On the Maykop – Upper Mesopotamia cultural province, distinct from the steppe

caucasus-europe

New paper (behind paywall) The Production of Thin‐Walled Jointless Gold Beads from the Maykop Culture Megalithic Tomb of the Early Bronze Age at Tsarskaya in the North Caucasus: Results of Analytical and Experimental Research, by Trifonov et al. Archaeometry (2018)

Interesting excerpts (emphasis mine):

In 1898, two megalithic tombs containing graves of a local social elite dated to the Early Bronze Age were discovered by N. I. Veselovsky near the village of Tsarskaya (modern Novosvobodnaya, Republic of Adygeya) (Fig. 1 (a)) (Baye 1900, 43–59; IAC 1901, 33–8; Sagona 2018, 281–97).

Radiocarbon dates place both tombs within the Novosvobodnaya phase of the Maykop culture, between c. 3200 and 2900 BC (Trifonov et al. 2017). Along with the human remains (one adult individual was interred in each dolmen), the tombs yielded rich funerary offerings, including artefacts made of gold, silver and semi-precious stones. (…) This paper presents results of a technical analysis of just one type of artefact, from kurgan 2 at Tsarskaya: thin-walled jointless beads made from gold.

caucasus-beads-mesopotamia-sumeria
(a) A map of the Caucasus and part of Western Asia, showing the locations of sites mentioned in the text: 1, Tsarskaya (modern Novosvobodnaya); 2, Maykop; 3, Staromyshastovskaya; 4, Andryukovskaya; 5, Psebaiskaya; 6, Inozemtsevo; 7, Kudakhurt; 8, Soyuq Bulaq; 9, Sé Girdan; 10, Tepe Gawra. (b) The string of thin-walled jointless gold beads, silver and carnelian beads from the dolmen in kurgan 2 at Tsarskaya, Western Caucasus (1898).

Ever since M. I. Rostovtzeff noted a stylistic similarity between Maykop art and Sumerian art (Rostovtzeff 1920) and M. V. Andreeva described this phenomenon within a broad cultural and chronological context (Andreeva 1977), new archaeological studies have only extended this picture of a vast cultural province that appeared between the Caucasus and the northern fringe of Western Asia (Trifonov 1987). The discovery of the Leyla-Tepe culture (Narimanov 1987) and Maykop-type kurgans in Azerbaijan (Lyonnet et al. 2008) and adjacent Iran (Muscarella 1969, 1971, 2003; Trifonov 2000) has confirmed the spatial and temporal unity of this phenomenon as a precondition for free circulation of cultural patterns and technical innovations across vast areas of the Caucasus and Western Asia. Jewellery made of gemstones and precious metals, primarily gold, was probably one such innovation.

Attempts to demarcate the historical region where the Maykop culture emerged and developed have emphasized the role of Upper Mesopotamia in the development of the Sumerian civilization and the definition of a northern centre of urbanization, independent from the centres of the south (Rothman 2002; Oats et al. 2007). The turn of the fourth millennium BC saw the development of various cultural traditions in south-east Anatolia, north-east Syria and north-west Iran; on the northern fringe, these traditions manifested themselves through the Maykop culture. Perhaps it is no coincidence that the first high-status burials containing gold and gemstone jewellery (including carnelian, turquoise and lapis lazuli) appear in these northern, rather than southern, centres in the first quarter of 4000 BC (e.g., Tepe Gawra, graves 109, 110) (Piasnall 2002). With regard to funeral rites and stylistic characteristics of jewellery pieces, these graves have many parallels with early Maykop burials (Munchaev 1975, 329; Trifonov 1987, 20).

It still remains unclear if the goldsmiths of Upper Mesopotamia mastered the technique of making thin-walled jointless beads. The gold beads from Tepe Gawra are described as spherical or ball-shaped, but their maximum diameter (5–8mm) always exceeds the length of the bore (3–4mm) (Tobler 1950, 89, 199, pl. LV, a). On the whole, these measurements are consistent with the proportions and sizes of some Maykop beads.(…)

It is quite possible that a distinctive technique of making thin-walled jointless beads from gold was a regional technological development of Maykop culture goldsmiths, within a wider tradition of Near East metalwork, as a type of production regulated by ritual beliefs (Gell 1992; Benzel 2013).

These deep-rooted Near East traditions of ritualization of the production and use of jewellery pieces made of gold, silver and gemstones in the Maykop culture, on the one hand, maintained familiar canons of ritual behaviour and, on the other, made perception of sophisticated symbolism of gemstones more difficult for neighbouring cultures with different living standards, levels of social development and value systems to understand. The jewellery traditions of the Maykop culture had no successors in the Caucasus or the adjacent steppes. In the third millennium BC, the goldsmiths of Europe and Asia had to reinvent the technique of making thin-walled jointless gold beads from scratch (Born et al. 2009).


Also interesting is Holocene environmental history and populating of mountainous Dagestan (Eastern Caucasus, Russia), by Ryabogina et al., Quaternary International (2018).

caucasus-dagestan-climate-population
The combination of Holocene environment changes and the settlement of the territory of Dagestan.

Related excerpts, about the climate of an adjacent region of the Caucasus before, during, and after the Maykop culture:

The 7th millennium BC featured a warm and arid climate, so that time corresponds to the steppe landscapes in the final stage of the Mesolithic. It is likely that the formation of a producing economy in the mountainous zone of Dagestan gradually emerged against this background. In the Neolithic period, the area remained almost treeless, as it was still warm and quite dry. However, archaeological data indicates that long-term settlements with well-developed farming spread in the mountainous zone around 6200-5500 BC.

