May 7, 2015

Neolithic mtDNA from the Seine basin

Finally we get some ancient DNA from the French demarcation, which should be one of the focus of the research, because of the importance of the territory of the French state in European paleo-history since the depths of the Paleolithic.

This data set is, in spite of its limitations, most important because it seems to support the notion of Megalithism being an important factor in the formation of European populations as we know them.

I strongly recommend reading the whole paper because it does not only deal with the genetic aspects but also offers excellent background on the archaeological context of the region to which these (non-monumental) burials belong to.

Maïté Rivollat et al., When the Waves of European Neolithization Met: First Paleogenetic Evidence from Early Farmers in the Southern Paris Basin. PLoS ONE 2015. Open accessLINK [doi:10.1371/journal.pone.0125521]

Abstract

An intense debate concerning the nature and mode of Neolithic transition in Europe has long received much attention. Recent publications of paleogenetic analyses focusing on ancient European farmers from Central Europe or the Iberian Peninsula have greatly contributed to this debate, providing arguments in favor of major migrations accompanying European Neolithization and highlighting noticeable genetic differentiation between farmers associated with two archaeologically defined migration routes: the Danube valley and the Mediterranean Sea. The aim of the present study was to fill a gap with the first paleogenetic data of Neolithic settlers from a region (France) where the two great currents came into both direct and indirect contact with each other. To this end, we analyzed the Gurgy 'Les Noisats' group, an Early/Middle Neolithic necropolis in the southern part of the Paris Basin. Interestingly, the archaeological record from this region highlighted a clear cultural influence from the Danubian cultural sphere but also notes exchanges with the Mediterranean cultural area. To unravel the processes implied in these cultural exchanges, we analyzed 102 individuals and obtained the largest Neolithic mitochondrial gene pool so far (39 HVS-I mitochondrial sequences and haplogroups for 55 individuals) from a single archaeological site from the Early/Middle Neolithic period. Pairwise FST values, haplogroup frequencies and shared informative haplotypes were calculated and compared with ancient and modern European and Near Eastern populations. These descriptive analyses provided patterns resulting from different evolutionary scenarios; however, the archaeological data available for the region suggest that the Gurgy group was formed through equivalent genetic contributions of farmer descendants from the Danubian and Mediterranean Neolithization waves. However, these results, that would constitute the most ancient genetic evidence of admixture between farmers from both Central and Mediterranean migration routes in the European Neolithization debate, are subject to confirmation through appropriate model-based approaches.

The studied sample comes from Gurgy (NW Burgundy, near Auxerre) and is very large: 55 successful SNP-defined haplogroups, 39 HVS-I sequences, including 27 distinct haplotypes. The burials are dated to the 6th millennium BCE, when the area was reached by Neolithic. The following haplogroups were found (table S1):

  • HV: 22, of which:
    • V - 2 (4%)
    • H - 20 (36%), of which:
      • H* - 6
      • H1 - 10
      • H3 - 4
  • U - 20, of which:
    • U* - 3 (5%)
    • U4 - 1 (2%)
    • U5 - 5 (9%)
    • K - 11 (20%)
  • JT - 8, of which:
    • J - 6 (11%)
      • J* - 4
      • J1 - 2
    • T - 2 (4%)
  • X - 2 (4%)
  • N1a - 3 (5%)


For some reason the total I get from table S1 is 51 individual haplogroups instead of the 55 expected ones. I have double and triple-checked and can't find the four missing sequences, sorry. Count corrected (May 9): there were indeed 55 sequences (my bad).

In any case the mtDNA pool is surprisingly "modern" with most haplogroups in very similar frequencies from what we would find in present day Western European populations. This is not at all like what was found in Germany's Neolithic, at least initially, characterized by low frequencies of H and high frequencies of presently rare haplogroups like N1a, being instead more similar in its "modernity" to what has been found in the Basque Country (see HERE for a quick reference).

This suggests that we have in Neolithic Europe the following regions, judging on the "modernity" of their mtDNA pools (only):
  1. Central Europe (Germany, Hungary): low H, clearly "pre-modern"
  2. Mid-Western Europe (France, Basque Country): normal H and roughly also other lineages, almost "modern"
  3. Portugal: seemingly very high H, "hyper-modern"

And this strongly hints again, along with the early presence of lactose tolerance among Chalcolithic Basques and the massive consumption of dairies among British farmers (of North French origin) to an Atlantic Neolithic origin of at least the bulk of the genetic pool of modern Western Europeans.

