A physico-anthropological study of skeletal material from Neolithic age to Hellenistic times in Central Greece and surrounding region

I have located the text of George Panagiaris important 1993 doctoral thesis on Greek skeletal material. This may be one of the most comprehensive efforts to study the Ancient Greek population from a physical anthropological perspective (413 male and 354 female crania, using 65 biometric characters as well odontological traits).

Panagiaris' conclusions in English can be found in p.10 of the document. He confirms that the greater period of discontinuity in the material is observed during the Helladic period (=Bronze Age in Greek archaeology), where broad-headed incoming groups appear, side by side with the older Mediterranean population. He attributes this to the arrival of such people from the highlands Pindos range, although he sees the possibility of Anatolian influences as well, but has no comparative data. He cites the tendency for broader skulls in higher latitudes, although this general trend in H. sapiens probably does not explain the local trend within Caucasoids where the key difference is between mountaineers (where the Alpine, Dinaric, Armenoid, and Pamir-Ferghana types are well-represented) and lowland folk. Perhaps, if various ancient DNA projects manage to study some Greek material we may be able to ascertain the events that were taking place in Greece at that time.


Of course, the issue cannot be seen in isolation, because at this time we see an increase in brachycephalic types in Crete and Anatolia, the appearance of the intrusive brachycephalic Bell Beaker folk in Western Europe, and perhaps even the presence of the interfluvial type (Pamir-Ferghana type) in the eastern Saka. 

Personally, I see something important in these developments: why would broad-headed mountaineers make their appearance in the lowlands at this time in history? I am strongly leaning towards the idea that this has to do with metallurgical innovation during this time. According to Roberts et al. (2009), from which the figure on the left is taken:

Metallurgy in Eurasia originated in Southwest Asia due to the widespread adoption of, and experimentation in, pyrotechnology and the desire for new materials to serve as aesthetic visual displays of identity, whether of a social, cultural or ideological nature. This can be demonstrated through the early use of metal for jewellery and the use of ore-based pigments along with the continued use of stone, bone, and other materials for most tools. The subsequent appearance of metals throughout Eurasia is due to the acquisition of metal objects by individuals and communities re-inventing traditions of adornment, even in regions hundreds of kilometres from the nearest sources of native metals or ores. The movement of communities possessing metallurgical expertise to new ore sources and into supportive societies led to the gradual transmission of metallurgy across the Eurasian landmass. By the second millennium BC, metallurgy had spread across Eurasia, becoming firmly rooted in virtually all inhabitable areas (Sherratt 2006). The ability to smelt different ores, create different metals or increase metal production did not occur in a linear evolutionary fashion throughout Eurasia, but rather appeared sporadically over a vast area – a result of regional innovations and societal desires and demands. 

There is no evidence to suggest that metallurgy was independently invented in any part of Eurasia beyond Southwest Asia. The process of metallurgical transmission and innovation created a mosaic of (frequently diverse) metallurgical traditions distinguished by form, composition and production techniques. It is within this context that innovations such as the earliest working of gold in the Balkans or the sudden emergence of distinctive tin-bronze working in Southeast Asia should be seen. 

The richest ore deposits were found in mountain areas as Thornton (2009) makes clear:

Models for the development of metallurgy in Southwest Asia have for a long time been focussed on research carried out in the lowland regions of the Levant and Mesopotamia. These models do not take into account the different developmental trajectories witnessed in the resource-rich highlands of Anatolia, the Caucasus, and Iran. In this paper, the beginnings of the use and production of metals in Iran will be juxtaposed with a cursory overview of the lowland model (the ‘Levantine Paradigm’) in order to highlight these differences. By synthesizing data from a number of current research projects exploring the early metallurgy of the Iranian Plateau, this paper demonstrates how at least one of the highland regions of Southwest Asia was at the very forefront of technological innovation from the seventh through the second millennium BC.  

I had planned to write a separate post on the interplay between metallurgy and the rise in social complexity that led to the spread of (at least some branches of-) Indo-European and Semitic during time, but this is probably as good a place as any to summarize the argument:

The practice of metallurgy launched the first globalization: in order to produce high quality metal objects, one needed a variety of specialized workers: prospectors, miners, metalworkers. The necessary ores do not occur everywhere on the map, and production requires a complex logistic operation to manage resources and talent. One needed, in addition, to establish a network of traders and warriors to carry out and supervise the trade, since demand for metal objects was wide and not limited to the vicinity of their production.

Production and trade networks facilitated the flow of ideas, and necessitated the flow of peoples, both because expertise was non-local, and also because the producers wanted to supervise their profitable business. There is an advantage to being an early adopter of new technology; many of the shifts in power in world history depended on a technology differential (European guns in the New World, mounted archers on the Eurasian steppe, triremes in the Mediterranean, Macedonian long-spears vs. Persian light infantry being some examples).

The technology differential eventually dissipates as everyone gets access to the new inventions. This process may take several centuries, but in the meantime those monopolizing them enjoy a triple advantage:

1. There is demand for their product
2. They have the better weapons
3. They are part of broader communities that can muster resources against anyone who crosses them

It is no accident that the Bronze Age started with technological innovation and ended up in a series of military conflicts. What began as a transformation of Neolithic communities by monopolizing guilds of the bearers of the new technologies ended up with everyone having access to them, and of course they went to war.

Getting back to the topic of Panagiaris' dissertation, I might try my hand at translating some interesting portions. These will be posted as updates in the space below.

Clarifying the phylogeny of Y-chromosome haplogroup C3c

A short and to the point paper that addresses the issue of classification within Y-haplogroup C3c and refines our knowledge about the distribution of both C3c* and C3c1. I wish more researchers would publish such short technical papers that refine the classification of their Y-chromosome samples as more phylogenetic information becomes available.

From the paper:

In our study, the highest frequencies of subhaplogroup C3c1-(M77, M86) were observed in Tungusic-speaking people of North-Eastern Asia, such as Evens and Evenks, as well as in Turkic-speaking Altaian Kazakhs and Mongolic-speaking Kalmyks. These results are in agreement with previous observations based on separate or joint genotyping of M77 and M86 markers.3,9,12,16

C3c* haplotypes were detected in aboriginal populations of North- Eastern Asia—Koryaks (28.2%) and Evens (1.6%) from the Sea of Okhotsk coast (Magadan region) and West Evenks (2.4%) from Central Siberia (Evenki Autonomous District) (Table 1). Earlier, two Evenk individuals from southern part of Yakutia, one Yakut-speaking Evenk and one Yukaghir were found to belong to C3c*.2,3 Therefore, the geographic distribution of subhaplogroup C3c* is limited to the eastern part of Siberia.

The authors apply the evolutionary mutation rate -although they acknowledge that molecular dating is controversial- to obtain ages of 9.9 (C3c), 6.5 (C3c1), and 4.5 (C3c*). While I don't trust the ability of Y-STR-based molecular dating to provide reasonably accurate age estimates, I would not be surprised if C3c1 was somehow implicated in the deeper origins of the Altaic language family, at least in the "narrow-sense" (Mongolian-Tungusic-Turkic).

J Hum Genet. 2012 Jul 19. doi: 10.1038/jhg.2012.93. [Epub ahead of print]

On the Y-chromosome haplogroup C3c classification.

Malyarchuk BA, Derenko M, Denisova G.

