Corded Ware Culture (CWC) Genetics

Firstly, aDNA papers often stem from a limited number of samples, from which any pattern is then generalized across the entire geographical and temporal extent of the corresponding archaeological culture. The nature of aDNA data partly overcomes this problem (Li & Durbin, 2011) and further—hopefully more systematic—sampling will by definition improve the resolution. However, the limitations of this approach are obvious as the narrow range of samples does not allow one to explore possible differences within the geographical and temporal lapse of a given archaeological culture. Secondly, the question of relatedness between populations is central to the genetic entreprise, and reflected in ADMIXTURE and PCA graphs which provide statistically-informed depictions of this measure. The reasons for this preference lie deeply in the project of describing and understanding the variation of the modern Europe genetic variation. The difficulty lies when one attempts to translate biological relatedness in social terms, materialized by archaeological artefacts. This tension is well exemplified when genetic relations between central and eastern European third millennium bc samples are linked to corresponding material affinities between the Yamnaya and Corded Ware complexes while, as Furholt elegantly reminds us, the latter is pretty much typologically-related to all archaeological cultures before, after, and around it.

The above remarks arguably stem from a genuine lack of archaeological sophistication in most aDNA papers, in many ways repeating and prolonging the mistakes made by archaeologists for several decades. Are we thus in a theoretical impasse? Or is it that aDNA can only provide information with which we cannot do much? Most surely not. The bulk of the work has, so far, been carried out in a deceptively empirical way, taking advantage of a so-called golden phase where each sample is bound to tell us something that we by definition did not know about the genetic make-up of past populations. This strategy, while efficient in the short term, is hardly sustainable. The only viable alternative lies in complex hypotheses, informed and tested by several categories of evidence, all considered on equal footings.

Population history, including migration, provides a robust framework for such hypotheses to be elaborated. Indeed, the main result gained from aDNA, as well as from other studies, is that Neolithic populations were in constant flux, as suggested by ever-changing levels of admixture. This simple observation opens countless possibilities for future research. For instance, reading the literature, one can be left with the impression that the Early and Late Neolithic migration events were interchangeable, while they obviously happened under different demographic regimes, under different logistics, that is, in fundamentally different ways. Were small or large groups moving? Did the migration involve all categories of people, or were they sex-biased? Both questions can partly be answered by bioinformatic treatments of the data (e.g. Pemberton et al., 2012; Goldberg et al., 2017). Further fine-grained structure in these migrations will, without doubt, be unravelled by re-examining in parallel the aDNA and wider archaeological records. However, when doing so, and as hinted at by Furholt, we need to drive away from our implicit will to align neatly all signals to write simple, elegant, yet inherently faulty narratives. Genes and material culture, in their own complexity, do not operate in the same spheres of action, nor do they unfold upon the same spatial and temporal scales. We need to take advantage of their respective complexity to test alternative hypotheses, and get towards a more textured representation of the past.

To conclude, aDNA is, without any doubt, a fantastic technique, whose amazing potential we only begin to grasp. It is, however, worth remembering that this potential only applies to a narrow part of the archaeological agenda (e.g. Kintigh et al., 2014) and will only be unfolded by testing proper hypotheses, rather than chasing ghosts of our discipline's past. Of all social sciences, archaeology has assuredly the best track record at inter-disciplinarity and, thus, at overcoming a range of responses from extreme confidence to total disenchantment with new techniques. In this sense, the difficulties we encounter with aDNA are hardly new. Let us just not forget that any improvement will not simply come from ‘us’ teaching ‘them’, but also from us giving a hard look at ourselves in the mirror.

Genetic ancestry changes in Stone to Bronze Age transition in the East European plain


Transition from the Stone to the Bronze Age in Central and Western Europe was a period of major population movements originating from the Ponto-Caspian Steppe. Here, we report new genome-wide sequence data from 28 individuals from the territory north of this source area – from the under-studied Western part of present-day Russia, including Stone Age hunter-gatherers (10,800–4,250 cal BC) and Bronze Age farmers from the Corded Ware complex called Fatyanovo Culture (2,900–2,050 cal BC). We show that Eastern hunter-gatherer ancestry was present in Northwestern Russia already from around 10,000 BC. Furthermore, we see a clear change in ancestry with the arrival of farming – the Fatyanovo Culture individuals were genetically similar to other Corded Ware cultures, carrying a mixture of Steppe and European early farmer ancestry and thus likely originating from a fast migration towards the northeast from somewhere in the vicinity of modern-day Ukraine, which is the closest area where these ancestries coexisted from around 3,000 BC.

