subota, 18. kolovoza 2012.

Stone Age skull-smashers spark a cultural mystery


AN UNUSUAL cluster of Stone Age skulls with smashed-in faces has been found carefully separated from the rest of their skeletons. They appear to have been dug up several years after being buried with their bodies, separated, then reburied.
Collections of detached skulls have been dug up at many Stone Age sites in Europe and the Near East - but the face-smashing is a new twist that adds further mystery to how these societies related to their dead.
Juan José Ibañez at the Spanish National Research Council in Barcelonasays the find may suggest that Stone Age cultures believed dead young men were a threat to the world of the living.
No one knows why Neolithic societies buried clusters of skulls - often near or underneath settlements. Some think it was a sign of ancestral veneration. "When people started living together [during the Neolithic period], they needed a social cement," says Ibañez. Venerating ancestors might have been a way of doing this. But the violence demonstrated towards the skulls in the latest cluster suggests a different story.
The 10,000-year-old skulls were found in Syria. Like those found in other caches, they have been cleanly separated from their spines, suggesting they were collected from dead bodies that had already begun to decompose. Patterns on the bone indicate that some had been decomposing for longer than others, making it likely that they were all gathered together for a specific purpose.
Most of the skulls belonged to adult males between 18 and 30 years old. One - belonging to a child - was left intact; one was smashed to pieces; the remaining nine lacked facial bones. "There was a pattern," says Ibañez. "The top of the skull and the jaw were there, but they were missing all of the bones in between." His team believes the facial bones were smashed out with a stone and brute force. "There were no traces of cutting," he says (American Journal of Physical AnthropologyDOI: 10.1002/ajpa.22111).
Ibañez reckons Stone Age people believed they would receive some benefit - perhaps the strength of the young men the skulls once belonged to - by burying them near or beneath their settlements. Why the faces were smashed in invites speculation.
It may have been an act of spite or revenge, says Ibañez. Or the skulls may have been brought together to create a "community of the dead", perhaps in order to spiritually interact with the living.
"The post-mortem violence suggests young men were seen as carrying a particular threat," says Stuart Campbell at the University of Manchester, UK. Destroying their facial structures may have been a way of destroying the individuals' identities, he says.
Liv Nilsson Stutz at Emory University in Atlanta, Georgia, says the act could have helped deal with grief. "Taking away facial identity could be a way of separating the dead from the living," she says.

The genetic history of Europeans (Pinhasi et al. 2012)



This is a nice paper with extensive references on the topic of European origins. Two of its co-authors, Joachim Burger, and Ron Pinhasi are leading a couple of exciting new ancient DNA projects that will probably flood us with interesting new data in the years to come.

From the paper:
Human evolutionary history includes all the complex demographic, natural selection, and stochastic processes that have shaped our species. Despite the limitations of genetic and archaeological data to inform on all the details of human evolution, they constitute an irreplaceable source of information to appraise the key episodes that are likely to have had major impacts on patterns of genetic, morphological, and cultural variation. When considering AMH in Europe, three such critical periods are apparent: (i) the expansion of AMH out of Africa and their colonization of Europe approximately 45 000 years ago (45 ka), (ii) the last glacial maximum (LGM) and the formation of uninhabitable areas in Europe between 27 and 16 ka, and (iii) the arrival of Neolithic culture in southeast Europe and its spread throughout the rest of the continent between 9 and 5 ka. Here we review genetic evidence describing these major demographic episodes in the context of archaeological and chronological data. 
I have postulated that there was at least one important post-5ka event affecting Europe. But, in order to understand how events played out before 5ka and the present, we must first understand the background of what was taking place in Europe before 5ka.

On the earliest settlement of Europe:
Until recently, the earliest date for the first appearance of AMH in Europe had been set to around 42 to 43 ka solely based on their proposed association with Aurignacian artifacts (Table 1) [5,6]. New direct radiocarbon dates of fossils support this view and indicate that AMH appeared in Europe by 44.2– 41.5 calibrated (cal.) ka BP at Kent’s Cavern in southern England [6] and by 45–43 cal. ka BP in Grotta del Cavallo, Italy [7], whereas Neanderthals did not survive in most of Europe and the Caucasus after 39 cal. ka BP [8,9].
These dates are so close to the MP/UP transition in the Levant (49-46 cal ky BP), with the Aurignacian appearing shortly thereafter in both Central Europe and Italy. It would appear that modern humans swiftly colonized Europe after they made the crucial UP leap. Of course, in my opinion, this population was ultimately descended from inhabitants of Arabia, escaping post-70ka climatic deterioration and pre-100ka with the archaeologically attestedNubian Complex. But, in any case, it is probably the last crucial step, when humans went into warp drive post-50ka that led to the first modern human colonization of Europe and ultimately the extinction (or absorption?) of the Neandertals.