Abstract As there are ambiguities in classification of the Y-chromosome haplogroup C3c, relatively frequent in populations of Northern Asia, we analyzed all three haplogroup-defining markers M48, M77 and M86 in C3-M217-individuals from Siberia, Eastern Asia and Eastern Europe. We have found that haplogroup C3c is characterized by the derived state at M48, whereas mutations at both M77 and M86 define subhaplogroup C3c1. The branch defined by M48 alone would belong to subhaplogroup C3c*, characteristic for some populations of Central and Eastern Siberia, such as Koryaks, Evens, Evenks and Yukaghirs. Subhaplogroup C3c* individuals could be considered as remnants of the Neolithic population of Siberia, based on the age of C3c*-short tandem repeat variation amounting to 4.5±2.4 thousand years.

Link

Admixture matters

Until recently, tree models dominated models of human demography. Under such models, populations split off from each other in a branching pattern. African populations, and especially African hunter-gatherers, which are the most divergent occupy the basal positions in the tree. The story has been repeated many times: Africans are more genetically diverse, Eurasians carry a subset of African genetic variation, a small subset of Africans left the continent and colonized the world after going through a severe bottleneck and so on.

It's a simple and attractive story, but one which is wholly dependent on ignoring admixture. There are two types of admixture that are pertinent: one is admixture between modern human groups. An example of this is Ethiopia. Many studies have presumed to identify a signal of Out-of-East Africa based on diminishing distance from East Africa. But it is completely unclear how this model fares when one takes into account that East Africans are a recently admixed population: their great genetic diversity may be due to the recent intermingling of two very divergent groups of people (Caucasoids and aboriginal East Africans).

Or, consider two Englishmen, one with a Nigerian and another with a Chinese grandparent. These two individuals might appear greatly diverged from each other genetically and phenotypically, but this is the aggregate of sharing 3/4 of quite recent common ancestry (from their English grandparents), and not sharing 1/4 each of highly divergent ancestry (from their Chinese and Nigerian ones).

The situation is more interesting when we realize that admixture can occur not only between modern human groups, but also between modern humans and archaic ones. Both archaic genomes published so far (Neandertal and Denisova) show differential affiliation to modern human groups, and indirect evidence suggests that some African groups also admixed with archaic species that once lived in Africa.

Of course, levels of archaic admixture inferred from these studies are usually small, but we must remember that a little archaic goes a long way. This is due to the fact that modern humans and archaic ones diverged from each other a long time ago. Their admixture, even in highly favorable (for modern humans) proportions introduces a substantial amount of new genetic variation. As a result, populations harboring archaic admixture appear more divergent from each other.

This point is made quite well in a new article:

If human populations do not all have the same level of archaic introgression, the current genetic structure of human populations might be partly shaped by differential admixture. Estimates of population sizes and divergence times between human populations should thus be affected by past admixture events. The divergence time between an admixed and a non-admixed population should be overestimated if admixture is not properly modelled. Similarly, the effective size of admixed populations should be overestimated as archaic lineages inflate genetic diversity. In Figure 2, we report a simulation study of this bias in a very simple case of population divergence without migration. The overestimations of divergence time and admixed population size are almost linearly increasing with admixture rate (Figure 2). For instance, a divergence time of 1,600 generations (40,000 y assuming a 25-y generation time) is perfectly recovered if none of the populations is admixed, but is overestimated by 100 generations (2,500 y) with 1% admixture in one population, and already by 350 generations (8,750 y) with 5% admixture. Even though our simulated scenario is unrealistically simple, it is likely that differential admixture should affect population genetic affinities under more complex models of population differentiation. The proper interpretation of human genetic affinities should thus probably be re-evaluated in the light of these results. In particular, the divergence between Africans and Oceanians (showing up to 5% archaic admixture [16]) could be more recent than previously reported (62–75 Kya [24]). It remains unclear whether the method used by Rasmussen et al. [24] to date this divergence is also sensitive to differential introgression, but, if that was the case, the colonization wave to Oceania thought to well predate that towards East Asia [24] could have occurred at roughly the same time once differential admixture had been taken into account.

This is an important point: the inferred early dispersal of Oceanians could in fact be the result of archaic admixture in both Africans and Oceanians. 


Lower levels of archaic admixture are sufficient to make two individuals or populations appear much more distant from each other. Archaic Homo populations may be as much as an order of magnitude more divergent to H. sapiens that particular H. sapiens groups are to each other.

But, admixture can also deflate divergence, if there is subsequent gene flow between the diverged populations. As an example, Near Eastern Arab populations: have both diverged from Europeans due to receiving African admixture, and also converged with them by the fact that Europeans have Neolithic Near Eastern admixture which renewed bonds between Europe and the Near East. It means little to speak of "when" Europeans and Near Eastern people diverged from each other: it's a balancing act of centrifugal and centripetal influences: if a Crusader lands on the Levant and marries a local woman, he diminishes apparent Europe-Near East genetic divergence; if a Somali does the same, he increases it. So, in the end, the apparent "divergence" between Europe and the Near East may have little to do with how much time has transpired since the colonization of a new region, and more to do with "who had sex with whom" in the intervening period.

In fact, the ability of admixture to "converge" populations is the basis of the multi-regional evolution theory, although that is usually posited in terms of gene flow. But, the basic idea is still the same: our relatively uniform human species may not be entirely the result of tree-like divergence of populations from an original African population, but rather of a confluence of streams of ancestry derived from Lower and Middle Paleolithic populations of Homo.

Admixture may not only lead us to overestimate divergence between populations: it might lead us to wrongly estimate the directionality of migration itself. 

Consider a future geneticist, working thousands of years after a collapse of civilization in the near future which led into a breakdown of long-distance travel. Such a scientist would perhaps conclude that the highest genetic diversity is to be found in North America, and conclude that North America colonized the rest of the world.

In some cases, it can well be argued that serial founder effects/bottlenecks restrict genetic variation/effective size. For example, the colonization of the Americas in three waves created a population that is clearly a subset of the East Eurasian parental population. But, notice that researchers trying to understand it had to carefully disentangle the various migration waves and cleanse their data from recent European admixture. The directionality of migration can be recovered through a diligent treatment of the evidence.

But, let's forget about the nested-subset analogy: the fact that a population X may appear to be a subset of another Y does not indicate that Y founded X any more than the fact that the genetic variation of any single European country is a subset of the cosmopolitan populations of the Americas will indicate an America-to-Europe migration to the future geneticist. Sometimes, X is a subset of Y because Y has a superset of variation formed by union with a divergent other population.

Sub-Saharan Africa is one example of a terra incognita for the historian. In the absence of written sources, science is mostly clueless as to what was going on there for thousands of years after the invention of writing in Mesopotamia. In some areas, due to the moist climate/abundant vegetation/political instability even archaeological evidence is lacking. What this means is that we are in the dark about what admixtures were going in the Dark Continent. Thankfully, people are working on it.

My own position is that while an origin of anatomically modern humans in Africa still seems to be correct, the pattern of divergence and reduced effective size of Eurasians from Africans is not wholly due to a small group of them leaving the continent at some Middle Pleistocene epoch.

How much of the African divergence and higher African effective population size is due to a Biblical-level bottlenecks coinciding with Out-of-Africa? As readers of the blog know, I don't buy the recent Out-of-Africa model, especially in its "endangered but crafty tribe of pioneers following the coast 60,000 years ago" variety. Archaic admixtures in Eurasia and Africa inflate divergence times; back-migration may deflate them. It's yet another balancing act.

Hopefully statisticians, with a little help from archaeology and palaeoanthropology can untangle the palimpsest of events and present us with a believable story about our own origins. It's time to give up trees and embrace networks!


