The fast spread of Neolithic farmers in the western Mediterranean

Recent open access Symbols in motion: Flexible cultural boundaries and the fast spread of the Neolithic in the western Mediterranean, by Rigaud, Manen, García-Martínez de Lagrán, PLOS One (2018).

Abstract (emphasis mine):

The rapid diffusion of farming technologies in the western Mediterranean raises questions about the mechanisms that drove the development of intensive contact networks and circulation routes between incoming Neolithic communities. Using a statistical method to analyze a brand-new set of cultural and chronological data, we document the large-scale processes that led to variations between Mediterranean archaeological cultures, and micro-scale processes responsible for the transmission of cultural practices within farming communities. The analysis of two symbolic productions, pottery decorations and personal ornaments, shed light on the complex interactions developed by Early Neolithic farmers in the western Mediterranean area. Pottery decoration diversity correlates with local processes of circulation and exchange, resulting in the emergence and the persistence of stylistic and symbolic boundaries between groups, while personal ornaments reflect extensive networks and the high level of mobility of Early Neolithic farmers. The two symbolic productions express different degrees of cultural interaction that may have facilitated the successful and rapid expansion of early farming societies in the western Mediterranean.

neolithisation-mediterranean
Mean Inverse Distance Weighting (IDW) interpolation of the first two axes of the Principal Coordinates Analysis (Figure D in S1 File). Diversity of the pottery attributes (A) and bead-type associations (B) express two different cultural geographies. Maps were made by S. R. using the software QGIS 2.6.1 and Etopo1 Digital Elevation Model [110]. https://doi.org/10.1371/journal.pone.0196488.g002.
The maps of interpolated pottery decorative techniques and bead-type diversities throughout the western Mediterranean show the highest interpolated values in southern Italy (Fig B). Hotspots restricted to the east of the Rhône Valley in southern France and eastern Iberia are also visible on the map of bead-type association diversity. Conversely, southern France and eastern Iberia are characterized by lower interpolated values on the map of pottery decorative techniques diversity (Fig A).

Conclusions:

Our results shed light on the cultural mechanisms responsible for the complex cultural geography of the western Mediterranean during the transition to farming. Pottery decorations participated in restrained networks in which geographical proximity and local processes of transmission played an influential role. Bead-type associations were used to tell multiple stories about social identities, were especially resistant to change and are characterized by a greater stability through time and space. The high level of cultural connection between the early farming communities favored movement, interaction and exploration and likely represented a successful strategy for their rapid expansion in the western Mediterranean. Cultural boundaries persisted despite a flow of individuals and symbolic transfer across them.

Genetic studies indicate that the last foragers and the first farmers developed social and cultural relationships more closely tied than previously indicated through components of the material culture [139]. Biological data and chronological models support a pattern of diffusion implying geographically discontinuous contacts between local foragers and incoming farmers, but repeated in time [9,140,141]. This process of diffusion conjointly occurred with changes in material culture, including pottery decorations and personal ornaments. Pottery production represents a technological innovation mostly associated with the Neolithic way of life in the western Mediterranean. Pottery decorations were likely particularly sensitive to interactions, leading to their high variability in time and space in order to reinforce group membership. Conversely, personal ornaments were less inclined to change in space and time. Their production by both local foragers and incoming farmers implies different cultural readjustments that led to a completely different pattern of variation in time and space. The preservation of the foragers’ personal ornament styles (and likely also meanings) within emerging farming communities [20,58] has probably contributed to the maintenance of their stability through time and space.

The two symbolic productions appear as a polythetic set of cultural behaviors dedicated to mediating early farmer identities in many ways, and personal ornaments likely reflected the most entrenched and lasting facets of farmers’ ethnicity.

This research is similar to the recent one by Kılınç et al. (2018) studying the same processes initially in Anatolia and the Aegean. With this one it may also be concluded that Archaeology is necessary to assess meaningful cultural (and thus potential ethnolinguistic) change, beyond gross genetic inflows, even in the case of the Near Eastern farmer expansion waves.

