daasanach sequences belong to haplogroups M and N. The Nyangatom and Daasanach were found to be significantly differentiated, while each of them displays close affinities with some Tanzanian populations. The strong genetic structure found over East Africa was neither associated with geography nor with language, a result confirmed by the analysis of 6711 HVS-I sequences of 136 populations mainly from Africa. Processes of migration, language shift and group absorption are documented by linguists and ethnographers for the Nyangatom and Daasanach, thus pointing to the probably transient and plastic nature of these ethnic groups. These processes, associated with periods of isolation, could explain the high diversity and strong genetic structure found in East Africa.

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A different look at the Olympic Medal Count

A different look at the Olympic Medal Count

The Athens Olympics are now over and Greece won 16 medals. The best-performing nations, according to the official medal count are the United States, China, Russia, Australia and Japan. A different look at the medal count of the Olympics comes from the Australian Bureau of Statistics which has compiled a world ranking based on population per gold medal. The Bahamas, Norway, Australia, Hungary and Cuba lead this ranking, with Greece placing 8th. At the bottom of the table, Syria, Mexico, Colombia, Nigeria and India.

Dutch Hair Color Preferences

Dutch Hair Color Preferences

Gentlemen prefer blondes, women go for black

5 August 2004

AMSTERDAM — Dutch men prefer blondes and over half of Dutch women want to be blond or blonder than their present shade, particularly in the summer, according to research published Thursday.

The study carried out by research bureau Blauw Research for shampoo manufacturer Andrelon also found that women find men with dark hair more attractive.

Some 71 percent of the 535 people, aged 18 to 55, polled said they were satisfied or very satisfied with their own hair colour. Men were more satisfied with their hair colour than women.

Two out of five women were natural blondes and a slightly higher number were brunettes. The same applies to the men, though more men than women were black haired. Red hair was the rarest colour, Novum Nieuws reported.

Several women polled no longer to know what their original hair colour was.

About half of the women said they coloured their hair regularly, with 35 percent admitting to using dye. Half of the women polled have used highlights to make their hair appear blonder.

Some 10 percent put their faith in nature, relying on the sun to make their hair blonder.

The survey found that men — more so than women — believe blond hair makes a person look younger.

Women, on the other hand, were more in favour of men with dark hair, with just 17 percent of females questioned saying blond men were very attractive.

[Copyright Expatica News 2004]

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EURO-DNA test

EURO-DNA test

AncestryByDNA has released a EURO-DNA test which reports percentages of "Northern European," "Southeastern European," "Middle-Eastern," and "South Asian" admixture based on a 320 ancestry-informative markers (AIMs).

The ad-hoc choice of the four ancestral groups and the rather confusing commentary and/or anomalous results (Iberians on average ~16% "South Asian"?) may discourage many from taking the test, especially at a price tag of $399. Still, EURO-DNA is a step towards personalized genetic archaeology, even though the theoretical assumptions and methodology leave much to be desired at this stage.

Update:

If you start with the a priori breakdown into 4 groups, then each individual will have 4 numbers that add up to 100%. One could just as easily have used a "Southwestern European", "Northeastern European", "Middle Eastern" and "South Asian" breakdown, and again each individual would have 4 numbers adding up to 100%.

The trick is to start with a collection of individuals, remove identifying tags and cluster them, thus identifying the real genetic components in the population, if any such components can be detected. This was the procedure followed by Rosenberg et al. [1]. In that analysis, wholly different clusterings emerged, with e.g., the specificity of Iberian Basques, who were allocated their own cluster, was discovered.



By contrast, an Iberian Basque taking the EURO-DNA test would perhaps get a score high in NOR/MED which however obfuscates the real genetic structure of the Basque population which is highly specific, as the Basques are an ancient ethnolinguistic isolate of the Iberian peninsula rather than the product of "admixture".

AncestryByDNA must show why its chosen four-group breakdown is used in lieu of other potential choices.

[1] Rosenberg et al (2002)

Update #2: Check out the comments for some additional information by Dr. Tony Frudakis of DNAPrint who is involved in the creation of EURO-DNA 1.0 and the AncestryByDNA tests.

The German Hyperbrachycephals

The German Hyperbrachycephals

According to the Nordicist school, European achievement is primarily due to the tall, blond, dolichocephalic race. The only problem with this theory, which achieved such popularity in the 19th and early 20th centuries, is that when the skulls of prominent Europeans and Germans were measured there was no evidence of an overrepresentation of dolichocephals among them: indeed, most of them were brachycephalic, many of them tending to the extreme hyperbrachycephalic form, as the following passage illustrates.