PLoS Genet 8(7): e1002837. doi:10.1371/journal.pgen.1002837

Genomic Data Reveal a Complex Making of Humans

Isabel Alves et al.

In the last few years, two paradigms underlying human evolution have crumbled. Modern humans have not totally replaced previous hominins without any admixture, and the expected signatures of adaptations to new environments are surprisingly lacking at the genomic level. Here we review current evidence about archaic admixture and lack of strong selective sweeps in humans. We underline the need to properly model differential admixture in various populations to correctly reconstruct past demography. We also stress the importance of taking into account the spatial dimension of human evolution, which proceeded by a series of range expansions that could have promoted both the introgression of archaic genes and background selection.

Link

Redating of the Early Upper Paleolithic site of Riparo Mochi (Italy)

There are two possibilities on how the early Aurignacian entered Europe. According to one hypothesis, its bearers followed the Danube, which formed a natural corridor into the heartland of the continent which was, at the time, thickly forested. A different hypothesis is that the early Aurignacian entered Europe via the Mediterranean. Distinguishing between the two hypotheses depends on obtaining reliable chronological estimates for the Mediterranean and Central European Aurignacian

A recent dating of a site in the Swabian Jura suggested that the Aurignacian was earlier attested in Central Europe. But, another paper in the Journal of Human Evolution examines meticulously the sequence in the Moch rockshelter and finds that it is just as early.

Comparisons with dates for other Upper Palaeolithic contexts outside Italy suggest that the date of the Protoaurignacian of Mochi compares closely. In Fig. 9a the start boundaries for the earliest Aurignacian evidence at the sites of Geissenklösterle (Germany), Abri Pataud and Isturitz (France) are compared to the start boundary for unit G in Mochi. The first two sites were dated recently in Oxford with reliable methodologies (Higham et al., 2011; Higham et al., in press) while for Isturitz only a small number of dates exist for the earliest Upper Palaeolithic (Szmidt et al., 2010). This comparison reveals that the lowermost Aurignacian levels at Geissenklosterle (AHIII) and Isturitz (C4d) date to the same period as Mochi G, at around 42.7-41.5 ka cal BP (68.2%). The earliest Aurignacian of Abri Pataud dates slightly later to around 41e40 ka cal BP (68.2%), but the assemblage there has always been considered more evolved, so this is not surprising. No Mousterian dates are included in any of these calculations, therefore the start boundaries in the Bayesian models are not well constrained at their earliest end. What is interesting is that there appears to be a close similarity between the dates for the Protoaurignacian and Early Aurignacian sites in Germany on the Danube and on the Mediterranean coast. This might suggest a rapid dispersal of both variants of the Aurignacian across Europe at c. 44-42 ka cal BP.

It does appear that the Aurignacian was a continent-wide punctuational event in Europe which occurred in the middle to late 40 thousands ka cal BP.

Either there were two streams into Europe (Danubian and Mediterranean), or one stream that quickly inundated much of the continent. Given that the argument for the Danubian Corridor is partly related to the ease of access it provided, it is difficult to imagine how the people who followed it would quickly stray far from it all the way to Italy. Overall, it does appear that there were multiple streams into Europe, and perhaps new research in the Balkans, Eastern Europe, and West Asia, may help us trace the earlier predecssor of these streams before they followed their separate ways into Europe.

Journal of Human Evolution DOI:10.1016/j.jhevol.2011.11.009

A new chronostratigraphic framework for the Upper Palaeolithic of Riparo Mochi (Italy)


Katerina Douka et al.


The rockshelter of Mochi, on the Ligurian coast of Italy, is often used as a reference point in the formation of hypotheses concerning the arrival of the Aurigancian in Mediterranean Europe. Yet, the site is poorly known. Here, we describe the stratigraphic sequence based on new field observations and present 15 radiocarbon determinations from the Middle Palaeolithic (late Mousterian) and Early Upper Palaeolithic (Aurignacian and Gravettian) levels. The majority of dates were produced on humanly modified material, specifically marine shell beads, which comprise some of the oldest directly-dated personal ornaments in Europe. The radiocarbon results are incorporated into a Bayesian statistical model to build a new chronological framework for this key Palaeolithic site. A tentative correlation of the stratigraphy to palaeoclimatic records is also attempted.

Link

Huge study on Y-chromosome variation in Iran (Grugni et al. 2012)

This is the equivalent of a box of candy for anyone interested in Eurasian (pre-)history. I will have digest all the goodies within, and post any of my comments as updates to this post.

UPDATE I: Here is the table of haplogroup frequencies for easy reference:

One of the most interesting finds is the presence of a few IJ-M429* chromosomes  in the sample. Haplogroup IJ encompasses the major European I subclade, and the major West Asian J subclade. The discovery of IJ* chromosomes is consistent with the origin of this haplogroup in West Asia; it is widely believed that haplogroup I represents a pre-Neolithic lineage in Europe, although at present there are no Y chromosome-tested pre-Neolithic remains.

There is also a wide assortment of Q and R in Iran. While some of these may be intrusive (e.g., the 42.6% of Q1a2 in Turkmen, likely a legacy of their Central Asian origins), the overall picture appears consistent with a deep presence of these lineages in Iran. This is especially true for haplogroup R where pretty much every paragroup and derived group is present, excepting those likely to have originated recently elsewhere.

UPDATE II: From the paper:

Although accounting only for 25% of the total variance, the first two components (Figure 3) separate populations according to their geographic and ethnic origin and define five main clusters: East-African, North-African and Near Eastern Arab, European, Near Eastern and South Asian. The 1stPC clearly distinguishes the East African groups (showing a high frequency of haplogroup E) from all the others which distribute longitudinally along the axis with a wide overlapping between European and Arab peoples and between Near Eastern and South Asian groups. The 2ndPC separates the North-African and Near Eastern Arabs (characterized by the highest frequency of haplogroup J1) from Europeans (characterized by haplogroups I, R1a and R1b) and the Near Easterners from the South Asians (due to the distribution of haplogroups G, R2 and L). Iranian groups do not cluster all together, occupying intermediate positions among Arab, Near Eastern and Asian clusters. In this scenario, it is worth of noticing the position of three Iranian groups: (i) Khuzestan Arabs (KHU-Ar) who, despite their Arabic origin, are close to the Iranian samples; (ii) Armenians from Tehran (THE-Ar), whose position, in the upper part of the Iranian distribution, indicates a close affinity with the Near Eastern cluster, while their position near Turkey and Caucasus groups, due to the high frequency R1b-M269 and other European markers (eg: I-M170), is in agreement with their Armenia origin; (iii) Sistan Baluchestan (SB-Ba) that clusters with its neighbouring Pakistan.

UPDATE III: There are lots of little details in the haplogroup distribution that make historical sense. For example, C3 exists in Assyrians from Azarbaijan, and both C*, C3, and O exists in Zoroastrians from Yazd. It is often forgotten that before the spread of Islam, and quite time thereafter, Inner Asia was teeming with Zoroastrians and Nestorian Christians. It seems quite likely that these outliers represent a legacy of these communities.

UPDATE IV: I have a feeling that Razib will take exception with this statement: "Ancient Persian people were firstly characterized by the Zoroastrianism. After the Islamization, Shi'a became the main doctrine of all Iranian people."