Sadly for the fans of patrilineal genetics, no single Y-DNA sequence could be produced.


Mostly Danubian origins?

Paradoxically these early farmers from Burgundy do not seem strongly related to the South, at least not judging by the North Iberian data used as reference but rather to the Danubian Neolithic peoples of Germany instead. This is most apparent in the haplotype graph of fig. S7:

Fig. S7 - Median-joining network


We can see that most Gurgy haplotypes (red) cluster with Danubian Neolithic ones (green) rather than with North Iberian (blue) or Paleolithic ones (purple). Basically there is only one clear exception: an H lineage that seems indeed more related to the South than to Central Europe but the red-green exclusive connections are much more common. 

However when analyzed statistically, the Gurgy population appears intermediate between the Central European and North Iberian ones. For example:


Fig 1. Principal Component Analysis (PCA) on the ancient mtDNA dataset.


Not sure if this is yet another warning about the limitations of statistical analysis or instead suggests that there is more importance of the southern ancestry but that it has a different origin in Occitania (SE France) that is not being taken into account. 

My best hunch is that the statistical result is product of the relative affinity to Basque Neolithic (the "modernity" of the overall pool as discussed above, Basque samples are by far the most numerous of Northern Iberia) combined by a more direct affinity with the German Neolithic in the detail of the sequences. 


Closer to Chalcolithic than to Early Neolithic populations

There is no haplotype structure to consider here but the statistical analysis that the authors perform does find that the Gurgy population was, oddly enough, closer to later populations in both Germany and Iberia than to their contemporaries. If this could be confirmed, we would have a candidate population for the origin of the changes that affected Europe (at least Central Europe) in the early Chalcolithic (prior to the Indoeuropean invasions). 

Fig 4. Pairwise FST distances.

It is apparent in the above figure that FST distances of the Gurgy population are much shorter (hence probably more related) with late Neolithic and Chalcolithic populations of both Central and Southwestern Europe than with any population that pre-dated the abandonment of the necropolis. Among these however it is Karsdorf the one most closely related, reinforcing the notion of a mainly Danubian origin, albeit a bit peculiar one (Derenburg, Halberstadt and the average "PRE_Central_F" are not particularly close).

But the most interesting part is surely the much greater affinity to the populations after the 4000 BCE chronological divide, which is also the baseline of the expansion of the Megalithic phenomenon. This matter requires more detailed analysis but it does suggest that the Franco-Basque area could well have been important in the formation of Chalcolithic and therefore modern European populations in the Western half of the subcontinent. A vehicle for this demographic "reform" should have been Megalithism, no doubt.

But we do need more data, sure we do.

April 3, 2015

19 Ka BP old mtDNA H from Cantabria

Jean Lohizun points me to this new study by the EHU-UPV paleogeneticist team, which reviews the ancient DNA evidence from the Cantabrian strip (or "fringe" as they call it) and, most importantly announces the oldest confirmed mtDNA H to date: belonging to an individual from El Mirón cave (Ramales, Cantabria, bordering the Basque Country), which is assigned to earliest Magdalenian culture and dated to 19,000 BP.

Update (Apr 24): the genetic findings of El Mirón were first published (in Spanish) in: M. Hervella et al., El ADN mitocondrial de los cazadores-recolectores de la región cantábrica: nueva evidencia de la cueva de El Mirón, Revista Española de Antropología Física - Vol. 35 (2014). I could not find an online reference but I have a copy of the article thanks again to Jean.

Concepción de la Rúa et al., Ancient DNA in the Cantabrian fringe populations: A mtDNA study from Prehistory to Late Antiquity. Quaternary International, 2015. Pay per viewLINK [doi:10.1016/j.quaint.2015.01.035]

Abstract

The present mtDNA study on human remains of fourteen archaeological sites from Cantabria, Basque Country and Navarra provided a diachronic overview from Paleolithic–Mesolithic to Late Antiquity period of some communities settled in the Cantabrian fringe. Ancient DNA studies in European human remains indicated a genetic discontinuity between the hunter–gatherers and later populations. However, some of the mtDNA lineages found in the Cantabrian fringe in Paleolithic–Mesolithic times persist in present-day populations.