The beginning of increasing humidity and the appearance of deciduous forests corresponds to the early Chalcolithic period of the Eastern Caucasus. It is the most poorly studied period in the history of this region. Covering a time span of 2000 years, this period was the least saturated by archaeological sites. At the start of this period, only the stands of herdsman in the mountain zone are known, dating to the second half of the 6th millennium BC (Gadgiev, 1991). It is still not clear whether the mountains were not settled in such a favorable climatic stage. The uncertainty may be due to the fact that people have chosen other ecological niches, or it could be we simply do not have data due to the insufficient archaeological survey of the territory. It is surprising that the turn to drier climate and the reduction of deciduous forests in the inner mountainous part of Dagestan, the large, long-term settlements like Ginchi emerge with pronounced specialization in agriculture (Fig. 7 panel (2)) (Gadgiev, 1991).

After the dry climate, simultaneously with cooling, the subsequent spread of pine forests coincides with the beginning of expansion of Kura-Araxes culture from the territory of Georgia through Chechnya to the mountainous Dagestan. Debates on the impact of past climate on Kura-Araxes societies in Transcaucasus have a long history (for the comprehensive review see, for example, Connor and Kvavadze, 2014 and references therein). In general, it is clear that after 3000 BC, forest cover in most areas of the Kura-Araxes region in the Transcaucasia reached its maximum extent in the Holocene (Connor and Kvavadze, 2014). However, at the same time lakes in Central Anatolia began to dry out and Caspian Sea levels fell (Roberts et al. 2011; Leroy et al. 2013), and arid conditions were identified in mountainous Dagestan in the 4th millennium. Clearly the regional moisture balance shifted in the Eastern Caucasus only in the late 4th to early 3rd millennium BC (this study). The only available radiocarbon dating of Dagestan confirms that the agricultural settlements of the Early Bronze Age appear not in the middle of the 4th millennium BC, but in the early 3rd millennium BC; that is not earlier than the stage of increasing moistening and the appearance of pine forests.

See also:

Ancient genomes from North Africa evidence Neolithic migrations to the Maghreb

BioRxiv preprint now published (behind paywall) Ancient genomes from North Africa evidence prehistoric migrations to the Maghreb from both the Levant and Europe, by Fregel et al., PNAS (2018).

NOTE. I think one of the important changes in this version compared to the preprint is the addition of the recent Iberomaurusian samples.

Abstract (emphasis mine):

The extent to which prehistoric migrations of farmers influenced the genetic pool of western North Africans remains unclear. Archaeological evidence suggests that the Neolithization process may have happened through the adoption of innovations by local Epipaleolithic communities or by demic diffusion from the Eastern Mediterranean shores or Iberia. Here, we present an analysis of individuals’ genome sequences from Early and Late Neolithic sites in Morocco and from Early Neolithic individuals from southern Iberia. We show that Early Neolithic Moroccans (∼5,000 BCE) are similar to Later Stone Age individuals from the same region and possess an endemic element retained in present-day Maghrebi populations, confirming a long-term genetic continuity in the region. This scenario is consistent with Early Neolithic traditions in North Africa deriving from Epipaleolithic communities that adopted certain agricultural techniques from neighboring populations. Among Eurasian ancient populations, Early Neolithic Moroccans are distantly related to Levantine Natufian hunter-gatherers (∼9,000 BCE) and Pre-Pottery Neolithic farmers (∼6,500 BCE). Late Neolithic (∼3,000 BCE) Moroccans, in contrast, share an Iberian component, supporting theories of trans-Gibraltar gene flow and indicating that Neolithization of North Africa involved both the movement of ideas and people. Lastly, the southern Iberian Early Neolithic samples share the same genetic composition as the Cardial Mediterranean Neolithic culture that reached Iberia ∼5,500 BCE. The cultural and genetic similarities between Iberian and North African Neolithic traditions further reinforce the model of an Iberian migration into the Maghreb.

north-africa-genomes-pca
Ancestry inference in ancient samples from North Africa and the Iberian Peninsula. PCA analysis using the Human Origins panel (European, Middle Eastern, and North African populations) and LASER projection of aDNA samples.

Relevant excerpts:

FST and outgroup-f3 distances indicate a high similarity between IAM and Taforalt. As observed for IAM, most Taforalt sample ancestry derives from Epipaleolithic populations from the Levant. However, van de Loosdrecht et al. (17) also reported that one third of Taforalt ancestry was of sub-Saharan African origin. To confirm whether IAM individuals show a sub-Saharan African component, we calculated f4(chimpanzee, African population; Natufian, IAM) in such a way that a positive result for f4 would indicate that IAM is composed both of Levantine and African ancestries. Consistent with the results observed for Taforalt, f4 values are significantly positive for West African populations, with the highest value observed for Gambian and Mandenka (Fig. 3 and SI Appendix, Supplementary Note 10). Together, these results indicate the presence of the same ancestral components in ∼15,000-y old and ∼7,000-y-old populations from Morocco, strongly suggesting a temporal continuity between Later Stone Age and Early Neolithic populations in the Maghreb. However, it is important to take into account that the number of ancient genomes available for comparison is still low and future sampling can provide further refinement in the evolutionary history of North Africa.