But, the early colonizers were in for a rough patch of climate that last for several millennia, making whole parts of Europe uninhabitable, and allowing few ones to survive in the south of the continent:
After the disappearance of the Neanderthals and particularly during the LGM, the northern parts of Europe were covered by ice sheets, leaving humans to survive in poorly resourced environments [10,11]. Parts of northern Europe were either completely abandoned [12] or sparsely populated [13]. The archaeological record of this period catalogs a complex series of interrelated material cultures that vary in their geographic ranges and temporal durations (Table 1). Spatial patterns of material culture change have been interpreted as indicating colonization of regions up to 52 degrees N latitude during the Gravettian, followed by partial or complete retreat of most northern populations by 24 ka, and recolonization of these regions by 20–16 ka, with some continuity of occupation in more southern latitudes [14]. However, the extent to which material cultures correspond to distinct human populations, and to which their distribu- tion changes through time correspond to demographic pro- cesses, remains unclear. 
The following table presents a very useful summary of archaeological developments in west Eurasia:

So far, we have substantial autosomal data of modern humans only from the Mesolithic onwards (Iberia), but also mtDNA from much older specimens of the Gravettian in Italy and Russia.

Apparently, other people are looking to extract ancient genomic DNA from older remains as well:
A group led by evolutionary geneticist Johannes Krause of the University of Tubingen, Germany, is trying to remove and reassemble nuclear DNA from the bones of roughly 20,000-year-old people in Europe. If successful, that effort will provide the first look at whether Stone Age humans carried more Neandertal genes than people today do. “It’s a completely open question whether more interbreeding occurred in the past than what we’ve found so far,” Krause says.
But, let's see where things stand now.

Ancient mtDNA sequences recovered from three Upper Paleolithic and 14 Mesolithic and Neolithic hunter-gatherers all belong to the mtDNA haplogroup U [48], currently found at frequencies between 1 and 7% in most modern European populations, but at up to 20% in Baltic populations and around 40% in Saami. Interestingly, almost all pre-Neolithic hunter-gatherers from Central and Northeastern Europe sequenced to date, and the majority of European post-Neolithic hunter-gatherers, carry U-type mtDNA [48,49] (Figure 1a,c). There are three exceptions: two Italian individuals with N* and pre-HV types [50], and one from Sweden [46]; the latter dating to the late Neolithic and possibly being the result of an admix- ture event with incoming farmers. In all other hunter- gatherer samples, the now common mtDNA lineages H, T, K, and J are absent, suggesting that these mtDNA lineages were introduced during the Neolithic period. 

The mtDNA evidence is indeed the strongest argument for large-scale population replacement during the Neolithic, a scenario which has found support by the sequencing of Neolithic hunter-gatherers from Gotland Sweden and Mesolithic ones from Iberia.

The authors note that while early farming groups largely lacked mtDNA haplogroup U, the later ones possessed it to some extent:

Maps showing Europe in times slices and depicting the locations from which ancient mitochondrial DNA (mtDNA) sequences were retrieved. Squares represent hunter-gatherer individuals and circles represent farming individuals. Lineages belonging to the U-clade are shown in red. Other lineages are shown in yellow. (a) Paleolithic and Mesolithic hunter-gatherers 13 500–8300 BP (plotted on a map ofEurope during the last glacial maximum ca 22 000 BP).All Pleistocene hunter-gatherers analyzed to date carry mitochondrial lineages that belong to one of the U-clades: U2, U4, or U5. (b) Early farmers 7600–6500 BP. The map illustrates the approximate arrival times and duration of the earliest Neolithic cultures (in years BP). Very few of the early farmers belong to one of the U-clade mtDNA haplotypes, indicating discontinuity between Paleolithic/Mesolithic hunter-gatherers and early farmers [48,64]. (c) Later hunter-gatherers 6500–4500 BP. Whereas early hunter-gatherers carry exclusively mitochondrial U-lineages,later hunter-gatherers show additional lineages that are also present in early farming groups(b), pointing to a possible admixture between the groups or a change in lifestyle of former farmers back to hunting-gathering in Northern Europe. (d) Later farmers 6500–4500 BP. Compared to the period of the first appearance of farmers, late farmers have a significantly higher frequency of U-lineages. This can be explained by increasing rates of admixture between farmer and hunter gatherer groups during this period and by the adoption of a farming lifestyle by hunter-gatherers. The maps are adapted from [69] and show datapoints from [46,48,51, 54–56,61,62,64,70,71]. Abbreviation: BP, before present. 