Related:

Language continuity despite population replacement in Remote Oceania

ancientdna-migrations-vanuatu

New article (behind paywall) Language continuity despite population replacement in Remote Oceania, by Posth et al., Nat. Ecol. Evol. (2018).

Abstract:

Recent genomic analyses show that the earliest peoples reaching Remote Oceania—associated with Austronesian-speaking Lapita culture—were almost completely East Asian, without detectable Papuan ancestry. However, Papuan-related genetic ancestry is found across present-day Pacific populations, indicating that peoples from Near Oceania have played a significant, but largely unknown, ancestral role. Here, new genome-wide data from 19 ancient South Pacific individuals provide direct evidence of a so-far undescribed Papuan expansion into Remote Oceania starting ~2,500 yr BP, far earlier than previously estimated and supporting a model from historical linguistics. New genome-wide data from 27 contemporary ni-Vanuatu demonstrate a subsequent and almost complete replacement of Lapita-Austronesian by Near Oceanian ancestry. Despite this massive demographic change, incoming Papuan languages did not replace Austronesian languages. Population replacement with language continuity is extremely rare—if not unprecedented—in human history. Our analyses show that rather than one large-scale event, the process was incremental and complex, with repeated migrations and sex-biased admixture with peoples from the Bismarck Archipelago.

So, despite the population replacement in Oceania seen recently in Genomics, the people of present-day Vanuatu continue to speak languages descended from those spoken by the initial Austronesian inhabitants, rather than any Papuan language of the incoming migrants.

Professor Gray, Director of the Department of Linguistic and Cultural Evolution at the MPI-SHH, says:

Population replacement with language continuity is extremely rare – if not unprecedented – in human history. The linguist Bob Blust has long argued for a model in which a separate Papuan expansion reaches Vanuatu soon after initial Austronesian settlement, with the initial, and likely undifferentiated, Austronesian language surviving as a lingua franca for diverse Papuan migrant groups.

Dr. Adam Powell, senior author of the study and also of the MPI-SHH, continues,

The demographic history suggested by our ancient DNA analyses provides really strong support for this historical linguistic model, with the early arrival and complex, incremental process of genetic replacement by people from the Bismarck Archipelago. This provides a compelling explanation for the continuity of Austronesian languages despite the almost complete replacement of the initial genetic ancestry of Vanuatu.

ancient-dna-migrations-oceania
Maps showing the migrations in the area, including, in the final map, the migrations revealed by the current study. Credit: Hans Sell, adapted from Skoglund et al. Genomic insights into the peopling of the Southwest Pacific. Nature (2016).

I think we can safely disagree now with their assertion. We are seeing more and more cases of language continuity in spite of population replacement quite clearly in Eurasian prehistory. At least:

All these cases can be explained with founder effects and gradual expansions after an initial arrival, maybe also initial close interaction between different ethnic groups, where one group (and its language) becomes the dominant one.

NOTE. Even if an alternative model is selected (say, that Corded Ware migrants spoke Indo-European languages), alternative language continuity events need to be proposed for some of these regions, so we are beyond their description as ‘rare language events’ already.

What is becoming clearer with ancient samples, therefore, is that there is little space for prehistoric cultural diffusion events (at least massive ones), which were quite popular explanations before the advent of genetic studies.

Related:

Migration, acculturation, and the maintenance of between-group cultural variation

Preprint at BioRxiv, Migration, acculturation, and the maintenance of between-group cultural variation, by Alex Mesoudi (2017)

Abstract:

How do migration and acculturation affect within- and between-group cultural variation? Classic models from population genetics show that migration rapidly breaks down between-group genetic structure. However, in the case of cultural evolution, migrants (or their children) can acculturate to local cultural behaviors via social learning processes such as conformity, potentially preventing migration from eliminating between-group cultural variation. To explore this verbal claim formally, here I present models that quantify the effect of migration and acculturation on between-group cultural variation, first for a neutral trait and then for an individually-costly cooperative trait. I also review the empirical literature on the strength of migrant acculturation. The models show that surprisingly little conformist acculturation is required to maintain plausible amounts of between-group cultural diversity. Acculturation is countered by assortation, the tendency for individuals to preferentially interact with culturally-similar others. Cooperative traits may also be maintained by payoff-biased social learning but only in the presence of strong sanctioning institutions. While these models provide insight into the potential dynamics of acculturation and migration in cultural evolution, they also highlight the need for more empirical research into the individual-level learning biases that underlie migrant acculturation.

