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Prehistoric Migrations

Prehistoric Migrations

A blog dedicated to Neolithic and Bronze Age migrations in Europe

Interview by Craig Encer, Anglo-Turkish Society

1- What was the title of your phd and did your higher education in British Universities open new doors for you?

My PhD, which I defended in 2014 at the University of Liverpool, was on the Diffusion of Neolithic practices from Anatolia to Europe - looking at the sort of residential and construction practices associated with the introduction of farming and sedentism in Anatolia and Southeast Europe about eight to ten thousand years ago. I am very fortunate that two of my PhD supervisors, David Shankland and Douglas Baird, were present at the ‘Archaeology in Anatolia’ Symposium on 10th February.

I moved to the UK when I was 17 to take up a BA in Archaeology and Anthropology at the University of Bristol; in total, I studied in British Universities for nearly ten years, when fees where still affordable. I have a lot of admiration for the UK higher education system, which prepares very well for research and academic independence. It was in my first year at Bristol University that I heard Ian Hodder talk about Çatalhöyük: that sparked my interest in the Anatolian Neolithic. I have since been able to work at Çatalhöyük and other Neolithic sites in Turkey, thanks to the BIAA and other sponsors.

2- You are now specialising in Paleo-genetics and linking that with archaeological interpretations. Clearly this is a new field as extracting genetic material from the Neolithic period is only recently feasible. Are the reasonable preservation of bones and teeth sufficient criteria to extract meaningful DNA or does it require extra special circumstances to preserve segments long enough for it to be useful. How is the Anatolian climate and geography conducive to these preservation criteria?

I am currently based in a Palaeogenetics laboratory in Mainz, Germany, led by Joachim Burger, who coordinated a major training network for young researchers in 2012-2016 focused on ‘Bridging the European and Anatolian Neolithic’ (BEAN). As an archaeologist, I am mainly trying to catch up with the latest biomolecular revolution in science – full-genome ancient DNA sequencing since about 2010 and target-enriched aDNA extraction since 2015 – which enables the study of finer genetic variations between less differentiated ancient skeletons (for instance from the same archaeological site) and more complex population and demographic inferences.

A lot of what I do is learning how the new science works, both theoretically and practically. While ancient DNA extraction is a new technique, population genetics is a whole branch of science, over 100 years old, so I am having to adapt to different (model-driven) ways of thinking about populations and mobility in the past. Archaeology also deals with ‘populations’ (mainly of pots), so there is some overlap with population genetics, but not much. Never trust anyone who says that genes don’t lie; inference is not the same as interpretation, in evolutionary genetics, like in any other data-driven science: hypotheses laid out at the beginning can be tested, but the interpretation has to consider the samples that people choose to sequence and the depth of coverage of the palaeogenomes.

The genetic study of ancient populations in Anatolia is still in its infancy. There are major challenges. For the Neolithic period, entire regions like the Aegean coast of Turkey lack human bones, and cannot be integrated in broader syntheses. DNA degrades faster when exposed to warm conditions, so the Southeast of Turkey remains a genetic terra incognita. We know that some practices like the secondary manipulation of human bones and skeletons in Neolithic times, which were curated or left outside to dry for a period of time before being re-buried, also led to major loss of ancient DNA. Still, the Neolithic site of Barcın Höyük near Yenişehir in Northwest Anatolia has produced dozens of well-preserved higher-coverage genomes, which are now frequently discussed in relation to the spread of early farmers in Eurasia.

In the future we will be able to extract DNA from sediment samples and gain insight into the people who actually lived inside Neolithic villages – and not just those who were buried there. I wonder if these were the same people.

3- Gordon Childe’s ‘Neolithic Revolution’ definition based on a ‘productive economy based on farming and herding’ espoused first in 1936 still holds water today, but clearly there are modern nuances on this. His book published in 1950 ‘Prehistoric migrations in Europe’ also postulated the theory still broadly accepted today of migration from the Middle East to Europe. Considering the limited material he worked in his day, what did Childe get wrong in his postulations?

In the Western Academic tradition a society is said to be ‘neolithic’ if it produces its own food-supply and goods are consumed where they are produced, within a domestic sphere of production. Childe was instrumental in getting this definition more broadly accepted. Confusingly, in Russia, ‘Neolithic’ may refer to pottery-producing societies with or without agriculture, so it’s important to be clear about what is meant by ‘Neolithic’.

Agriculture is still regarded as a major innovation of the Neolithic period, but increasingly, it is becoming clear that the initial steps of farming adoption, for instance at 9th millennium BC Boncuklu in the Konya Plain, only consisted of low-level food production, and there was still a lot of hunting and gathering involved – as Douglas Baird has shown in his talk. It is not clear when the Neolithic economy became fully productive in Anatolia, but perhaps not until the late 8th millennium BC at Çatalhöyük, when large-scale mixed farming involving plants and livestock, was introduced.

With regard to Childe and the question of prehistoric migrations, one has to consider that he had very little empirical evidence at his disposal. The two major Anatolian Neolithic sites of Hacılar and Çatalhöyük were only discovered by his UCL former student James Mellaart after 1956, when Childe had already returned to Australia and committed suicide. Childe briefly worked as a trench supervisor at Mersin in the 1940s under his colleague John Garstang, so his model imagined that early farmers had essentially travelled by sea-route along the Mediterranean coast-line, bypassing the Anatolian Plateau to reach the Aegean. There is some confusion about this, because Childe also wrote about the ‘Anatolian rails’ that lead to Central Asia, so he was not averse to the land-route hypothesis. We now know that both land- and sea-routes were involved in Neolithic migrations.