Genetic analyses have revealed that the population history of modern North Africans is quite complex (11). Based on our aDNA analysis, we identify an Early Neolithic Moroccan component that is (i) restricted to North Africa in present-day populations (11); (ii) the sole ancestry in IAM samples; and (iii) similar to the one observed in Later Stone Age samples from Morocco (17). We conclude that this component, distantly related to that of Epipaleolithic communities from the Levant, represents the autochthonous Maghrebi ancestry associated with Berber populations. Our data suggests that human populations were isolated in the Maghreb since Upper Paleolithic times. Our hypothesis is in agreement with archaeological research pointing to the first stage of the Neolithic expansion in Morocco as the result of a local population that adopted some technological innovations, such as pottery production or farming, from neighboring areas.

By 3,000 BCE, a continuity in the Neolithic spread brought Mediterranean-like ancestry to the Maghreb, most likely from Iberia. Other archaeological remains, such as African elephant ivory and ostrich eggs found in Iberian sites, confirm the existence of contacts and exchange networks through both sides of the Gibraltar strait at this time. Our analyses strongly support that at least some of the European ancestry observed today in North Africa is related to prehistoric migrations, and local Berber populations were already admixed with Europeans before the Roman conquest. Furthermore, additional European/ Iberian ancestry could have reached the Maghreb after KEB people; this scenario is supported by the presence of Iberian-like Bell-Beaker pottery in more recent stratigraphic layers of IAM and KEB caves. Future paleogenomic efforts in North Africa will further disentangle the complex history of migrations that forged the ancestry of the admixed populations we observe today.

north-africa-iberia-admixture
Ancestry inference in ancient samples from North Africa and the Iberian Peninsula. (B) ADMIXTURE analysis using the Human Origins dataset (European, Middle Eastern, and North African populations) for modern and ancient samples (K = 8). (D) Detail of ADMIXTURE analysis using the Human Origins dataset (European, Middle Eastern, North African, and sub-Saharan African populations) for modern and ancient samples, including Taforalt.

Also, from the main author’s Twitter account:

I just realized that the paragraph with information on data availability is missing! Sequence data in the European Nucleotide Archive (PRJEB22699). Consensus mtDNA sequences are available at the National Center of Biotechnology Information (Accession Numbers MF991431-MF991448).

I find it hard to believe that this genetic continuity from Upper Palaeolithic to Late Neolithic could be representative of an autochthonous development of Afroasiatic. An important population movement – likely more than one – must be found in ancient DNA influencing North-Central and North-East Africa, probably during the time of the Green Sahara corridor.

See here:

The Caucasus a genetic and cultural barrier; Yamna dominated by R1b-M269; Yamna settlers in Hungary cluster with Yamna

caucasus-europe

Open access The genetic prehistory of the Greater Caucasus, by Wang et al. bioRxiv (2018).

The Caucasus Mountains as a prehistoric barrier

I think the essential message we can extract from the paper is that the Caucasus was a long-lasting cultural and genetic barrier, although (obviously) it was not insurmontable.

Our results show that at the time of the eponymous grave mound of Maykop, the North Caucasus piedmont region was genetically connected to the south. Even without direct ancient DNA data from northern Mesopotamia, the new genetic evidence suggests an increased assimilation of Chalcolithic individuals from Iran, Anatolia and Armenia and those of the Eneolithic Caucasus during 6000-4000 calBCE23, and thus likely also intensified cultural connections. Within this sphere of interaction, it is possible that cultural influences and continuous subtle gene flow from the south formed the basis of Maykop.

caucasus-mountains-eneolithic
The zoomed map shows the location of sites in the Caucasus. The size of the circle reflects number of individuals that produced genome-wide data. The dashed line illustrates a hypothetical geographic border between genetically distinct Steppe and Caucasus clusters.

Also, unlike more recent times, the North Caucasian piedmont and foothill of the Caucasus region was more strongly connected to Northern Iran than to the steppe, at least until the Bronze Age.

(…) our data shows that the northern flanks were consistently linked to the Near East and had received multiple streams of gene flow from the south, as seen e.g. during the Maykop, Kura-Araxes and late phase of the North Caucasus culture.

Northern Caucasus dominated by R1b, southern Caucasus by J and G2

caucasus-y-dna
Comparison of Y-chromosome (A) 1123 and mitochondrial (B) haplogroup distribution in the Steppe and Caucasus cluster.

The first samples from the Eneolithic (one ca. 4300 BC?, the other ca. 4100 BC) are R1b1, without further subclades, so it is difficult to say if they were V88. On the PCA, they seem to be an important piece of the early Khvalynsk -> early Yamna transition period, since they cluster closer to (or even among) subsequent Yamna samples.

From 3000 BC onwards, all samples from the Northern Caucasus group of Yamna are R1b-M269, which right now is probably no surprise for anyone.

The Catacomb culture is dominated by R1b-Z2103, which agrees with what we saw in the unclassified Ukraine Eneolithic sample. However, the new samples (clustering close to Yamna, but with slightly ‘to the south’ of it) don’t seem to cluster closely to that first sample, so that one may still remain a real ‘outlier’, showing incoming influence (through exogamy) from the north.