The Indo-European Corded Ware Theory group might need to resort to cultural diffusion models again after the ‘Yamnaya ancestral component’ is dismissed as a source for Corded Ware peoples and their migration.

Therefore, if you are somehow interested in keeping this IE-CWC(-R1a) theory alive, learning more about these theoritical models for cultural diffusion is probably your best investment for the future…

Related:

Another nail in the coffin for the Anatolian hypothesis: continuity and isolation in the Caucasus during the Neolithic and Calcholithic, in mtDNA samples

caucasus-armenia

A new paper appeared on Current Biology, by Margaryan et al. (including Morten E. Allentoft): Eight Millennia of Matrilineal Genetic Continuity in the South Caucasus.

Among its conclusions:

The plot clearly shows the clustering of the ancient group together with the modern European, Armenian, and Caucasian populations. We observe none of the typical East Eurasian mtDNA lineages (A, C, D, F, G, and M) among the ancient individuals, and only one individual with haplogroup D is present in the modern Armenian maternal gene pool (Artsakh). As such, the archaeologically and historically attested migrations of Central Asian groups (e.g., Turks and Mongols) into the South Caucasus [14, 15] do not seem to have had a major contribution in the maternal gene pool of Armenians. Both geographic (mountainous area) and cultural (Indo-European-speaking Christians and Turkic-speaking Muslims) factors could have served as barriers for genetic contacts between Armenians and Muslim invaders in the 11th–14th centuries CE. The same pattern was observed using Y chromosome markers in geographically diverse Armenian groups.

Also, regarding the potential Indo-European migration into the area:

It appears that during the last eight millennia, there were no major genetic turnovers in the female gene pool in the South Caucasus, despite multiple well-documented cultural changes in the region [27, 28]. This is in contrast to the dramatic shifts of mtDNA lineages occurring in Central Europe during the same time period, which suggests either a different mode of cultural change in the two regions or that the genetic turnovers simply occurred later in Europe compared to the South Caucasus. More data from earlier Mesolithic cultures in the South Caucasus are needed to clarify this. During the highly dynamic Bronze Age and Iron Age periods, with the formation of complex societies and the emergence of distinctive cultures such as Kura-Araxes, Trialeti-Vanadsor, Sevan-Artsakh, Karmir-Berd, Karmir-Vank, Lchashen-Metsamor, and Urartian, we cannot document any changes in the female gene pool. This supports a cultural diffusion model in the South Caucasus, unless the demographic changes were heavily male biased, as was most likely the case in Europe during the Bronze Age migrations [29, 30]. However, genome-wide data from the few Bronze Age individuals published so far from the South Caucasus also support a continuity scenario [26]. Another possibility is that any gene flow into the South Caucasus occurred from groups with a very similar genetic composition, facilitating only subtle genetic changes that are not detectable with the current datasets.

I would obviously support the latter possibility, a demic diffusion that can be shown by precise subclade and admixture analyses, because cultural diffusion is quite difficult to justify in any ancient setting. Since it is most likely south-eastern European R1b-Z2103 lineages (or R1b-M269, if resurged during the proto-language transition in the Balkans) the original marker of Palaeo-Balkan speakers, that is what one should be looking for in Y-DNA investigation in the area. Since migrations were probably male-biased, it is not likely that mtDNA was much affected. But, especially during the Iron Age, a change should also be seen, marked by the appearance of (recent) U subclades.

Related:

The Aryan migration debate, the Out of India models, and the modern “indigenous Indo-Aryan” sectarianism

On the origin of R1a and R1b subclades in Greece

News of the article seen first in Eurogenes (you can see the specific samples there).

Featured image is from the article.