Friedrich Hertz, Rasse und Kultur: eine kritische Untersuchung der Rassentheorien, 3. ed., Alfred Kröner, Leipzig, 1925, p.163

Sehen aber die Genies wirklich in der Regel so aus [DP: Germanisch Typus]? Genaue Feststellungen liegen leider nur selten vor. Immerhin können wir sagen, dass die Genies sehr häufig - vielleicht selbst in der Mehrzahl der Fälle - diesen Anforderungen nicht entsprechen. Vor allem ihr Schädel nähert sich meist ganz bedenklich der "Kreislinie tierischen Wohlbehagens", wie Chamberlain so schön sagt. Bismarck, Luther, Laplace, Napoleon, Pascal, Raphael, Beethoven, Haydn, Schubert sind einige Beispiele von Rundköpfen, ja, es scheint gerade die extreme Form der Rundköpfigkeit, die Hyperbrachycephalität, die man mit dem Index 85 beginnen lasst, unter ihnen sehr häufig zu sein). Schillers Schadel mit seinem Index von 84 steht knapp an inhrer Grenze, Kant mit seiner Indexnummer von 88.5 war ein ganz ausgesprochener Hyperbrachycephale. Hamerling hatte den Index 85.3, Schopenhauer den von 86, Leibniz gar einen von 90.3.

UPDATE (2 March 2008)

Franz Weidenreich, "The Brachycephalization of Recent Mankind", Southwestern Journal of Anthropology, Vol. 1, No. 1. (Spring, 1945), p. 9.

One can imagine the shock an intelligent German reader suffered when he remembered that many of the great German heroes from Bismarck down to Hindenburg and Hitler were brachycephalics and even hyperbrachycephalics, and that the three greatest philosophers Germany has produced-Leibniz, Kant, and Schopenhauer-had round heads in the most extreme form (Fig. 2, No. 4, Leibniz, skull index 90.3[!]; NO. 5, Kant, skull index 88.5; No. 6, Schopenhauer, head index 90.0 [!).

Higher female effective population size in recent human evolution

Higher female effective population size in recent human evolution

The common maternal ancestor of all living humans appears to be much older than the common paternal ancestor of all living men. It has been suggested that selection on the Y-chromosome is responsible for this discrepancy, that is, that a recent male line has wiped out older lines because of some unspecified advantage. This new study indicates that this is not the case, and rather that the female effective population size was higher than the male one, which is likely due to the practice of successful males to have many children with different wives (polygyny).

Mol Biol Evol. 2004 Aug 18 [Epub ahead of print]

Genetic Evidence for Unequal Effective Population Sizes of Human Females and Males.

Wilder JA et al.

The time to the most recent common ancestor (TMRCA) of the human mitochondria (mtDNA) is estimated to be older than that of the non-recombining portion of the Y chromosome (NRY). Surveys of variation in globally distributed humans typically result in mtDNA TMRCA values just under 200 thousand years (kya) while those for the NRY range between 46 and 110 kya. A favored hypothesis for this finding is that natural selection has acted on the NRY leading to a recent selective sweep. An alternate hypothesis is that sexbiased demographic processes are responsible. Here we re-examine the disparity between NRY and mtDNA TMRCAs using data collected from individual human populations--a sampling strategy that minimizes the confounding influence of population subdivision in global datasets. We survey variation at 782 bp of the mitochondrial cytochrome c oxidase subunit 3 gene as well as at 26.5 kb of non-coding DNA from the NRY in a sample of 25 Khoisan, 24 Mongolians, and 24 Papua New Guineans. Data from both loci in all populations are best described by a model of constant population size, with the exception of Mongolian mtDNA which appears to be experiencing rapid population growth. Taking these demographic models into account, we estimate the TMRCAs for each locus in each population. A pattern that is remarkably consistent across all three populations is an approximately two-fold deeper coalescence for mtDNA than for the NRY. The oldest TMRCAs are observed for the Khoisan (73.6 kya for the NRY and 176.5 kya for mtDNA) while those in the non-African populations are consistently lower (averaging 47.7 kya for the NRY and 92.8 kya for mtDNA). Our data do not suggest that differential natural selection is the cause of this difference in TMRCAs. Rather, these results are most consistent with a higher female effective population size.
Link (pdf)