The mtDNA variability observed in hunter–gatherers and farmers in Europe denoted a complex pattern for the Neolithic transition, occurring along several different routes into and across Europe. The mtDNA lineages found in the Cantabrian fringe indicated that the dispersion of Neolithic farmers had a different genetic impact in this area with respect to Central and Mediterranean regions of Europe. The differences in mtDNA variability were also apparent after the Neolithic, as shown by the genetic distance between the Chalcolithic populations from the Cantabrian fringe and the Bell Beaker Culture (BBC) populations of Central Europe. 

It must be mentioned that they seem to have forgotten the thesis of Marie Lacan[fr], which reported mtDNA H in Linatzeta cave (Basque Country, Epipaleolithic) and Franchthi cave (Greece, Meso-Neolithic transition), among other more recent aDNA sequences. See here for my English language synthesis.

Otherwise they list all the sequences considered in their paper in table 1:

Annotations by Maju: red: El Mirón (new sequence), orange: other Paleolithic or Epipaleolithic sequences

After including Linatzeta (Lacan 2011), we get the following frequencies in the Eastern Cantabrian sub-region (Basque Country + Cantabria) for pre-Neolithic times:
  • H: 4/6=2/3=67%
    • H-CRS (H1 surely): 33%
    • H6: 16%
    • H*: 16%
  • U5: 2/6=1/3=33%
    • U5*: 16%
    • U5b1: 16%
Notice anyhow that if we choose to draw a line between Cantabria and the Basque Country, then we get a sharp contrast: 
  • Cantabria: 100% H
  • Basque Country: 67% U5 + 33% H* (or even an illusory 100% U5 if we use only the table above, ignoring Lacan's data)
Does this apparent sharp contrast make any sense? Well, one possible interpretation comes from carefully taking into account the data we have on Iberian Solutrean and Magdalenian, which indicates that:
  1. South Iberian (from Valencia to Portugal) Solutrean is heavily influenced by the Gravettian substrate (otherwise "pure Solutrean" is restricted to two caves), configuring a unique facies sometimes called Gravetto-Solutrean.
  2. South Iberian Gravetto-Solutrean, probably in its way to Portugal, strongly affected the Upper Paleolithic of Northwest Africa, being a decisive force in the Iberomaurusian or Oranian genesis. Backflows can't be discarded because of the innovation of tanged and winged arrow points, which may have been inspired by North African Aterian technology.
  3. The Portuguese branch of this Gravetto-Solutrean was the actual source (via Salamanca) of Asturian Solutrean, unlike what happened in Cantabria and the Basque Country, directly influenced by Aquitaine. 
  4. In the subsequent Magdalenian there might have been an expansion eastward of the Asturian population, because the facies divide moves to the east (so we have a Cantabro-Astur facies and a Basque facies).
In addition to that, it may be worth considering the issue of North African genetic influence in the Western Third of the Iberian Peninsula, which incidentally and irregularly includes Cantabria but not the Basque Country. Also Chandler et al. 2005 reported high frequencies of mtDNA H (and low of U) in Epipaleolithic Portugal.

I guess that other interpretations are possible such a more subtle cline or patchy distribution but I would not discard this hypothesis, which in essence proposes that Solutrean and Magdalenian were in general dominated by U5 but this did not affect (at least not very intensely) most of Iberia, nor surely other regions like Italy or Eastern Europe, where we see haplogroups that are not U5 (Sunghir's and Karelian H, Italian mysterious HV, etc.)

This implies that the main redistribution of mtDNA H in Europe, that part organized around H1 (which also includes H3 and various H*) actually happened mostly in the Neolithic from areas like Portugal. However we know nearly nothing about the Atlantic pre-Neolithic DNA North of the Bidasoa River (some of which could also be H, particularly R*-CRS reported in Britain) so multiple sources are possible. The huge blank of data corresponding to the Western French State and also Atlantic Islands, etc. is crying for a comprehensive sampling, and not just for mtDNA. 