UPDATE V: This confirms my observation from the recent studies in Afghanistan, that there is an inverse relationship of J2a and R1a in Iranian-speaking groups, with an excess of the latter among the eastern Iranians, and of the former among the Persians. From the paper:

Among the different J2a haplogroups, J2a-M530 [46] is the most informative as for ancient dispersal events from the Iranian region. This lineage probably originated in Iran where it displays its highest frequency and variance in Yazd and Mazandaran (Figure 2). Taking into account its microsatellite variation and age estimates along its distribution area (Tables S3 and S7), it is likely that its diffusion could have been triggered by the Euroasiatic climatic amelioration after the Last Glacial Maximum and later increased by agriculture spread from Turkey and Caucasus towards southern Europe. The high variance observed in the Italian Peninsula is probably the result of stratifications of subsequent migrations and/or of the presence of sub-lineages not yet identified. Of interest in the M530 network (Figures 2 and S3) is the presence of a lateral branch that is characterized by a DYS391 repeat number equal to 9. Differently from previous observations [46], this branch is not restricted to Anatolian Greek samples being shared with different eastern Mediterranean coastal populations. The M530 diffusion pattern seems to be also shared by the paragroups J2a-M410* and J2a-PAGE55*. In addition, the variance distribution of the rare R1b-M269* Y chromosomes, displaying decreasing values from Iran, Anatolia and the western Black Sea coastal region, is also suggestive of a westward diffusion from the Iranian plateau, although more complex scenarios can be still envisioned because of its non-star like structure.

Of course, the idea that the diffusion of J2a related lineages ties in with early agricultural expansions has been with us for a long time, but it is time to abandon it. First of all, as we have seen, J2a diminishes greatly as we head towards South Asia; it certainly doesn't look like the lineage of the multitude of agricultural settlements that sprang up along the southeastern vector soon after the invention of agriculture. Second, it is lacking so far in all ancient Y chromosome data from Europe down to 5,000 years ago. It seems much more probably that J2 related lineages spread from the highlands of West Asia much later. 


The "age estimates" are the result of using the inappropriate "evolutionary mutation rate", and become even older because of the inclusion of the DYS388 marker that is very stable in many haplogroups but very mutable within haplogroup J. On the left you can see frequency, Y-STR variance, and haplotype network structures for various J-related groups.


It is unfortunate that there is no progress in the phylogeographic assessment of R1a in this paper. There have been substantial discoveries of SNPs within this haplogroup as a result of commercial testing; however there is clearly an ascertainment bias in the newer discoveries, as almost all these SNPs have been detected in Europeans. The new paper confirms the high levels of Y-STR variance in India, Pakistan, and Iran. Together with the cornucopia of related paragroups in Iran, there is little doubt that this haplogroup originated in the general area of Central/South Asia.


Personally, as I have stated before, I would relate this R1a with Neolithic peoples living east of the Caspian, in contrast to the R1b bearers who lived west and south of it. These two populations came under the influence of the Indo-Europeans and spread in different directions. The Indo-Iranians were then initially the mixed descendants of the Indo-Europeans and the R1a old agricultural population, and were formed in the territory of the Bactria-Margiana Archaeological Complex. 


This also explains the contrast between Iranian and Armenian groups: the latter mostly lack the R1a lineage, contrasting with all Iranian groups (even their Kurdish neighbors) who possess it. Conversely, Iranian groups, and especially eastern Iranians and Indo-Ayrans lack the R1b lineage. This is due to the fact that neither R1a nor R1b were originally part of the Indo-European community, but their geographical position was such that they came under the influence of the Indo-Europeans when the latter began their expansion.


UPDATE VI: I have created my own dendrogram using the Y-haplogroup frequencies and the hclust package of R (default parameters):

From top to bottom, one can identify some clusters:

• Eastern Europe, further broken down into Balkans and Slavic+Hungary
• West Asian/Caucasus
• Iranian Proper
• Arab

These correspond largely to the clusters identified by the authors, with India and the Turkmen sample emerging as the clear outliers. I omitted the Ethiopian samples, since E-M78 was not resolved phylogenetically, causing the Ethiopians to group with the likely E-V13 from the Balkans.

UPDATE VII: I have also run MCLUST over the haplogroup frequency data over the MDS representation of the distance matrix. The maximum number of 10 clusters occurred with 5 MDS dimensions retained. Population assignments in the 10 clusters can be found in the table below:

Iran/Azerbaijan_Gharbi+Tehran_(Assyrian)	1
Iran/Lorestan_(Lur)	1
Iran/Tehran_(Armenian)	1
Iran/Azerbaijan_Gharbi_(Azeri)	2
Iran/Hormozgan_(Bandari+Afro-Iranian)	2
Iran/Hormozgan/Qeshmi	2
Iran/Khorasan_(Persian)	2
Iran/Kurdistan_(Kurd)	2
Iran/Sistan_Baluchestan_(Baluch)	2
Pakistan	2
Iran/Fars+Isfahan_(Persian)	3
Iran/Gilan_(Gilak)	3
Iran/Yazd+Tehran_(Zoroastrian)	3
Turkey/Central	3
Turkey/East	3
Turkey/West_	3
Iran/Golestan_(Turkmen)	4
India	4
Iran/Khuzestan_(Arab)	5
Egypt_(Arab)	5
Iraq/Baghdad	5
Oman	5
Saudi_Arabia	5
Tunisia	5
United_Arab_Emirates	5
Iran/Mazandaran_(Mazandarani)	6
Iran/Yazd_(Persian)	6
Balkarian	6
Georgia	6
Albania	7
Greece	7
Bosnia	8
Croatia	8
Slovenia	8
Czech_Republic	9
Hungary	9
Poland	9
Ukraine	9
Iraq_(Marsh_Arab)	10
Qatar	10
Yemen	10

We can ignore cluster #4 which consists of the two outliers (India + Turkmen). The rest of the clusters seem relatively coherent. Notice, for example, the Arabian cluster #10, Balkan cluster #8, Eastern European cluster #9, Greek-Albanian cluster #7, Mixed Arab cluster #5.

PLoS ONE 7(7): e41252. doi:10.1371/journal.pone.0041252

Ancient Migratory Events in the Middle East: New Clues from the Y-Chromosome Variation of Modern Iranians

Viola Grugni et al.


Knowledge of high resolution Y-chromosome haplogroup diversification within Iran provides important geographic context regarding the spread and compartmentalization of male lineages in the Middle East and southwestern Asia. At present, the Iranian population is characterized by an extraordinary mix of different ethnic groups speaking a variety of Indo-Iranian, Semitic and Turkic languages. Despite these features, only few studies have investigated the multiethnic components of the Iranian gene pool. In this survey 938 Iranian male DNAs belonging to 15 ethnic groups from 14 Iranian provinces were analyzed for 84 Y-chromosome biallelic markers and 10 STRs. The results show an autochthonous but non-homogeneous ancient background mainly composed by J2a sub-clades with different external contributions. The phylogeography of the main haplogroups allowed identifying post-glacial and Neolithic expansions toward western Eurasia but also recent movements towards the Iranian region from western Eurasia (R1b-L23), Central Asia (Q-M25), Asia Minor (J2a-M92) and southern Mesopotamia (J1-Page08). In spite of the presence of important geographic barriers (Zagros and Alborz mountain ranges, and the Dasht-e Kavir and Dash-e Lut deserts) which may have limited gene flow, AMOVA analysis revealed that language, in addition to geography, has played an important role in shaping the nowadays Iranian gene pool. Overall, this study provides a portrait of the Y-chromosomal variation in Iran, useful for depicting a more comprehensive history of the peoples of this area as well as for reconstructing ancient migration routes. In addition, our results evidence the important role of the Iranian plateau as source and recipient of gene flow between culturally and genetically distinct populations.