And, of course, we have the ubiquitous Y-haplogroup G2a as the lineage par excellence of the first European farmers:

In contrast to mtDNA, ancient Y-chromosome data has until recently been less informative, but a single Y-chro-mosome haplotype (G2a) in 20 of 22 male individuals from the Late Neolithic cave site at Treilles [62] led to the hypothesis that a small male founding population arrived in Southern France, probably by a maritime route from the eastern Mediterranean, in the early Neolithic. The same haplotype was also found in five of six individuals from the Avellaner Cave [61] and in one out of three Central Euro-pean LBK individuals [63]. If authentic, the presence of the Y-chromosome haplogroup G2a in 26 of 31 Neolithic individuals from Germany, France, and Spain is both surprising and intriguing, but this requires further examination. 
The only high coverage genome sequence of a prehistoric European individual is that of the Tyrolean Iceman, Oetzi, a 5300 year-old individual from South Tyrol, which was recently reported at 7-fold coverage [45]. Comparison with 1300 contemporary Europeans indicated closest genetic affinities with southern Europeans, particularly inhabi-tants of the Tyrrhenian Islands. Intriguingly, this is also the region where the Y-chromosome haplotype of the Ice-man is found at highest frequency, and this haplotype belongs to the same G2a haplogroup described above.
And of course:
Future research should also reveal the effects of post-Neolithic demographic processes, including migration events, which preliminary data suggest had a major impact upon the distribution of genetic variation. These include events associated with Bronze Age civilizations, Iron Age cultures, and later migrations, including those triggered by the rise and fall of Empires.
The recovery of the European past has only just begun.


Trends in Genetics doi:10.1016/j.tig.2012.06.006

The genetic history of Europeans 

Ron Pinhasi, Mark G. Thomas, Michael Hofreiter, Mathias Currat, Joachim Burger

The evolutionary history of modern humans is characterized by numerous migrations driven by environmental change, population pressures, and cultural innovations. In Europe, the events most widely considered to have had a major impact on patterns of genetic diversity are the initial colonization of the continent by anatomically modern humans (AMH), the last glacial maximum, and the Neolithic transition. For some decades it was assumed that the geographical structuring of genetic diversity within Europe was mainly the result of gene flow during and soon after the Neolithic transition, but recent advances in next-generation sequencing (NGS) technologies, computer simulation modeling, and ancient DNA (aDNA) analyses are challenging this simplistic view. Here we review the current knowledge on the evolutionary history of humans in Europe based on archaeological and genetic data.

Link

utorak, 3. srpnja 2012.

Assessing Neolithic Europeans with 'weac2'

Saharan dairying 7,000 years ago



Pottery shards put a date on Africa’s dairying
Yoghurt may have made it on to the menu for North Africans around 7,000 years ago, according to an analysis of pottery shards published today in Nature1.

The fermented dairy product left tell-tale traces of fat on the ceramic fragments, suggesting a way that the region’s inhabitants may have evolved to tolerate milk as adults.

The same team had previously identified the earliest evidence for dairying in potsherds nearly 9,000 years old from Anatolia2. But the findings from 7,000 years ago still predate the emergence and spread of the gene variants needed for the adult population to digest the lactose found in milk, says biomolecular archaeologist Richard Evershed of the University of Bristol, UK, who led the study with archaeological scientist Julie Dunne. He suggests that making yoghurt may have made dairy products more digestible.
Related: Earliest evidence for milk in the Near East and Southeastern Europe

Nature 486, 390–394 (21 June 2012) doi:10.1038/nature11186

First dairying in green Saharan Africa in the fifth millennium bc 

Julie Dunne et al.