Neolithic Basque mtDNA is unlike what is found in Continental Europe

The authors pay limited attention to the issues relative to Paleolithic and dedicate most of the paper to analyze the Basque ancient mtDNA in contrast to other comparable data from elsewhere in Europe. This is synthesized in fig. 2:

Fig. 2. Multidimensional Scaling analysis (MDS), based on a Fst genetic matrix calculated from the frequency distribution of the mtDNA haplogroups of different populations [Neolithics (green), Chalcolithics (purple), Late Antiquity (red), present-day Near East and northern Caucasus (orange) and Europeans (black)]. Abbreviations for present-day populations in Europe: Eastern Mediterranean (MdE), Central Mediterranean (MdC), Western Mediterranean (MdW), Northeast Europe (NE), NortheCentral Europe (NC), Northwest Europe (NW), Southeast Europe (SE) and Alps (ALP). (For interpretation of the references to colour in this figure legend, the reader is referred to the web version of this article.).


Notice that all the ancient mtDNA from the so-called "Cantabrian Fringe" in this graph is from the Basque Country (Navarre included), often outside of the Cantabrian strip and rather from the Upper Ebro basin. Notice also that the all the Chalcolithic data belongs to military contexts from the Ebro Valley and are probably therefore not representative of the overall Basque region, although they may represent well the Upper Ebro in that period (more influenced apparently by Mediterranean inputs of Cardial affinity).

Also I already discussed all this (and more) quite in depth in my dedicated entry of 2013

The authors argue that Germany's Bell Beaker samples (BBC) are not quite similar to the Basque ancient and modern pools, what is true if you are nit-picky enough, but they share the same common tendency in PC1 towards modernity. In contrast all other Neolithic samples are clearly non-modern European and must have been largely suffered by replacement in the Chalcolithic or later periods.


PS- I forgot to mention that apparently Paabo and co. had already sequenced this very same specimen in 2013, yet they have not published anything for unknown reasons, some think that ideological ones. It's of course possible that they do have good reasons but two years is a long time to await publication really, we the people, who pay their salaries and budget with our extreme economic pains, expect reliability from our well-paid researchers.

March 11, 2015

Everything you wanted to know about Balcan and Carpathian Neolithic

Prolific researcher Esther Bamfy recently uploaded to her academia.edu page this most interesting publication, which, even if it is not "recent", has a load of information on the Neolithic of the Balcans, which is crucial to understand that of Europe in general.

Various authors. A SHORT WALK THROUGH THE BALKANS:THE FIRST FARMERS OF THE CARPATHIAN BASIN AND ADJACENT REGIONS. Proceedings of the Conference held at the Institute of Archaeology UCL on June 20th - 22nd, 2005. Freely available at academia.edu → LINK.

The collection is pretty much exhaustive but the paper that most caught my attention was the one by J.K. Koszlowski, titled "Western Anatolia, the Aegean Basin and the Balcans in the Neolithisation of Europe", which underlines that, contrary to pop culture ideas, often making headway into flawed genetic or linguistic studies, the first European Neolithic of Greece (Thessaly and Argolid) can't be related to Western Anatolia, where there was no such Neolithic yet but probably arrived, maybe via Cyprus, by sea.

This is coincident with what I wrote months ago at PPNB ancient mtDNA and its legacy.

But all 18 papers are very much worth reading anyhow, take a look. 

SW Iberia shattered by tsunamis every 700 years

The Lisbon earthquake of 1755 is only the latest example of a long chain of destructive tsunamis affecting SW Iberia and NW Africa, which seem now to be recurrent with a approximate regularity of ~700 years for 8 Mw events and ~3500 years for larger 8.7 Mw ones. Those are the conclusions of a geological study in the coast of Cádiz Province (Andalusia) focused on describing one that left a clear mark in the coastal sediment some 4200 years ago.

Benjamin Koster & Klaus Reicherter. Sedimentological and geophysical properties of a ca. 4000 year old tsunami deposit in southern Spain. Sedimentology 2015. Pay per view → LINK [doi:10.1016/j.sedgeo.2014.09.006]

Paper freely available at Researchgate anyhow.

Abstract

The coastlines around the Gulf of Cádiz were affected by numerous tsunami events damaging infrastructure and causing countless human losses. A tsunami deposit at Barbate–Zahara de los Atunes, Spain, is located at various heights above mean sea level and shows several characteristics indicative of high-energy event deposition. This study uses sedimentology, foraminifera assemblage, magnetic susceptibility, X-ray fluorescence analysis, ground penetrating radar (GPR) to support an interpretation of high-energy deposition and determine the deposit's transport mechanisms and sediment source. Radiocarbon and optically stimulated luminescence dating of the tsunami deposit reveals ages of ~ 4000 BP and does not support the AD 1755 Lisbon event as suggested in former publications.