Link

Crafty El Sidrón Neandertals exploited plants for food and medicine

Neanderthals in Northern Spain Had Knowledge of Plants' Healing Qualities, Study Reveals 

An international team of researchers, led by the Universitat Autònoma de Barcelona and the University of York, has provided the first molecular evidence that Neanderthals not only ate a range of cooked plant foods, but also understood its nutritional and medicinal qualities.

Until recently Neanderthals, who disappeared between 30,000 and 24,000 years ago, were thought to be predominantly meat-eaters. However, evidence of dietary breadth is growing as more sophisticated analyses are undertaken.

Researchers from Spain, the UK and Australia combined pyrolysis gas-chromatography-mass spectrometry with morphological analysis of plant microfossils to identify material trapped in dental calculus (calcified dental plaque) from five Neanderthals from the north Spanish site of El Sidrón.

...

Dr Stephen Buckley, a Research Fellow at the University of York's BioArCh research facility, said: "The evidence indicating this individual was eating bitter-tasting plants such as yarrow and camomile with little nutritional value is surprising. We know that Neanderthals would find these plants bitter, so it is likely these plants must have been selected for reasons other than taste."

... 

The researchers say evidence for cooked carbohydrates is confirmed by both the cracked/roasted starch granules observed microscopically and the molecular evidence for cooking and exposure to wood smoke or smoked food in the form of a range of chemical markers including methyl esters, phenols, and polynuclear aromatic hydrocarbons found in dental calculus.

...

The study also provides evidence that the starch granules reported from El Sidrón represent the oldest granules ever to be confirmed using a biochemical test, while ancient bacteria found embedded in the calculus offers the potential for future studies in oral health.

The archaeological cave site of El Sidrón, located in the Asturias region of northern Spain, contains the best collection of Neanderthal remains found in the Iberian Peninsula and one of the most important active sites in the world. Discovered in 1994, it contains around 2,000 skeletal remains of at least 13 individuals dating back around 47,300 to 50,600 years.

NATURWISSENSCHAFTEN 2012, DOI: 10.1007/s00114-012-0942-0

Neanderthal medics? Evidence for food, cooking, and medicinal plants entrapped in dental calculus

Karen Hardy et al.

Link

Major new ancient DNA project on Southeast Asia and Australia

It seems that I read about a new major project on ancient DNA every other day. There is a lot of activity in this field, which will, no doubt, bear fruit in the coming years.

What I really want to see is a complete genome sequence of early Homo sapiens, e.g., from a sample about as old as Vindija and Denisova. If anyone knows of any such sequencing efforts in the works, write in the comments, or drop me an e-mail.

DNA analysis of ancient remains to uncover origin mysteries
Griffith University leads search for human evolution

In collaboration with the Universities of Auckland, Copenhagen and New South Wales, the researchers will analyse human remains from continental and oceanic Asia and Australia using more powerful newly developed ancient DNA sequencing methods.
Chief Investigator Professor David Lambert from the School of Environment says understanding where the earliest people of Asia and continental Australia came from is critical to understanding modern human evolution.

"The recent sequencing of the Australian Aboriginal genome has identified two waves of human migration through Asia,'' he said.

"Aboriginal Australians descended from an early human dispersal into eastern Asia, possibly 62,000 to 75,000 years ago.

"This dispersal is separate from the one that gave rise to modern Asians 25,000 to 38,000 years ago, although there is evidence for hybridisation between them."

The researchers aim to identify descendent individuals from both lineages and detect historic patterns of interbreeding among these early people.

Professor Paul Tacon from Griffith University's Place, Evolution & Rock Art Heritage Unit said the research was a world-first study to attempt to recover human DNA sequences from more than 80 ancient human remains collected from a range of time points.
"We aim to identify the mitochondrial DNA lineage of each sample of human remains, the migration wave they represented and evidence of biological interactions, such as hybridisation with other groups.

"Although complete or draft genomes have been recovered from extinct species such as Neandertals and Woolly Mammoths, there are no existing populations of these species available for comparison.

"But an increasing number of complete human genomes in our study provide the foundation for this work."

Professor Tacon said the study was possible because of recent advances in second-generation DNA sequencing and parallel developments in DNA target capture technologies.

"These developments provide extraordinary new possibilities in the field of ancient human genomics."

The study is part of a $550,000 three-year Australian Research Council Linkage Grant.

fastIBD over 2,257 Europeans

Razib points me towards a very interesting new paper that applies fastIBD over the large POPRES dataset of Europeans. The most interesting thing about this is that the authors develop techniques for estimating the time depth of the pattern of common ancestry across Europe, and hence are able to conclude that the Slavic expansion has played a bigger role in European history than the Germanic one.

A worthwhile improvement would be to apply a clustering algorithm like I did back in January over the fastIBD output; that way, one does not have to arbitrarily partition Europe into regions, but have the partitions jump out of the data.

A different idea to confirm the scenario presented in this paper would be to drill into different European populations. For example, in the case of the Italians, it would be worthwhile to identify whether there are particular sub-populations with likely Greek or Albanian ancestry who share an excess of IBD with modern Greeks and Albanians.

Population averages may mask such interesting patterns lurking in the data. For example, sub-clusters within populations can be identified with both fineSTRUCTURE and fastIBD, and the corresponding clusters can be assessed with supervised ADMIXTURE to detect how they differ from each other. For example, using this technique, I was able to infer 3 sub-clusters within the ethnic Greek population:

• pop8 (mainland Greek) with ~23% North_European
• pop11 (Greek Cypriot) with ~5% North_European
• pop14 (Cretan, islander, mainland+Asia Minor) with ~12% North_European
• I have also a strong hunch based on a few half Pontic Greek+half mainland Greek data points that unmixed Pontic Greeks would be related to pop22 (Northeastern Anatolia) with ~5% North_European

Based on these results and the fastIBD analysis of Ralph and Coop (the POPRES Greek sample is from northern Greece), it might appear that a hefty portion of the North_European component in Greeks may date to the medieval period, since it is relatively smaller in eastern Greeks and Cypriots and also in the South Italian/Sicilian cluster pop16 of a different analysis, with Italians as a whole lacking the eastern European affiliations of some Greek groups.

Interestingly, ~5% North_European levels would be similar to those of Armenians who are the closest linguistic cousins of the Greeks within the Indo-European family, as well as the the Anatolian Turkish cluster pop13 at ~9%.

Overall, it would appear that some mainland Greek groups received some input as the result of the medieval Slavic intrusions, since the mainland North_European excess appears as a "wedge" within the South Italy/Sicily/Crete/Anatolia/Armenia arc and the fastIBD pattern of sharing suggests that this is due to fairly recent connections.

As I have pointed out before, one limitation of the method of counting shared blocks of ancestry is that it does not disclose the directionality of gene flow. For example, gene flow between Germans and Slavs is detected in this study, which could be ascribed to Germans living in eastern Europe and/or to Slavs becoming acculturated Germans as a result of living within Germanic states or intermarrying with them prior to the age of the nation state.

Finally -and most interestingly- I hope that similar haplotype-based methods can be applied to a wider dataset, because, as it is becoming clear, Europe has not been isolated from Asia or Africa during its long history. The authors mention "Slavic or Hunnic" as an explanation for the pattern of shared ancestry in eastern Europe, but it is only by including Asian groups that we can detect the existence of real Hunnic (or Avar, or Mongol, or Pecheneg, or, ...) ancestry.