If anyone was still wondering, no R1a in any of the samples, either. This, and the homogeneous R1b-Z2103 community in Catacomb (a culture in an intermediate region between Late Yamna to the West, and Poltavka to the East), together with Poltavka dominated by R1b-Z2103, too, should put an end to the idea that Steppe MLBA (Sintashta-Petrovka/Potapovka) somehow formed in the North Pontic steppe and appeared directly in the Volga-Ural region. A Uralic/Indo-Iranian community it is, then.

The admixed population from the Caucasus probably points to an isolated region of diverse peoples and languages even in this period, which justifies the strong differences among the historic language families attested in the Caucasus.

So, not much space for Anatolian migrating with those expected Maykop samples with EHG ancestry, unless exogamy is proposed as a source of language change.

PCA-caucasus
ADMIXTURE and PCA results, and chronological order of ancient Caucasus individuals. Samples from Hungary are surrounded by red circles (see below for ADMIXTURE data) (a) ADMIXTURE results (k=12) of the newly genotyped individuals (fillbred symbols with black outlines) sorted by genetic clusters (Steppe and Caucasus) and in chronological order (coloured bars indicate the relative archaeological dates, (b) white circles the mean calibrated radiocarbon date and the errors bars the 2-sigma range. (d) shows these projected onto a PCA of 84 modern-day West Eurasian populations (open symbols).

Yamna Hungary, and the previous Yamna “outliers”

Those western “Yamna outliers”, as I expected, were part of some late Khvalynsk/early Yamna groups that cluster “to the south” of eastern Yamna samples:

Another important observation is that all later individuals in the steppe region, starting with Yamnaya, deviate from the EHG-CHG admixture cline towards European populations in the West. This documents that these individuals had received Anatolian farmer-related ancestry, as documented by quantitative tests and recently also shown for two Yamnaya individuals from Ukraine (Ozera) and one from Bulgaria24. For the North Caucasus region, this genetic contribution could have occurred through immediate contact with groups in the Caucasus or further south. An alternative source, explaining the increase in WHG-related ancestry, would be contact with contemporaneous Chalcolithic/EBA farming groups at the western periphery of the Yamnaya culture distribution area, such as Globular Amphora and Tripolye (Cucuteni–Trypillia) individuals from Ukraine, which also have been shown to carry Anatolian Neolithic farmer-derived ancestry24.

On the other hand, it is interesting that – although no information is released about these samples – Yamna Bulgaria is now a clear outlier, among very “Yamnaya”-like Yamna settlers from Hungary, most likely from the Carpathian basin, and new Yamna LCA/EBA samples, possibly from Late Yamna (see them also marked in the PCA above):

yamnaya-hungary-admixture
Modified image, with red rectangles surrounding (unexplained) Hungarian samples (c) ADMIXTURE results of relevant prehistoric individuals mentioned in the text (filled symbols)

The important admixture of Yamna settlers with native populations, seen in expanding East Bell Beakers of R1b-L23 lineages from ca. 2500 BC on, must have therefore happened at the same time as the adoption of the proto-Bell Beaker package, i.e. precisely during the Carpathian Basin / Lower Danube settlements, and not in West Yamna.

yamnaya-hungary-lca-eba
Modified image, with red rectangles surrounding (unexplained) Yamna samples Modelling results for the Steppe and Caucasus cluster. Admixture proportions based on (temporally and geographically) distal and proximal models, showing additional Anatolian farmer-related ancestry in Steppe groups as well as additional gene flow from the south in some of the Steppe groups as well as the Caucasus groups

So, it can’t get clearer that Late Neolithic Baltic and Corded Ware migrants, sharing R1a-Z645 lineages and a different admixture, related to Eneolithic North Pontic groups such as Sredni Stog (see above ADMIXTURE graphics of CWC and Eneolithic Ukraine samples), did not come from West Yamna migrants, either.

So much for the R1a/R1b Yamna community that expanded Late PIE into Corded Ware.

NOTE. Andrew Gelman has coined a term for a curious phenomenon (taken from an anonymous commenter): “Eureka bias”, which refers not only to how researchers stick to previously reported incorrect results or interpretations, but also to how badly they react to criticism, even if they understand that it is well-founded. Directly applicable to the research groups that launched the Yamna-CWC idea (and the people who followed them) based on the fallacious “Yamnaya ancestry” concept, and who are still rooting for some version of it, from now on with exogamy, patron-client relationships, Eneolithic Indo-Slavonic, and whatnot. Unless, that is, Anthony’s latest model is right, and Yamna Hungary is suddenly full of R1a-Z645 samples…

Images used are from the article.

Related:

Iberia in the Copper and Early Bronze Age: Cultural, demographic, and environmental analysis

bell-beaker-ritual

New paper (behind paywall), Cultural, Demographic and Environmental Dynamics of the Copper and Early Bronze Age in Iberia (3300–1500 BC): Towards an Interregional Multiproxy Comparison at the Time of the 4.2 ky BP Event, Blanco-González, Lillios, López-Sáez, et al. J World Prehist (2018).