In the prehistoric green Sahara of Holocene North Africa—in contrast to the Neolithic of Europe and Eurasia—a reliance on cattle, sheep and goats emerged as a stable and widespread way of life, long before the first evidence for domesticated plants or settled village farming communities1, 2, 3. The remarkable rock art found widely across the region depicts cattle herding among early Saharan pastoral groups, and includes rare scenes of milking; however, these images can rarely be reliably dated4. Although the faunal evidence provides further confirmation of the importance of cattle and other domesticates5, the scarcity of cattle bones makes it impossible to ascertain herd structures via kill-off patterns, thereby precluding interpretations of whether dairying was practiced. Because pottery production begins early in northern Africa6 the potential exists to investigate diet and subsistence practices using molecular and isotopic analyses of absorbed food residues7. This approach has been successful in determining the chronology of dairying beginning in the ‘Fertile Crescent’ of the Near East and its spread across Europe8, 9, 10, 11. Here we report the first unequivocal chemical evidence, based on the δ13C and Δ13C values of the major alkanoic acids of milk fat, for the adoption of dairying practices by prehistoric Saharan African people in the fifth millennium BC. Interpretations are supported by a new database of modern ruminant animal fats collected from Africa. These findings confirm the importance of ‘lifetime products’, such as milk, in early Saharan pastoralism, and provide an evolutionary context for the emergence of lactase persistence in Africa.

Link

BEAN – Bridging the European and Anatolian Neolithic



The BEAN project has been on my radar for a while now, and it's great that it seems to be alive and well. Hopefully it won't be too long until it starts producing results.

The origins of human settlement: Mainz University coordinates a new EU project for young researchers
Junior researcher Zuzana Fajkošová passes international selection procedure and begins her doctorate in the Palaeogenetics Group at the JGU Institute of Anthropology

27.06.2012

"BEAN – Bridging the European and Anatolian Neolithic" is the name of a new multinational educational network which has received funding from the European Commission for the next four years. It is classified as a so-called Initial Training Network (ITN) in the EU Marie Curie Actions program, which allows young scientists early access to research activity at top international institutions. A basic requirement for funding is that the researchers involved leave their home country and conduct their research in another European country.

The BEAN Network consists of several European partners in England, Switzerland, France, Germany, Serbia, and Turkey, and has set itself the goal of enhancing the skills of a new generation of researchers in the subjects of anthropology, pre-history, population genetics, computer modeling, and demography. Many different disciplines are participating in the initiative. An important associate partner on the German side is the German Federal Statistical Office in Wiesbaden. The common focus of the project partners centers around questions associated with the origin of first farmer settlements, which were established some 8,000 years ago in West Anatolia and the Balkans. Where did they come from? Were they migrants from the Middle East? Are they our ancestors? 

Anthropologists at Johannes Gutenberg University Mainz (JGU) have been meticulous in their preparation of the project over the last years and have entered into various cooperations to underpin it. Seven research institutions and two commercial companies are now working together on the BEAN project. Two leading researchers serve the network in an advisory capacity. These are archaeologist Ian Hodder from Stanford, who established his reputation with his excavations in Catal Höyük, and Hermann Parzinger, President of the Prussian Cultural History Foundation, who spent many years excavating and researching in European Turkey.

As of July 2012, doctoral candidate Zuzana Fajkošová, who completed her undergraduate studies at Masaryk University in Brno and at Charles University in Prague in the Czech Republic, will be the first of two BEAN researchers to start work at JGU's Institute of Anthropology and in the new palaeogenetic laboratory, which is currently in the final stages of construction on the edges of the university's Botanic Garden. She will analyze DNA from the bones of the last hunter-gatherers and the first settled farmers in the region between West Anatolia and the Balkans using the new cutting-edge technology of Next Generation Sequencing (NGS). Together with her colleagues in Dublin, London, and Geneva, she will use the genomic data to compile a model for the settlement of Europe.

"It is both a great honor and a huge opportunity for me that I can work together with such renowned researchers. I'm looking forward to Mainz, the university and the institute's new building," comments Fajkošová, who turned down a number of other offers in order to work at JGU. "A major factor leading to her appointment was the fact that besides mastering biomolecular techniques she also has good programming skills,” explains Professor Dr. Joachim Burger, the Network Coordinator. "A few years ago we more or less founded the discipline of Neolithic Palaeogenetics single-handedly. However, undertaking genomic projects is possible only with the help of international colleagues. That is why we are so pleased that such networks give us and our colleagues the chance to train young research talents."

Besides academic training, the young researchers will be able to do practical work for the two commercial companies within the network and thereby gain work experience in a non-university environment. "This is important as not all of the candidates will opt for a pure research career," explains Karola Kirsanow, who moved from Harvard to Mainz last year and now administrates the network together with Burger. "Our young colleagues have to attend many workshops, courses, and internships, most of them abroad. While this makes for a very tough program, we believe that it significantly enhances the quality of the training and similarly enhances candidates' career prospects."