Moreover, I am confident that the Bronze Age is well within the power of haplotype-based methods to detect IBD. For example, South Asian populations clearly show differential patterns of affiliation with modern West Eurasian groups, most of which can date to no later than the Bronze Age. Together with the gradual incorporation of the new ancient DNA genomes that are bound to be coming our way soon, it seems that our picture of not only recent history, but also of late prehistory is bound to become much sharper.

arXiv:1207.3815v1 [q-bio.PE]


The geography of recent genetic ancestry across Europe

Peter Ralph, Graham Coop
(Submitted on 16 Jul 2012)

The recent genealogical history of human populations is a complex mosaic formed by individual migration, large-scale population movements, and other demographic events. Population genomics datasets can provide a window into this recent history, as rare traces of recent shared genetic ancestry are detectable due to long segments of shared genomic material. We make use of genomic data for 2,257 Europeans (the POPRES dataset) to conduct one of the first surveys of recent genealogical ancestry over the past three thousand years at a continental scale. We detected 1.9 million shared genomic segments, and used the lengths of these to infer the distribution of shared ancestors across time and geography. We find that a pair of modern Europeans living in neighboring populations share around 10-50 genetic common ancestors from the last 1500 years, and upwards of 500 genetic ancestors from the previous 1000 years. These numbers drop off exponentially with geographic distance, but since genetic ancestry is rare, individuals from opposite ends of Europe are still expected to share millions of common genealogical ancestors over the last 1000 years. There is substantial regional variation in the number of shared genetic ancestors: especially high numbers of common ancestors between many eastern populations likely date to the Slavic and/or Hunnic expansions, while much lower levels of common ancestry in the Italian and Iberian peninsulas may indicate weaker demographic effects of Germanic expansions into these areas and/or more stably structured populations. Recent shared ancestry in modern Europeans is ubiquitous, and clearly shows the impact of both small-scale migration and large historical events. Population genomic datasets have considerable power to uncover recent demographic history, and will allow a much fuller picture of the close genealogical kinship of individuals across the world.

Link

From the earliest modern humans to the onset of farming (45,000-4,500 BP)

This is a very exciting new project led by Ron Pinhasi. Together with the BEAN Project it seems that we are about to get a wealth of new data on many of the topics that are of great interest to readers of the blog.

It does seem that there is a cutoff data of 4,500BP for the scope of the project, which may be a little unfortunate if I'm right about the interesting stuff that was taking place place in Europe during the Bronze Age. But, still, getting plenty of new Y-chromosome, mtDNA, autosomal, and craniometric data for the 40 thousand years or so before that will in no doubt inform debates about more recent events as well.

From the earliest modern humans to the onset of farming (45,000-4,500 BP) January 2011-December 2014

This project which is led by Ron Pinhasi and is carried out in collaboration with leading European scientists, investigates the evolution and nature of major prehistoric processes which are key to our understanding of what happened in European prehistory: the origins and spread of modern humans during the Late Pleistocene, their survival during the last Ice Age, post-glacial expansions, the emergence of the first agricultural societies and the decline and eventual disappearance of most hunter-gatherer societies in Europe.

The focus is on the application of state of the art methods in genetics, archaeological sciences and anthropology which allow our team to address for the first time these major processes in sufficient depth and resolution and to yield new knowledge about the interface between human biology, climate , culture and life style. 

The colonisation of Europe by anatomically modern humans (AMHs) ca. 45,000 years before present (BP) and the transition to farming ca. 8,000 BP are two major events in human prehistory. Both events involved certain cultural and biological adaptations, technological innovations, and behavioural plasticity which are unique to our species. 

The reconstruction of these processes and the causality between them has so far remained elusive due to technological, methodological and logistical complexities.
Major developments in our understanding of the anthropology of the Upper Palaeolithic, Mesolithic and Neolithic, and advances in ancient DNA (aDNA) technology and chronometric methods now allow us to assess in sufficient resolution the interface between these evolutionary processes, and changes in human culture and behaviour. 

The project investigates the complex interface between the morphological, genetic, behavioural, and cultural factors that shaped the population history of European AMHs.  

The approach taken include (a) the collection of bioarchaeological, aDNA, stable isotope (for the analysis of ancient diet) and radiometric data on >700 skeletons from key sites/phases across Eurasia, and (b) the application of existing and novel aDNA, bioarchaeological and simulation methodologies.  

This research will yield results that transform our current understanding of major demographic and evolutionary processes and will place Europe at the forefront of anthropological, biological, and genetic research. 

Blood group of pre-Columbian Peruvian highlanders

AJPA DOI: 10.1002/ajpa.22115

Molecular characterization of ABO blood group frequencies in pre-Columbian Peruvian highlanders

Léa Georges et al.

The majority of Native Americans nearly exclusively belong to group O of the ABO blood group system. Several hypotheses have been formulated to explain this observation, primarily differing by the presumption that the observed patterns of ABO diversity are due to the processes of the initial peopling of the Americas or due to subsequent events, especially the demographic consequences in the wake of European contact. A promising strategy to reveal possible diachronic ABO frequency changes is the molecular genetic analysis of relevant genetic markers in precontact populations. A previous study by Halverson and Bolnick [Am J Phys Anthropol 137 (2008) 342-347] already accomplished this for indigenous North American populations. Here we present the first study to analyze ABO blood types from pre-Columbian individuals from South America using molecular genetic methods and comparing them to several extant South American, North American, and Siberian populations. We tried to determine ABO blood types for 59 individuals from the southern Peruvian highlands dating to ∼650 to 1250 AD using a newly developed multiplex PCR/SBE assay coamplifying the fragments relevant for blood type determination and three highly discriminating autosomal STRs. Analysis was successful for 31 individuals and revealed that all are exclusively in the O group, predominantly carrying the O02 (01v) allele. No significant difference could be observed between the ancient and modern Native American populations, while all significantly differed from the extant Siberian populations, supporting the suggestion that low ABO diversity results from founder effects during the initial peopling of the Americas.

Link

5,300-year-old Mongolian statue

5,300-year-old Mongolian statue pieced back together

ARCHAEOLOGISTS of the Chinese Academy of Social Sciences have finished reconstructing a 5,300-year-old pottery statue from fragments unearthed in North China’s Inner Mongolia Autonomous Region, it was announced Saturday. 

The debris of the pottery statue were found at the Xinglonggou relics site in Aohan Banner of Chifeng City in May. 

Experts began to excavate the debris June 30, and finished restoring the statue on Friday, said Liu Guoxiang, leader of the first archaeology team of Inner Mongolia. 

The restored seated figure is 55cm high with bulging eyes, a high nose and vivid facial expression. It was pieced together from 65 fragments. 

“The statue may be of a wizard or leader in the famous Hongshan Culture period (a Neolithic culture dating back 5,000-6,000 years),” added Liu.

Children of lesbians fare worse than children of heterosexual parents

From a related article in Slate by the author:

The rapid pace at which the overall academic discourse surrounding gay and lesbian parents’ comparative competence has swung—from the wide acknowledgement of challenges to “no differences” to more capable than mom and pop families—is notable, and frankly a bit suspect. Scientific truths are seldom reversed in a decade. By comparison, studies of adoption—a common method by which many same-sex couples (but even more heterosexual ones) become parents—have repeatedly and consistently revealed important and wide-ranging differences, on average, between adopted children and biological ones. The differences have been so pervasive and consistent that adoption experts now emphasize that “acknowledgement of difference” is critical for both parents and clinicians when working with adopted children and teens. This ought to give social scientists studying gay-parenting outcomes pause—rather than lockstep unanimity. After all, many children of gay and lesbian couples are adopted. 

... 