Abstract (emphasis mine):

This paper presents the first comprehensive pan-Iberian overview of one of the major episodes of cultural change in later prehistoric Iberia, the Copper to Bronze Age transition (c. 2400–1900 BC), and assesses its relationship to the 4.2 ky BP climatic event. It synthesizes available cultural, demographic and palaeoenvironmental evidence by region between 3300 and 1500 BC. Important variation can be discerned through this comparison. The demographic signatures of some regions, such as the Meseta and the southwest, diminished in the Early Bronze Age, while other regions, such as the southeast, display clear growth in human activities; the Atlantic areas in northern Iberia barely experienced any changes. This paper opens the door to climatic fluctuations and inter-regional demic movements within the Peninsula as plausible contributing drivers of particular historical dynamics.

iberia-culture-history-areas
Division of Iberia into 5 study areas according to their culture history (3300–1550 BC)

Interesting excerpts summarizing key trends in the different regions:

  • Between 2200 and 1900 BC, the northernmost regions (i.e. Galicia, the Cantabrian strip and the northeastern sector to the north of the Ebro valley) underwent relatively minor changes in the realms of settlement and burial practices. (…) In addition, some Atlantic areas show a marked and statistically significant fall in human activity c. 2200 BC, with a subsequent recovery c. 1600 BC, and such observations are matched by paleoenvironmental proxies and a lack of known EBA sites
  • The overall impression from the Meseta is one of sharp disruption in cultural practices; these include both settlement and burial patterns, abrupt shifts in local climate conditions, and striking differences in human pressure on vegetation. However, there was also clear intra-regional variability, with remarkable internal particularities and differential tempos between the western and eastern sectors. In terms of material culture, discontinuity with the Copper Age is the main trend in the western Duero and the Tagus valleys, yet EBA communities to the north of the Central System adopted far more distinctive and therefore traceable site types (hilltops) and material repertoire. This shift was even stronger in the case of the Motillas culture at La Mancha, whose pathway seems closely tied to the Argaric area.
  • Intra-regional variability is also apparent within the northeast (…) In the second millennium BC, material culture changed, long-distance exchange intensified and anthropogenic pressure increased, despite continuity in diverse realms of social practice.
  • The pattern in the southwest was one of marked discontinuity with two key features: a) it follows the general decreasing trends manifest across Atlantic Iberia; and b) its temporality was clearly different from the rest of the Peninsula and apparently unrelated to the 4.2 ky BP event. Thus, a highly conspicuous and rich variety of cultural expressions in the Chalcolithic, with an early and marked peak in human activity during the Beaker phase c. 2500 BC, gave way to a sudden cultural collapse prior to the onset of the EBA
  • The southeast exhibits one of the most remarkable cultural shifts in Western Europe. (…) The radical transformation in Chalcolithic materiality and ways of life could be regarded as a kind of societal collapse. The Argaric, a highly hierarchical and integrated regional polity, is the clearest example of a new scenario that emerged after the 4.2 ky BP event, yet the contributing role of environmental change and immigration from other regions remains to be fully explored.

Since R1b-DF27 lineages are widely distributed in modern western Europe, it is only logical that the recent find of its first ancient sample in Iberia has sparked the interest for Chalcolithic and Early Bronze Age Iberian cultures.

There is not much literature in English about Iberian prehistory, especially on the evolution of Bell Beaker culture. Also, most papers in Spanish on this cultural phenomenon – in my humble opinion, as a non-archaeologist – seem to be written from a merely descriptive archaeological point of view, many of them still sharing the radiocarbon-based assessment of origin and distribution of materials, instead of more complex anthropological models of cultural change and potential migrations.

Nevertheless, changes and influences in Iberian cultures are obvious regardless of the view taken on population movements (which are becoming quite clear now), and this paper seems to me a thorough review, very interesting for international researchers when interpreting ancient DNA from Iberia.

Featured image, modified from the paper: “The Bell Beaker culture in the northern Meseta: an artistic recreation of funerary ritual at Fuente Olmedo (Valladolid). Source: Garrido-Pena et al. 2011, Fig. 7.7”.

EDIT (21 MAR 2018): Interesting C14 date repository project Cronología de la Prehistoria de la Península Ibérica (read a brief description, in Spanish).

Related:

Iberian prehistoric migrations in Genomics from Neolithic, Chalcolithic, and Bronze Age

iberia-neolithic-bronze-age

New open access paper Four millennia of Iberian biomolecular prehistory illustrate the impact of prehistoric migrations at the far end of Eurasia, by Valdiosera, Günther, Vera-Rodríguez, et al. PNAS (2018) published ahead of print.

Abstract (emphasis mine)

Population genomic studies of ancient human remains have shown how modern-day European population structure has been shaped by a number of prehistoric migrations. The Neolithization of Europe has been associated with large-scale migrations from Anatolia, which was followed by migrations of herders from the Pontic steppe at the onset of the Bronze Age. Southwestern Europe was one of the last parts of the continent reached by these migrations, and modern-day populations from this region show intriguing similarities to the initial Neolithic migrants. Partly due to climatic conditions that are unfavorable for DNA preservation, regional studies on the Mediterranean remain challenging. Here, we present genome-wide sequence data from 13 individuals combined with stable isotope analysis from the north and south of Iberia covering a four-millennial temporal transect (7,500–3,500 BP). Early Iberian farmers and Early Central European farmers exhibit significant genetic differences, suggesting two independent fronts of the Neolithic expansion. The first Neolithic migrants that arrived in Iberia had low levels of genetic diversity, potentially reflecting a small number of individuals; this diversity gradually increased over time from mixing with local hunter-gatherers and potential population expansion. The impact of post-Neolithic migrations on Iberia was much smaller than for the rest of the continent, showing little external influence from the Neolithic to the Bronze Age. Paleodietary reconstruction shows that these populations have a remarkable degree of dietary homogeneity across space and time, suggesting a strong reliance on terrestrial food resources despite changing culture and genetic make-up.