I fin this particularly interesting because the city that was for some 1500 years the main one of Atlantic Europe, central in both Megalithism and Bell Beaker, the so-called Castro do Zambujal (Torres Vedras, Portugal), was abandoned c. 1100 BCE after the canal of 10 km. that linked it to the ocean was silted, maybe by one of these devastating tsunamis.

This event, as well as many other details (length of the canal, geographical location beyond The Pillars, Mycenean Greek influence in presumably rival El Argar civilization, number of princely tombs, extension of Megalithism to "Lybia and Tyrsenia"...) fit strangely too well with the narration of Plato about Atlantis, which would then have happened just some 900 years (and not 9000) before his life. With less detail, the Mycenaean presence in Iberia would also correspond well with two of the mythical works of Herakles (Hercules): the conflict with Geryones and the stealing of the Hesperian apples by cheating Atlas. The early Greeks, whose influence in El Argar B is very apparent in the adoption of pithos (jar) burial, would have gone there largely in search of tin, the strategical mineral of the Bronze Age, which was only found in abundance in NW Iberia (and Cornwall but that source was exploited only later, it seems). 

February 13, 2015

Kurgan ancient DNA suggests major impact in North-Central Europe

After many rumors and pointless discussions based on them, finally the Haak et al. study on ancient Kurgan DNA is available only (pre-pub format):

W. Haak et al., Massive migration from the steppe is a source for Indo-European languages in Europe. bioRxiv 2015 (freely available pre-pub) → LINK [doi: http://dx.doi.org/10.1101/013433]

The study expands on previous work by Lazaridis 2014 by including a much larger array of ancient DNA from Germany and Hungary, as well as some key ancient DNA from Russia and also some complementary samples from Northern Iberia.


Autosomal DNA

Even if the authors admit it is difficult to properly quantify, there are clear tendencies that are outlined in fig. 2:

Figure 2: Population transformations in Europe. (a) PCA analysis, (b) ADMIXTURE
analysis. The full ADMIXTURE analysis including present-day humans is shown in
Extended Data Fig. 1.
Annotations in red by me.

The main inferred processes of demographic formation of the modern European genetic pool are outlined:
  1. A baseline of Epipaleolithic hunter-gatherers that pulls in the PC 1 towards the left (geographically would be the Atlantic). I call this layer Paleo-European (PE).
  2. A first replacement by Neolithic farmers of Thessalian origin (already discussed in depth in Lazaridis 2014), who were similar to modern Sardinians. I call this layer Neo-European (NE).
  3. A reflux of Paleo-European genetics that alters the Neo-European layer somewhat. This can be associated to Atlantic Neolithic flows (i.e. Megalithism, Funnelbeaker, etc.) We can call this stage Neo-European-2 (NE2).
  4. A second replacement wave by Steppe tribals, certainly bringing the Indoeuropean languages (IE).

Modern European populations align well along a IE-NE2 axis, whose midpoint seems to fall on North France, depending of course on which references you choose. I drew that axis as dotted red line. It is not substantively different from the Dimension 2 axis, although it is slightly slanted because the IE invaders obviously carried more PE than the NE layer. This new PE is not WHG (Magdalenian) but EHG (Eastern Epi-Gravettian) however - and hence its tendency towards Paleo-Siberian genetics (Ma1 or "ANE").

So Dimension 1 quite apparently contrasts the Paleo-European vs the West Asian components. What does Dimension 2 express? A quite apparent element is the Paleo-Siberian tendency. Alternatively it can also be considered to express the distinction between Lowland and Highland West Asians. Finally it can also be expressed as IE vs NE. All three are surely just variants of the same continental vs peripheral opposition, which is weaker than the PE vs West Asia one.

I must mention that fig. S5.2 offers a slightly different view:

Figure S5.2: PCA analysis with ancient individuals projected onto the variation of the
present-day ones.

Notable is that the NE-IE axis (not drawn) appears more slanted, with most modern populations showing greater excess of PE tendency and less "obviously" resolved by the late Chalcolithic populations (LNE/EBA in the authors terminology). 