The basic results call into question simplistic notions of “no differences,” at least with the generation that is out of the house. On 25 of 40 different outcomes evaluated, the children of women who’ve had same-sex relationships fare quite differently than those in stable, biologically-intact mom-and-pop families, displaying numbers more comparable to those from heterosexual stepfamilies and single parents. Even after including controls for age, race, gender, and things like being bullied as a youth, or the gay-friendliness of the state in which they live, such respondents were more apt to report being unemployed, less healthy, more depressed, more likely to have cheated on a spouse or partner, smoke more pot, had trouble with the law, report more male and female sex partners, more sexual victimization, and were more likely to reflect negatively on their childhood family life, among other things. Why such dramatic differences? I can only speculate, since the data are not poised to pinpoint causes. One notable theme among the adult children of same-sex parents, however, is household instability, and plenty of it. The children of fathers who have had same-sex relationships fare a bit better, but they seldom reported living with their father for very long, and never with his partner for more than three years.

...

So why did this study come up with such different results than previous work in the field? And why should one study alter so much previous sentiment? Basically, better methods. When it comes to assessing how children of gay parents are faring, the careful methods and random sampling approach found in demography has not often been employed by scholars studying this issue, due in part—to be sure—to the challenges in locating and surveying small minorities randomly. In its place, the scholarly community has often been treated to small, nonrandom “convenience” studies of mostly white, well-educated lesbian parents, including plenty of data-collection efforts in which participants knew that they were contributing to important studies with potentially substantial political consequences, elevating the probability of something akin to the “Hawthorne Effect.” This is hardly an optimal environment for collecting unbiased data (and to their credit, many of the researchers admitted these challenges). I’m not claiming that all the previous research on this subject is bunk. But small or nonrandom studies shouldn’t be the gold standard for research, all the more so when we’re dealing with a topic so weighted with public interest and significance.

Social Science Research Volume 41, Issue 4, July 2012, Pages 752–770

How different are the adult children of parents who have same-sex relationships? Findings from the New Family Structures Study

Mark Regnerus

The New Family Structures Study (NFSS) is a social-science data-collection project that fielded a survey to a large, random sample of American young adults (ages 18–39) who were raised in different types of family arrangements. In this debut article of the NFSS, I compare how the young-adult children of a parent who has had a same-sex romantic relationship fare on 40 different social, emotional, and relational outcome variables when compared with six other family-of-origin types. The results reveal numerous, consistent differences, especially between the children of women who have had a lesbian relationship and those with still-married (heterosexual) biological parents. The results are typically robust in multivariate contexts as well, suggesting far greater diversity in lesbian-parent household experiences than convenience-sample studies of lesbian families have revealed. The NFSS proves to be an illuminating, versatile dataset that can assist family scholars in understanding the long reach of family structure and transitions.

Link

The theory that won't die: Chris Stringer on Modern Human Origins

I devoted a whole post on the topic recently, so I won't repeat myself. I'll just say that if modern human behavior evolved in Africa and it was this which facilitated the spread of humans into Eurasia ~60,000 years ago, then they forgot to leave behind any evidence for it.

A Bone Here, a Bead There: On the Trail of Human Origins

There were remarkable things happening in Europe at least 40,000 years ago, with the painted caves, with flutes, with the statuettes and so on. But the seeds of that revolution were sown in Africa more than 100,000 years ago. I would argue that when modern humans came out of Africa, say 60,000 years ago, fundamentally they were behaviorally modern. They took that into Europe. They took that into Asia and into Australia. So there was no single revolutionary event in Europe; this was something that was in modern humans when they came out of Africa, and the ones who stayed behind as well.

The following quote by mousterian is worth highlighting:

What we are dancing around here is an issue more fundamental than simply coastal vs. interior, early vs. late. If it was an expansion (or wave of expansions) during MIS 5 through the interior, these are hunter-gatherers tracking a known ecosystem. If a late expansion during MIS 4 or early MIS 3 along the coast, these represents some innovative cultural adaptation that has enabled them to exploit a new ecosystem and rapidly disperse through it (i.e. the rim of the Indian Ocean). In other words, were we lucky hunter-gatherers in the right place at the right time during the Last Interglacial, or crafty beachcombers struggling for survival across the post-apocalyptic post-Toba landscape? Pushed out of Africa, or pulled into Arabia? In my mind, this is the real disparity between the two models.

Interestingly, all of the Palaeolithic archaeologists working in Arabia unanimously agree on the "lucky hunter-gatherers" MIS 5 scenario. Granted, it’s not as sexy as believing we are somehow fundamentally different, new, and improved. That’s the problem with fact versus fiction.

My chips are on the "lucky hunter-gatherers" MIS 5 scenario and I'm sticking to it until I see any evidence for behaviorally modern people in East Africa or Arabia or the Levant at the time of the postulated 60ky-old migration. But, it's good to see both positions vigorously argued.

Late Minoan IB destructions not followed by Mycenaean immigration

This is an important contribution which falsifies the theory that the destructions of the Minoan palaces associated with the Late Minoan IB involved the coming of Mycenaean elites to Crete, by using a combination of strontium isotope analysis (which captures first-generation migrants) and biodistance analysis (which reveals no pattern of greater affinity of post-LMIB populations to mainland Greek samples.

However, this is interesting:

Therefore these results suggest a gradual rounding of the cranial shape for the Central Cretan population in the course of the Bronze Age, resulting from the increase of the cranial breadth in relation to cranial length. They further provide negative evidence for a disruption of the biological history of the Knossos population following the LMIB destructions due to an increase in the biodistance between the samples dating immediately prior and following the destructions.  

The gradual rounding of the cranial shape of the Central Cretan population over the course of the Bronze Age and the very similar shape of the Gypsades, Sellopoulo and Mavrospelio crania can be more clearly appreciated by plotting the Cranial Index (100*maximum cranial breadth/glabello – occipital length) data. The Cranial Index describes the cranial shape and higher cranial indices reflect a more rounded cranium. In Figure 7, the Cranial Indices for all the above-mentioned Central Cretan population samples are plotted in chronological order, from the Early to Late Bronze Age. Cranial Indices were calculated separately for males and females from each sample.  

The gradual increase in Cranial Index over the Bronze Age most probably reflects gene-flow from population/s biologically different from the Early Bronze Age Cretan population and from inter-population biological interactions (admixture) in the succeeding periods. An alternative interpretation implicating the thermoregulatory model of Beals et al. (1984) and adaptation to colder climatic conditions carries less weight. 

This might be consistent with J. Lawrence Angel's detection of a "Dinaroid-Alpine central trend" of Bronze Age invaders of Greece, as well as the well-known contemporary physiognomy of the historical Hittites and the physical anthropological evidence for them:

Senyurek (1951d, pp. 614-15) concludes that "the majority of the Chalcolithic and Copper Age inhabitants of Anatolia were dolichocephals of mainly Eurafrican and Mediterranean types, and that the brachycephals, probably representing the invaders, were rare in these periods. This study has further supported the conclusion that the earliest inhabitants of Anatolia were longheaded, and that the brachycephals came in subsequently. "The craniological evidence indicates that an invasion of brachycephals into Anatolia took place during the Chalcolithic period and that it was followed by a second invasion, bringing in the brachycephalic elements to Alaca Huyuk and other Copper Age sites, probably at about the middle of the Copper Age. The next invasion of brachycephals, which was more important and extensive than the previous ones, occurred at about 2000 B.C. This was made by the Hittites who were predominantly of the classical Alpine type."  

While there does not appear to be specific evidence for a new population element arriving in Crete after the LMIB destructions, the pattern during the Bronze Age is probably consistent with an intrusive population.