iberia-admixture
(A) f4 statistics testing affinities of prehistoric European farmers to either early Neolithic Iberians or central Europeans, restricting these reference populations to SNP-captured individuals to avoid technical artifacts driving the affinities. The boxplots in A show the distributions of all individual f4 statistics belonging to the respective groups. The signal is not sensitive to the choice of reference populations and is not driven by hunter-gatherer–related admixture (Datasets S4 and S5). (B) Estimates of ancestry proportions in different prehistoric Europeans as well as modern southwestern Europeans. Individuals from regions of Iberia were grouped together for the analysis in A and B to increase sample sizes per group and reduce noise

Conclusion:

We present a comprehensive biomolecular dataset spanning four millennia of prehistory across the whole Iberian Peninsula. Our results highlight the power of archaeogenomic studies focusing on specific regions and covering a temporal transect. The 4,000 y of prehistory in Iberia were shaped by major chronological changes but with little geographic substructure within the Peninsula. The subtle but clear genetic differences between early Neolithic Iberian farmers and early Neolithic central European farmers point toward two independent migrations, potentially originating from two slightly different source populations. These populations followed different routes, one along the Mediterranean coast, giving rise to early Neolithic Iberian farmers, and one via mainland Europe forming early Neolithic central European farmers. This directly links all Neolithic Iberians with the first migrants that arrived with the initial Mediterranean Neolithic wave of expansion. These Iberians mixed with local hunter-gatherers (but maintained farming/pastoral subsistence strategies, i.e., diet), leading to a recovery from the loss of genetic diversity emerging from the initial migration founder bottleneck. Only after the spread of Bell Beaker pottery did steppe-related ancestry arrive in Iberia, where it had smaller contributions to the population compared with the impact that it had in central Europe. This implies that the two prehistoric migrations causing major population turnovers in central Europe had differential effects at the southwestern edge of their distribution: The Neolithic migrations caused substantial changes in the Iberian gene pool (the introduction of agriculture by farmers) (6, 9, 11, 13, 24), whereas the impact of Bronze Age migrations (Yamnaya) was significantly smaller in Iberia than in north-central Europe (24). The post-Neolithic prehistory of Iberia is generally characterized by interactions between residents rather than by migrations from other parts of Europe, resulting in relative genetic continuity, while most other regions were subject to major genetic turnovers after the Neolithic (4, 6, 7, 9, 25, 48). Although Iberian populations represent the furthest wave of Neolithic expansion in the westernmost Mediterranean, the subsequent populations maintain a surprisingly high genetic legacy of the original pioneer farming migrants from the east compared with their central European counterparts. This counterintuitive result emphasizes the importance of in-depth diachronic studies in all parts of the continent.

Related:

Population replacement in Early Neolithic Britain, and new Bell Beaker SNPs

copper-age-late-bell-beaker

New (copyrighted) preprint at BioRxiv, Population Replacement in Early Neolithic Britain, by Brace et al. (2018).

Abstract (emphasis mine):

The roles of migration, admixture and acculturation in the European transition to farming have been debated for over 100 years. Genome-wide ancient DNA studies indicate predominantly Anatolian ancestry for continental Neolithic farmers, but also variable admixture with local Mesolithic hunter-gatherers. Neolithic cultures first appear in Britain c. 6000 years ago (kBP), a millennium after they appear in adjacent areas of northwestern continental Europe. However, the pattern and process of the British Neolithic transition remains unclear. We assembled genome-wide data from six Mesolithic and 67 Neolithic individuals found in Britain, dating from 10.5-4.5 kBP, a dataset that includes 22 newly reported individuals and the first genomic data from British Mesolithic hunter-gatherers. Our analyses reveals persistent genetic affinities between Mesolithic British and Western European hunter-gatherers over a period spanning Britain’s separation from continental Europe. We find overwhelming support for agriculture being introduced by incoming continental farmers, with small and geographically structured levels of additional hunter-gatherer introgression. We find genetic affinity between British and Iberian Neolithic populations indicating that British Neolithic people derived much of their ancestry from Anatolian farmers who originally followed the Mediterranean route of dispersal and likely entered Britain from northwestern mainland Europe.

Also, Genetiker has updated Y-SNP calls from new data published from the Harvard group.

The R1b lineages that expanded from (Yamna->) East Bell Beakers -> Western Europe are more and more clearly of R1b-L151 subclades, as expected.

Quite interesting are the early samples from Poland, of R1b1a1a2a2-Z2103 and R1b1a1a2a1a-L151 lineages – , which may point (different to the more homogeneous L151 distribution in Western Europe) to a mix in both original (east-west) Yamna groups. This could tentatively be used to explain the Graeco-Aryan influence that some linguists see in Balto-Slavic (or its superstrate).

That link would then be quite early, to account for an influence during the Yamna settlements in Hungary, before its expansion as East Bell Beakers, but we haven’t seen a clearly differentiated subgroup (yet) in Archaeology, Anthropology, or Genomics within the Hungarian Yamna/East Bell Beaker community, so I am not convinced. It could be just that different scattered subclades mixed with the general L151 population pop up (following old Yamna lineages, or having being added along the way), as expected in an expansion over such a great territory – as if some scattered samples of R1a, I1, I2, J, etc. were found.