As I said above, it seems very difficult to objectively measure the exact fractions of admixture (the tendencies are clear but the quantification not so much) and something that is becoming more and more painfully obvious is that Atlantic European ancient genomes are needed to explain the changes that happened prior to the arrival of Kurgans. Particularly it'd be most interesting to get ancient samples from: Portugal (Neolithic, Megalithic and Bronze Age), Basque Country and Gascony (Neolithic and Megalithic at the very least, preferably from the coastal regions), Brittany and West France (Neolithic, Megalithic 1 and Artenacian), Belgium (non-LBK Neolithic), Britain (several regions preferably, as the British Neolithic seems to have strong regional differences), West Germany (Michelsberg culture). This array or at least a sensible part of it could shed light on key processes taking place before and after the Kurgan migration. Bell Beaker samples from outside Central Europe would also be very interesting. 

I would also be interesting to see a PCA without West Asians, whose presence quite apparently does not add much to the analysis. It is known that when the PCA is European-only (or mostly), Basques and Sardinians display clearly different polarities (typically Sardinians vs Russians in PC1 and Basques vs Caucasians in PC2). It would be very interesting to observe how these ancient samples behave in a Europe-only PCA.


Y-DNA

A lot of the upheaval was around the fact of the finding of some R1b in Samara Valley. This is very interesting indeed but it is not the kind R1b that can be considered ancestral to modern European mainline R1b-M412. It is mostly of a different haplogroup whose modern distribution is unknown to me: R1b-Z2103.

*Update: some people have commented that R1b-Z2103 is found in West Asia and some Volga peoples.

Schematically (following YSOGG), R1b-M343 and its sole relevant subclade R1b1-M415 are structured as follows:
  • R1b1a (L320)
    • R1b1a2a1 (L51/M412)
      • R1b1a2a1a (P311) 
        • R1b1a2a1a1 (U106) → NW Europe
        • R1b1a2a1a2 (P312/S116) → SW Europe with scatter elsewhere in the continent, including Ireland, Britain, Italy... Found in Kromsdorf (late Chalcolithic)
    • R1b1a2a2 (CTS1078/Z2103) → found in Samara culture
  • R1b1b (M335) → minor, West Asia
  • R1b1c (V88) → Mediterranean and Africa, particularly important in Sardinia and Central-East Africa.
Note: for further information on European R1b see HERE and HERE.
Otherwise all the spotted R1b in this study is R1b1*: in Samara culture and in Neolithic Aragon (NE Iberia), both of which are hard to relate to anything of modern relevance.  

Corded Ware is associated to R1a only at this time. So at least in Europe it makes good sense to associate Kurgan expansion with R1a expansion. 


Mitochondrial DNA

There is plenty of mtDNA data but most is recycled from previous studies so not really novel. An interesting detail is that there is no or nearly no mtDNA H within the Kurgan (IE) samples, strongly suggesting that their migration was largely male-biased, at least initially. As happens with Y-DNA R1b, Kurgan immigrants cannot be associated to any increase of mtDNA H, whose origins must therefore be sought in some other origin (namely: Atlantic Neolithic).


Note: my apologies for being so extremely passive in my blogging activity. I don't really know how to explain other than feeling OLD AND TIRED and needing LOTS of "me time". It's time for others to pick up the torch, I guess.

August 13, 2014

Chalcolithic mtDNA from Atapuerca still in the Neolithic range

Bell Beaker Blogger points me to this latest study on ancient mtDNA from the Center-North Iberian Peninsula, including 20 samples from a Chalcolithic site (without Bell Beaker apparently) that clearly shows continuity with mainline Neolithic (Cardium but also similar to Central European Linear Pottery Culture, both sharing the same Thessalian ultimate origins).