If we accept that the European Neolithic island-hopped to Greece from the East and thence spread north and east into Europe, it is peculiar that ancient DNA from Neolithic Europeans is dominated by Y-haplogroups I2b and G2a (missing the dominant Anatolian J2 haplogroup) and by a "Mediterranean" autosomal makeup (missing the dominant Anatolian West_Asian component). As I have previously argued, this suggests a sea change in the genetic makeup of Anatolia itself since the early Neolithic, and a Bronze Age migration of J2/West_Asian brachycephals into Anatolia, mainland Greece and Crete would be one possible agent for that development.

Late Minoan IB destructions and cultural upheaval on Crete: A bioarchaeological perspective

Nafplioti, Argyro

This paper discusses representative results from strontium isotope ratio (87Sr/86Sr) and biodistance analyses of archaeological human skeletal material carried out to assess the validity of the theory of a LMIB (ca. 1490/1470 BC) Mycenaean invasion of Crete and imposed political domination of Knossos, and thus shed more light onto the question of the LMIB destructions and the subsequent cultural upheaval on the island. These analyses show that the people buried in post- LMIB tombs at Knossos, traditionally associated with Mycenaeans based on material culture evidence, were in fact born locally and not in the Argolid. Further, the analyses presented reject the possibility that these people may represent the descendants of immigrants from the latter region. Additional negative evidence for the theory tested comes from further cranial and dental morphological analyses presented in the author’s doctoral thesis, as well as the material culture itself, briefly discussed here.

Link

Hints of East/Central Asian admixture in Northern Europe

A little more than a year ago, I noticed an interesting pattern in North Europeans: they all tended to be shifted towards East Asians in PCA plots:

With respect to the Asian- and African- shift of West Eurasian populations, I note that northern Europeans (and Basques) are less African-shifted than southern Europeans, and, at the same time they are more Asian-shifted: the 16 least Asian-shifted populations have a coastline in the Mediterranean (excluding the Portuguese), while the 16 least African-shifted populations do not (excluding the French).

The same pattern could also be observed in the arrangement of the ancestral components inferred by the Dodecad Project. The "Atlantic_Baltic" component, which is modal in Northern Europeans, exhibits lowered genetic divergences to the East Eurasian components (Siberian / East_Asian) relative to the "Southern" component which is modal (in Europe) in Southern Europeans.

The fact that Southern European populations were shifted towards the African side relative to Northern European ones across an African-Asian projection, was interpreted by Moorjani et al. (2011) as evidence of African admixture. As I noted at the time, this entailed the assumption that Northern European populations did not have East Asian admixture, which would also produce the observed pattern:

However, this is clearly a case of seeing the glass half full. The authors prefer the hypothesis that some Caucasoid groups have African ancestry, although the hypothesis that other Caucasoid groups have East Asian ancestry can equally well explain the observed pattern. Indeed, both hypotheses may explain the phenomenon they observe.

It now appears that some of the co-authors of the above paper have realised this, and have detected Central/East Asian admixture in northern Europeans. Writing in the supplement of the recent Reich et al. (2012) paper, we read this important aside:

A complication in computing this statistic is that Native American, Siberian, and East Asian  populations are not all equally genetically related to West Eurasian populations, as we can  see empirically from 4 Population Tests of the proposed tree (Yoruba, (French, (East Asian,  Native American))) failing dramatically whether the East Asian population is Han, Chukchi,  Naukan and Koryak. The explanation for this is outside the scope of this study (it has to do  with admixture events in Europe, as we explain in another paper in submission). In practice,  however, it means that we cannot simply use a European population like French to represent  West Eurasians in Equation S3.2, since if we do this, Equation S3.2 may have a non-zero  value for a Native American population, even without recent European admixture.    

To address this complication, we took advantage of the fact that east/central Asian admixture  has affected northern Europeans to a greater extent than Sardinians (in our separate  manuscript in submission, we show that this is a result of the different amounts of central/east  Asian-related gene flow into these groups). To quantify this, we computed the statistic f4(San,  West Eurasian; Pop1, Pop2) for West Eurasian = Sardinian and West Eurasian = French,  and for 24 Siberian and Native American populations (Pop1 and Pop2) (Figure S3.2). Figure  S3.2 shows a scatterplot for all 190=20?19/2 possible pairs of these populations. Within nonArctic Native populations, and within Arctic populations (East Greenland Inuit, Chukchi,  Naukan and Koryak), the statistics are close to zero, consistent with their being (approximate)  clades relative to West Eurasians. In contrast, there are deviations from zero when the comparisons are between non-Arctic Native and Arctic populations, with non-Arctic Native  populations showing consistent evidence of being genetically closer to West Eurasians.   

David Reich has hinted about ancient admixture in Europeans before, and is apparently working on the South Asian admixture event. It would appear that the new works might be using the newer techniques employed in the Reich et al (2012) paper, which allows one to consider multiple admixture events rather than the more simple ones of Reich et al. (2009) and Moorjani et al. (2011) that considered only two ancestral populations.

I will, of course, eagerly wait the publication of the mentioned manuscript, but it appears that this is not the only piece of evidence of gene flow from Central Asia into Europe. In an SMBE 2012 abstract by Palstra et al. we read:

Using an approximate Bayesian framework, we find that present patterns of genetic diversity in Central Asia may be  best explained by a demographic history which combines long-term presence of some ethnic groups (Indo-Iranians)  with a more recent admixed origin of other groups (Turco-Mongols). Interestingly, the results also provide indications  that this region might have genetically influenced Western European populations, rather than vice versa. A further  evaluation in MCMC-based Bayesian analyses of isolation-with-migration models confirms the different times of  establishment of ethnic groups, and suggests gene flow into Central Asia from the east. The results from the  approximate Bayesian and full Bayesian analyses are thus largely congruent. In conclusion, these analyses illustrate  the power of Bayesian inference on genetic data and suggest that the high genetic diversity in Central Asia reflects both  long-term presence and admixture in more recent historical times. 

Neither of these two upcoming pieces of work mention the timing of the Central Asian element in Europe: 

• One possibility is that the Mesolithic Europeans were Asian-shifted themselves. 
• Another one would relate it to the emerging ancient mtDNA picture of deep penetration of Mongoloid elements into west Eurasia at the dawn of history, although the western limit of this penetration has not been conclusively ascertained. 
• Finally, the elements may be a legacy of the Bronze Age Indo-European invasion of Europe, piggy-backing on the spread of the latter from their eastern homeland

In two of the existing models of how the latter event took place (the Armenian plateau hypothesis of Gamkrlidze and Ivanov and the Bactria Sogdiana hypothesis of Johanna Nichols), the Indo-Europeans followed separate streams from their eastern homeland into Europe, with some groups following a path north of the Black and Caspian seas, while others followed a southern path from Anatolia to the Balkans. The northern dispersal route would have brought them into contact with the mixed Caucasoid/Mongoloid population of West Siberia and Eastern Europe, and they may have carried some of this DNA across their sweep over Northern Europe.

My own working hypothesis would derive the earliest Proto-Indo-Europeans with groups living in Neolithic eastern Anatolia and northern Mesopotamia. There are details to be fleshed out, such as when this group of people reached the Balkans (pending ancient DNA from the region), and how they interfaced with the populations living in the north of the Black and Caspian seas (e.g., via a trans-Caucasus movement or a counterclockwise spread around the Caspian).

We will know soon enough how and when Northern Europeans ended up with an extra slice of Central/East Asian ancestry. Things are looking good for our understanding of events in Eurasian prehistory.