4- You have been involved in a lot of recent excavations across Western Anatolia and in none of the sites is there evidence to date of food production before 6.600 BC, so around 2000 years after Central Anatolia based on radio-carbon dating of these levels. Discounting the remote possibility of sites still not found in Western Anatolia and the fact that all the various elements of the Neolithic Revolution appear at the same time in this Western zone, do you think the actual migration of the population bringing in all these various elements of life-style is more likely as opposed to ‘cross-border community diffusion’?

There are still very few detailed studies of plant and animal remains in Western Anatolia; the first indications are that new domestic species and patterns of subsistence arrived c. 6,600 BC fully-formed or ‘packaged’ with first farmers, who settled in previously uninhabited locations. We still don’t know who these farmers were, because as I said earlier there are very few human remains from sites on the Aegean coast of Turkey – none have been sequenced for DNA. In the Eastern Marmara region, we know that the first farmers at Barcın Höyük shared significant levels of genetic ancestry with early agriculturalists at Boncuklu, on the Central Anatolian plateau; so we assume that migration was a key driver in early agricultural dispersals.

5- The Lepenski-Vir (Danube Gorges) region was excavated by Dragoslav Srejovic during 1965-70 showing pottery introduced to the site around 6.200 BC when the first trapezoidal houses were built and burial customs change and also domesticates were introduced around 6.000 BC. This Mesolithic / Neolithic transition alluded to in this region has been intensively studied since with stable isotope analysis of human remains showing a divergence of Nitrogen isotope levels at around this juncture time. Is there a danger of assigning this directly to new-comers to the area from the East and could there be other factors at work, such as micro-region based diet?

Human skeletons from the Danube Gorges in the Central Balkans have been so intensively analysed with biomolecular approaches (stable isotopes and ancient DNA) over the last thirty years that we can start piecing together detailed biographies of final Holocene foragers and early farmers.

There is indeed a danger in assuming that people who have a Nitrogen-rich diet associated with longer food-chains, either fishing or a lot of hunting, are necessarily indigenous, while those with a more restricted farming-like terrestrial C3 plant food diet are immigrants. The picture is likely to be more complex as I explained in my talk. Two independent ancient DNA studies have now confirmed that several individuals buried at Lepenski Vir after 6,200 BC had a typical Anatolian (Barcın) ancestry background – suggesting that they were kidnapped or married into forager communities. These include a number of females and children. Some retain a farmer-like isotopic signature at death, suggesting a farming diet, others show a more contrasted picture. Age and gender are likely to have been important factors in deciding who eats what and when.

6- Current evidence seems to point to a major wave of agricultural practice dispersal beyond the Anatolian plateau from 6.600 BC onwards westwards, at least partly accompanied by people’s migration over 2000 years right up to Britain. Could climate change be part of this drive, perhaps compounded by the reduction of trees by the growing populations? Is there also any evidence for a similar spread northwards towards present day Russia?

There was a global climate anomaly around 6,200 BC, when massive amounts of meltwater from the Hudson Bay were discharged into the North Atlantic, potentially amplifying the atmospheric cooling observed during one of the Holocene rapid climate change intervals, c. 6,600-6,000 BC – creating extreme dry winter conditions. Unfortunately we don’t know how to reliably measure the impact of climate change on prehistoric societies, so interpretation is conjectural. Climate-induced migrations could potentially explain why farming spread as it did in the Balkans, reaching the Hungarian plain around 6,200 BC, and indeed spreading east and north towards the Dnieper catchment area north of the Black Sea. Similar dispersals are projected to have taken place across the Caucasus towards Russia, though the chronology is not as precise yet.

One hypothesis that I personally like – although I cannot assess how accurate it is – is that farming started to expand opportunistically beyond the Anatolian Plateau in the Aegean region, c. 6,600 BC, when this region became more attuned with the sort of environmental conditions observed in the Middle East – so that no major adaptation of crops and farming systems was needed for farming to expand.

7- Does the Neolithic transition indicate any increase in organised violence / weapons or can we safely say that discord between migrating people came much later?

There is evidence for large-scale interpersonal violence from the start of the Neolithic at Herxheim, in Western Germany, where the highly fragmented remains of over 300 individuals were found deposited in two concentric ditches. The focus was on heads and some of the skull caps found at the site bear cut marks that indicate removal of the scalp.

In Anatolia the picture is more contrasted, but there is no reason to assume that the Neolithic was any more peaceful. In addition to big obsidian arrowheads and spearheads at Çatalhöyük, a large number of later Neolithic sites show repeated evidence of fire destruction. In my PhD I have argued that intentional burning was part of normal house closure activities; houses were purposely infilled when abandoned and unusual series of objects, including blank arrowheads, were discarded on the last floor surfaces.

We don’t know how early farmers interacted with foragers in Anatolia; the Danube Gorges Mesolithic-Neolithic transition shows some interaction between farmers and foragers, though we don’t know if farmers were simply married into forager communities or brought there against their will. It is unlikely that early farming communities were very tolerant places, given that the Anatolian genetic signature remained mostly unchanged from Anatolia to Central Europe, suggesting that any admixture with hunter-gatherers remained off route and marginal. But until we know how many early farmers migrated out of Anatolia/the Aegean Basin, and how many hunter-gatherers they encountered along the way, we cannot really tell how often they met.

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