Daniel Gómez Sánchez, Iñigo Olalde et al., Mitochondrial DNA from El Mirador Cave (Atapuerca, Spain) Reveals the Heterogeneity of Chalcolithic Populations. PLoS ONE 2014. Open accessLINK [doi:10.1371/journal.pone.0105105]

Abstract

Previous mitochondrial DNA analyses on ancient European remains have suggested that the current distribution of haplogroup H was modeled by the expansion of the Bell Beaker culture (ca 4,500–4,050 years BP) out of Iberia during the Chalcolithic period. However, little is known on the genetic composition of contemporaneous Iberian populations that do not carry the archaeological tool kit defining this culture. Here we have retrieved mitochondrial DNA (mtDNA) sequences from 19 individuals from a Chalcolithic sample from El Mirador cave in Spain, dated to 4,760–4,200 years BP and we have analyzed the haplogroup composition in the context of modern and ancient populations. Regarding extant African, Asian and European populations, El Mirador shows affinities with Near Eastern groups. In different analyses with other ancient samples, El Mirador clusters with Middle and Late Neolithic populations from Germany, belonging to the Rössen, the Salzmünde and the Baalberge archaeological cultures but not with contemporaneous Bell Beakers. Our analyses support the existence of a common genetic signal between Western and Central Europe during the Middle and Late Neolithic and points to a heterogeneous genetic landscape among Chalcolithic groups.

The results show intense similitude with Catalan Neolithic and Languedoc's Chalcolithic but also with Central European Neolithic. They contrast instead with Portuguese and Basque Neolithic, as well as with Central European Bell Beaker, all them much higher in haplogroup H and, in the Basque case, also in U (being the most modern-like of all ancient mtDNA pools known before the Bronze Age in Europe).

Annotated version of fig. 2
Figure 2. Mitochondrial DNA haplogroup frequency for 21 ancient European samples.
This study: El Mirador (MIR). Published prehistoric cultures [21]: Hunter-gatherer central (HGC), Linear Pottery culture (LBK), Rössen culture (RSC), Schöningen group (SCG), Baalberge culture (BAC), Salzmünde culture (SMC), Bernburg culture (BEC), Corded Ware culture (CWC), Bell Beaker culture (BBC), Unetice culture (UC), Funnel Beaker culture (FBC), Pitted Ware culture (PWC), Hunter-Gatherer south (HGS), (Epi) Cardial (CAR), Neolithic Portugal (NPO), Neolithic Basque Country and Navarre (NBQ), Treilles culture (TRE), Hunter-gatherer east (HGE), Bronze Age Siberia (BAS), Bronze Age Kazakhstan (BAK).

Notice please that the above column for Central European Bell Beaker (BBC) includes the more than dubiously attributed Kromsdorft site, which has a totally different genetic signature. In my previous analysis of European ancient DNA evolution, I treated them separately and I still think that it is much more correct to do it that way.

Notice also that one sample from Mirador was sequenced for autosomal DNA by Evangelia Dasakali, producing an Italian-like sequence, roughly in line with other early European farmers, excepted the Atlantic ones. See here.

So what we see is a "wedge" of Mediterranean or Neolithic ancestry probably penetrating along the Ebro river up to Atapuerca and contrasting with Atlantic Iberian (Basque and Portuguese) ancestry, more modern-like or even "hyper-modern" (by contrast with mainline farmers) in the case of Portugal. This same contrast exists with Central European Bell Beaker sites and also (in the autosomal DNA aspect) with Megalithic farmers from Southern Sweden. 

None of those "modernizing" tendencies can be found instead among Eastern European Neolithic peoples nor among early Indoeuropeans of Central Europe such as those of the Unetice culture. So the overall conclusion can only be that there was in the Chalcolithic (and to some extent Neolithic) a duality of ancestries between the Mainline or Mediterranean (but also Danubian) Neolithic and a more "modern" Atlantic Neolithic, which is related to the Megalithic and Bell Beaker cultural phenomena (and in North-Central Europe also to Funnelbeaker). 

There are still a lot of dark spots in our understanding of how this "modernization" or "Westernization" of the genetic pool happened but, in general terms, it seems to imply a sizable (albeit somewhat irregular) demographic flow from Atlantic Europe into the areas previously occupied by Mainline Neolithic populations of partial West Asian affinity. This is apparent in both mtDNA as in autosomal DNA. 

These sequences from El Mirador (Atapuerca) only underline this phenomenon and the fact that in the Chalcolithic, some 4500 years ago, this process of "modernization" of the European genetic pool was still incomplete.