Introduction
The western part of the present territory of Russia has been a focal point of several prehistoric processes yet remains heavily under-represented in ancient DNA (aDNA) studies. Some of the oldest genetically studied individuals from Europe come from this region1–3, but overall, ancient genetic information is sparse.

The colonization of the Eastern and Northern European forest belt took place in two large waves during the end of the Paleolithic and the beginning of the Mesolithic period (bordering ca 9,700 cal BC). In both cases, groups of peoples with similar material cultures to those spread in wide areas of Europe took part in the colonization process. In regard to the Mesolithic settlements in the area, a number of distinct archaeological cultures (Butovo, Kunda, Veretye, Suomusjärvi etc.) have been identified4–7. In older stages of habitation, the material culture is so similar that it has also been handled as a single cultural area. However, from the middle of the 9th millennium cal BC, local population groups with clearly distinguished cultural differences already existed in the area8. Despite a series of small changes occurring during the Mesolithic period (as well as the Early Neolithic period according to the Russian periodization based on pottery production), the cultural continuities as a general trend of those groups are observable across time until the beginning of the 5th millennium, in some areas up to the beginning of the 4th millennium cal BC, when the so-called Pit-Comb Ware and Comb Ware cultures formed in wide areas of Europe9. In the territory of the Volga-Oka interfluvial area in Russia, Lyalovo Culture with pit-comb pottery and its local variants were described10. It is likely that the people from this cultural realm gave the starting boost to a series of developments in archaeological cultures specific to the 4th to 3rd millenniums cal BC, in particular to the Volosovo Culture, distinguishable in large areas of Russia11.

Genetic studies have shown that the Yamnaya Culture people spread out of the Steppe region of the Eastern European Plain and contributed significantly to the ancestry of the European populations12–14 that started to produce Corded Ware around 2,900–2,800 cal BC15. Furthermore, the migration of the Yamnaya population was two times faster than the Anatolian early farmer (EF) migration into Europe a few thousand years earlier and coincided with a decrease in broad-leaf forests and increase in grasslands/pastures in Western Europe16. The Corded Ware Culture (CWC) was spread on a wide area, reaching Tatarstan in the East, the southern parts of Finland, Sweden and Norway in the North, Belgium and Netherlands in the West, and Switzerland and Ukraine in the South17–19. Its easternmost extension – Fatyanovo Culture – is a prominent Eastern European CWC branch, that was spread over a large area in European Russia and introduced animal husbandry and probably crop cultivation into the forest belt20,21. So far, only 14 radiocarbon dates have been published for Fatyanovo Culture, placing it to 2,750–2,500 (2,300) cal BC21. The burial customs characteristic of the culture included the placement of the dead in flat earth graves (less often in barrows), mostly flexed and on their side – men mostly on the right and women on the left side – and shaft-hole stone axes, flint tools and ceramic vessels etc. as grave goods20,22.

European Mesolithic hunter-gatherers (HG) can be divided into groups based on their ancestry. The so-called Western group (WHG) was spread from Iberia to the Balkans and reached as far as the Late Mesolithic Eastern Baltic23–28. The Eastern group (EHG) had genetic influences from further east (a genetic connection to modern Siberians) and so far includes 6 individuals from Western Russia14,29,28,30. The genomes of four of these individuals have been previously studied from Karelia in the northwest from 7,500–5,000 BC14,28,29 and two from the Samara region in the eastern part of European Russia from 9,400–5,500 BC14,30.

The Yamnaya Culture pastoralists shared ancestry with EHG and Caucasus hunter-gatherers (CHG)31. Genetic studies have revealed that CWC individuals, with predominantly Yamnaya ancestry, showed some admixture with European EF of Anatolian ancestry and were most similar to modern populations from Eastern and Northern Europe13,14,29,32,28. Lactase persistence, frequent in contemporary Central and Northern Europe, was still at low frequency in the CWC individuals13,28,29,33 but underwent strong selection soon after28,33,34. It has also been shown that the Yamnaya expansion was male-biased35, while the Anatolian EF ancestry in the CWC individuals was acquired more through the female lineage32.

In this study, we aim to shed light on the demographic processes accompanying the change from a hunting-gathering lifestyle to crop cultivation and animal husbandry in the forest belt of Northeast Europe and to look into the genetic changes involved in the transition from the Stone to the Bronze Age in the western part of present-day Russia. We add almost 30 new radiocarbon dates from Western Russia and characterize the genetic affinities of the HG and Fatyanovo Culture farmers. As part of the study, we set out to examine if and how the major population movements seen in other parts of Europe during the Holocene have affected this area. Additionally, our aim is to shed light on local processes like the potential admixture between Volosovo and Fatyanovo Culture people suggested by archaeologists6,17,36.