We need more early samples from south-eastern Europe and the steppe during the Chalcolithic to ascertain the composition and migration paths of the different Yamna settlers.

Other interesting findings are the early (Proto-)Bell Beaker samples of haplogroup R1b with no steppe ancestry from Spain – which some autochthonous continuists wanted to believe was a proof of some kind – , which are actually R1b-V88, a haplogroup known to have expanded throughout Europe quite early. In fact, this subclade has been recently shown to have most likely expanded through the Green Sahara region, and is potentially linked to the expansion of Afro-Asiatic.

See also:

Demographic research of Neolithic, Chalcolithic, and Bronze Age Europe

europe-demographic

I mentioned in the Indo-European demic diffusion model the need to assess absolute and relative population growth – as well as other demographic changes – to interpret genomic data from the different European regions studied.

One article I referred to was Demographic traces of technological innovation, social change and mobility: from 1 to 8 million Europeans (6000–2000 BCE), by Johannes Müller.

Excerpts (emphasis mine):

  • The neolithization of Northern and Northwestern Europe (probably with new forms of slash-and-burn agriculture; Feeser et al. 2012; Schier 2009) was also one of the causes for the population increase observed.
  • The introduction of the plough and developing technologies (e.g. the introduction of the wheel) (cf. Mischka 2011) might also be causes of rising population figures from ca. 3500–3000 BC.
  • The establishment of subcontinental value systems, such as the Corded Ware and Bell-Beaker phenomena (Czebreszuk/Szmyt 2003; Furholt 2004), in contrast to regional identities, might have triggered different reactions in different areas, leading to fluctuating population levels.
  • The introduction of Bronze Age ideologies, including bronze as a technology, triggered the spread of Neolithic and Bronze Age societies to vast areas of Europe (e.g. Earle/Kristiansen 2010).A major population increase is observed in both the areas already settled as well as in new areas of interest.
europe-population-neolithic
Absolute population values in Europe and the Near East from 6500–1500 BCE (interpolation line: spline).

In our population estimations for Central Europe and Scandinavia, population increases are associated with the periods from 5500–5000 BCE (LBK) and 3500–3000 BCE (middle and late Funnelbeaker Culture), but not for the period from 2500–2000 BCE (Bell Beaker). Consequently, this would possibly indicate forms of immigration for the first two periods and a form of interregional networking (e.g. through marriage) for the latter. But as also for the first cases on the supra-regional level (which our enquiries investigated), no other area with a significant population decrease could be observed, therefore “proof” for larger population displacement is not given. For such inquiries, studies on a more regional level are probably necessary. Nevertheless, for the Bell Beaker period I would like to exclude the possibility of large population influxes at least to Central Europe and South Scandinavia as the population values show no indication of such an event (cf. Fig. 10). In consequence, supra-regional networks or population-exchanges between smaller regions might be responsible for the isotope values.

One could interpret from the graphics, including known anthropological and genomic data, that:

  • The population growth corresponding to the Corded Ware expansion from ca. 3300 into Central Europe was seen initially with the introduction of new technology, but then stalled – probably with population replacement during the A-horizon of the Corded Ware culture.
  • The Yamna expansion into South-East Europe must have included some population replacement, i.e. influx into progressively deserted areas (such as that of the Cucuteni-Trypillia culture), since it did not leave traces of population growth.
  • The impact of the expansion of East Bell Beakers from ca. 2500 BC is clear in South-East Europe, and especially in Western Europe – taking into account the whole population growth in Europe. In Central Europe and Scandinavia the overall impact of BB migration was more limited, which suggests some degree of population replacement.

Also important to interpret genomic data are the actual economic and social differences in the different periods and cultures – usually growing after the introduction of farming. A good example is the scarce data from Khvalynsk, where the sample of haplogroup R1b (most likely of subclade M269) shows – apart from a closer position in PCA to Yamna – a a high-status burial, similar to high-status individuals buried under kurgans in later Yamna graves. This man was therefore probably a founder of an elite group of patrilineally-related families, which dominated in the following Yamna culture, which explains the clear expansion of this haplogroup’s subclades from this region.

europe-population-inequality
Figures from Rebellion and Inequality in Archaeology (2017), by Johannes Müller

Other interesting papers on European demographics by Johannes Müller include:

Check out also works by Marko Porčić (such as Radiocarbon test for demographic events in written and oral history) or Stephen Shennan.

EDIT (17 Feb 2018): For how variation in the effective population size governs genetic diversity, see:

Featured image, from the main article: “The distribution of agrarian regions in Europe and the Near East in relation to the supra-regions as defined in this study: Near East (NE) about 2.400.000 km2; South East Europe (SEE) about 1.087500 km2; Central Europe and South Scandinavia (CE/SSc) about 1.613.000 km2. Europe includes 10.050.000 km2 (without Iceland)”.

See also:

Genetic prehistory of the Baltic Sea region and Y-DNA: Corded Ware and R1a-Z645, Bronze Age and N1c

baltic-region-mittnik

Open Access The genetic prehistory of the Baltic Sea region, by Mittnik et al., Nature Communications 9: 442 (2018), based on preprint The Genetic History of Northern Europe, at BioRxirv.