July 30, 2014

Bell Beaker of Estremadura (Portugal)

This is a very interesting read for everyone interested in the Chalcolithic Era and particularly in the Bell Beaker phenomenon in one of its most crucial areas: the Lisbon Peninsula of Portugal:

João Luís Cardoso. Absolute chronology of the Beaker phenomenon North of the Tagus estuary: demographic and social implications. Trabajos de Prehistoria 2014. Open accessLINK [doi: 10.3989/tp.2014.12124]

Abstract

The complexity of the Beaker phenomenon in the Tagus estuary does not fit well with the model of three successive groups (International, Palmela and Incised Groups). The above seems to result from the nature of the settlements rather than from its chronology, as all three groups are present during the second half of the 3rd millennium BC. Therefore while artefacts of the International Group predominate in the fortified sites, the Incised Group appears almost exclusively in open sites. The Palmela Group seems of minor importance, at least in the north region of the Tagus River estuary. The remarkable antiquity of Beaker pottery found in the FM hut at Leceia (which dates from the 2nd quarter of the 3rd millennium BC, re-confirmed by AMS dating) has parallels both in the North and South of Portugal, as well as in Spain. Thus we conclude that in the Lower Estremadura (one of the most important regions in Europe for the discussion of the origin and diffusion of Beaker “phenomenon”), the Beaker social formation with its own distinct cultural characteristics, coexisted with local Chalcolithic cultures, although never merged with them.


Fig. 2. Leceia. Plan of the fortified settlement, with the
location of the two Bell Beaker huts identified outside the walls.
One of the important findings of this study is that the Incised Bell Beaker style is strictly contemporary of the International style and not a later development. The difference is that, while the International (or Maritime) high quality pottery style dominated the fortified settlements, their rural hinterland used the more modest Incised style pottery or, in some cases, no Bell Beaker pottery at all. 

The author questions the traditional tripartite division between Early, Full and Late Chalcolithic (with Bell Beaker only present in the late stage) and claims a simpler division between Early and Full/Late Chalcolithic based not only on Bell Beaker presence but also of the more widespread local pottery styles (channeled and acacia-leaf decoration). 

He also argues that, somehow, there was a "cultural" (or is it "class"?) division between the fortified cities and their rural hinterland, division that would reappear later in the Bronze Age. This division is largely defined by certain pottery styles and particularly quality. A possible interpretation I do is that this reflects a division between a cosmopolitan urban "elite" and a rural society that was not immersed in this cosmopolitanism of the fortified towns. The author finds no sign of conflict between the two areas.
On a more global approximation to the socio-cultural reality during the 2nd half of the 3rd millennium BC in Lower Estremadura, we may consider that if Beaker society was segmented with two clearly differentiated components, it may have corresponded nevertheless to a cultural entity as a whole with its own characteristics, at least in the region under appreciation.

The absolute chronology for the earliest bell beakers in Estremadura is 2700-2600 BCE, prior to the transition between the two Chalcolithic phases (c. 2600-2700 BCE in Leceia).

I find the following particularly interesting:
The comparison of chronometric and archaeological results described above suggests that the first Beaker productions in the region of Lower Estremadura (between about 2700 and 2600 BC) coexisted, with lower interaction, with Chalcolithic populations that lived in some fortified sites, as shown by the chronology of the FM hut at Leceia. This is the same period in which fluted pottery typical of the Early Chalcolithic of Estremadura was still used inside this fortified settlement. But in other cases this coexistence was followed by interaction with the inhabitants of those already-existing fortified sites (as found in the fortified Chalcolithic settlement of Zambujal).

This interaction persisted throughout the whole Full Chalcolithic (represented by the characteristic “acacia-leaf” ceramic pattern) until the end of the 3rd millennium BC, as can be seen in almost all the fortified settlements of Lower Estremadura.

Does this support the formation of Bell Beaker as some sort of "sect" or distinctive "ethnic group", which only in a second phase became inserted in the wider local society? One possible interpretation might be that Bell Beaker users could have arrived from elsewhere as some sort of colonists, maybe a colony of specialist traders or metallurgists or even a religious community, but, if so, where from?, because Iberia seems to have the oldest Bell Beaker dates?

Estremadura is today one of the most likely candidates for the formation of the Bell Beaker phenomenon but this paper also mentions similarly older dates in other parts of Portugal, and the same seems true for other parts of Iberia and SE France. Whatever its exact origin, it seems likely that the vibrant and often ill-understood Chalcolithic civilization of Estremadura was surely a trampoline from which the important cultural phenomenon reached other areas of Atlantic (and maybe even inland) Europe.