As you can see, it follows my predictions in terms of haplogroups, and sadly the same trend to substitute ‘Yamna’ for ‘steppe’ while keeping linguistic interpretations unchanged…

Important excerpts for the Indo-European question (emphasis mine):

Mesolithic to Neolithic

In the archaeological understanding, the transition from Mesolithic to Neolithic in the Eastern Baltic region does not coincide with a large-scale population turnover and a stark shift in economy as seen in Central and Southern Europe. Rather, it is signified by a change in networks of contacts and the use of pottery, among other material, cultural and economic changes. Our results suggest continued admixture between groups in the south of the Eastern Baltic region, who are more closely related to WHG, and northern or eastern groups, more closely related to EHG. Neolithic social networks from the Eastern Baltic to the River Volga could also explain similarities of the hunter-gatherer pottery styles, although morphologically analogous ceramics might also have developed independently due to similar functionality. The genetic evidence for a change in networks and possibly even a large-scale population movement is most pronounced in the Middle Neolithic in individuals attributed to the CCC. The distribution of this culture overlaps in the north with the Narva culture and extends further north to Finland and Karelia. Its spread in the Eastern Baltic is linked with a significant change in imported raw materials, artefacts, and the appearance of village-like settlements15.

Neolithic to Chalcolithic

We see a further population movement into the regions surrounding the Baltic Sea with the CWC in the Late Neolithic that was accompanied by the first evidence of extensive animal husbandry in the Eastern Baltic. The presence of ancestry from the Pontic-Caspian Steppe among Baltic CWC individuals without the genetic component from north-western Anatolian Neolithic farmers must be due to a direct migration of steppe pastoralists that did not pick up this ancestry in Central Europe. It suggests import of the new economy by an incoming steppe-like population independent of the agricultural societies that were already established to the south and west of the Baltic Sea. The presence of direct contacts to the steppe could lend support to a linguistic model that sees an early branching of Balto-Slavic from a Proto-Indo-European language, for which the west Eurasian steppe was proposed as a homeland. However, as farmer ancestry is found in later Eastern Baltic individuals, it is likely that considerable individual mobility and a network of contact throughout the range of the CWC facilitated its spread eastward, possibly through exogamous marriage practices. Conversely, the appearance of mitochondrial haplogroup U4 in the Central European Late Neolithic after millennia of absence could indicate female gene-flow from the Eastern Baltic, where this haplogroup was present at high frequency.

baltic-neolithic
PCA and ADMIXTURE analysis reflecting Late Neolithic in Northern European prehistory. a Principal components analysis of 1012 present-day West Eurasians (grey points, modern Baltic populations in dark grey) with 294 projected published ancient and ancient North European samples introduced in this study (marked with a red outline). b Ancestral components in ancient individuals estimated by ADMIXTURE (k = 11)
baltic-samples-neolithic
Zoomed-in version of the European Late Neolithic PCA.

So, we see that no farmer ancestry is found in the Baltic (unlike in Western Yamna), that PCA of Late Neolithic is closer to Corded Ware samples from Europe (or to earlier samples from the region) and not to Yamna, as suggested at first by the Zvejnieki individual.

There obviously was exogamy – which may in fact justify the findings in PCA close to Yamna (like the Zvejnieki sample), although researchers obviate that.

Also, as expected, no R1b-M269 in the Baltic (during the Corded Ware period), most are R1a with the majority showing subclade R1a-Z645 (and others poor SNP coverage), which support the reduction in haplogroup diversity to this very subclade during the expansion of Corded Ware peoples, as I predicted it would happen.

Bronze Age

Local foraging societies were, however, not completely replaced and contributed a substantial proportion to the ancestry of Eastern Baltic individuals of the latest LN and Bronze Age. This ‘resurgence’ of hunter-gatherer ancestry in the local population through admixture between foraging and farming groups recalls the same phenomenon observed in the European Middle Neolithic and is responsible for the unique genetic signature of modern-day Eastern Baltic populations.

We suggest that the Siberian and East Asian related ancestry in Estonia, and Y-haplogroup N in north-eastern Europe, where it is widespread today, arrived there after the Bronze Age, ca. 500 calBCE, as we detect neither in our Bronze Age samples from Lithuania and Latvia. As Uralic speaking populations of the Volga-Ural region show high frequencies of haplogroup N, a connection was proposed with the spread of Uralic language speakers from the east that contributed to the male gene pool of Eastern Baltic populations and left linguistic descendants in the Finno-Ugric languages Finnish and Estonian. A potential future direction of research is the identification of the proximate population that contributed to the arrival of this eastern ancestry into Northern Europe.

I predicted that haplogroup N arrived probably to the region west of the Urals with the Sejma-Turbino phenomenon, and that it expanded quite late, probably through founder effects. A late arrival to the region leaves obviously (safe for these researchers and others working with old ideas) only the Corded Ware culture (represented by steppe admixture and mainly haplogroup R1a-Z645) as the vector of expansion of Uralic languages, which show obviously a dialectalization process and regional expansion much older than 500 BC…

It is funny to see how people keep trying to identify R1a with ‘Yamnaya’, now ‘steppe’, but always Indo-European (an ethnolinguistic term, mind you) supposedly because of the ‘Yamnaya’ (now ‘steppe’) admixture, but the only ‘mark’ of Uralic languages for the same researchers in the same paper using this very concept is nevertheless, paradoxically, haplogroup N, with an assumption explicitly based on prevalence in modern populations

This admixture vs. haplogroup question for language and culture identification in genetic papers is really gettting messed up with new data, now in a contortionist-like way…

Images and text: Content of the paper is licensed under CC-by 4.0.

See also: