Mitogenomes suggest rapid expansion of domesticated horse before 3500 BC

Open access Origin and spread of Thoroughbred racehorses inferred from complete mitochondrial genome sequences: Phylogenomic and Bayesian coalescent perspectives, by Yoon et al. PLOS One (2018).

Abstract (emphasis mine)

The Thoroughbred horse breed was developed primarily for racing, and has a significant contribution to the qualitative improvement of many other horse breeds. Despite the importance of Thoroughbred racehorses in historical, cultural, and economical viewpoints, there was no temporal and spatial dynamics of them using the mitogenome sequences. To explore this topic, the complete mitochondrial genome sequences of 14 Thoroughbreds and two Przewalski’s horses were determined. These sequences were analyzed together along with 151 previously published horse mitochondrial genomes from a range of breeds across the globe using a Bayesian coalescent approach as well as Bayesian inference and maximum likelihood methods. The racing horses were revealed to have multiple maternal origins and to be closely related to horses from one Asian, two Middle Eastern, and five European breeds. Thoroughbred horse breed was not directly related to the Przewalski’s horse which has been regarded as the closest taxon to the all domestic horses and the only true wild horse species left in the world. Our phylogenomic analyses also supported that there was no apparent correlation between geographic origin or breed and the evolution of global horses. The most recent common ancestor of the Thoroughbreds lived approximately 8,100–111,500 years ago, which was significantly younger than the most recent common ancestor of modern horses (0.7286 My). Bayesian skyline plot revealed that the population expansion of modern horses, including Thoroughbreds, occurred approximately 5,500–11,000 years ago, which coincide with the start of domestication. This is the first phylogenomic study on the Thoroughbred racehorse in association with its spatio-temporal dynamics. The database and genetic history information of Thoroughbred mitogenomes obtained from the present study provide useful information for future horse improvement projects, as well as for the study of horse genomics, conservation, and in association with its geographical distribution.

horse-domestication
Bayesian skyline plot (BSP) based on mitochondrial genome sequences from 167 modern horses.
The dark line in the BSP represents the estimated effective population size through time. The green area represents the 95% highest posterior density confidence intervals for this estimate.

Interesting excerpts:

We carried out a Bayesian coalescent approach using extended mitochondrial genome sequences from 167 horses in order to further assess the timescale of horse domestication. Here, we first calculated the time of the most recent common ancestor of Thoroughbred horses. Our analysis revealed the age of the most recent common ancestor of the racing horse to be around 8,100–111,500 years old. This estimate is much younger than that of the most recent common ancestor of the global horses, which has been estimated at 0.7286 Mys old.

phylogenetic-tree-horses
Bayesian maximum clade credibility phylogenomic tree on the ground of the mitochondrial genome sequences of 167 modern horses.
The data set (16,432 base pairs) was also analyzed phylogenetically using Bayesian inference (BI) and maximum likelihood (ML) methods which showed the same topologies. 95% Highest Posterior Density of node heights are shown by blue bars. Groups are marked by a “G”. Numbers at the nodes represent (left to right): posterior probabilities (≥0.80) for the BI tree and bootstrap values (≥70%) for the ML tree. The racing horses were revealed to have multiple maternal origins and to be closely related to horses from one Asian, two Middle Eastern, and five European breeds. Results of phylogenomic analyses also uncovered no apparent association between geographic origin or breed and heterogeneity of global horses. The most recent common ancestor of the Thoroughbreds lived approximately 8,100–111,500 years ago, which was significantly younger than the most recent common ancestor of modern horses (0.7286 My).

On the domestication time of modern horses, there have been several publications derived from both archaeological [49–51] and molecular [11–12, 23, 48] evidences. D’Andrade [49] reported that the origin of domestic horses was around 4,000 years ago. Ludwig et al. [50] stated the domestication time to be about 5,000 years ago, while Anthony [51] noted that horse rearing by humans may have occurred approximately 6,000 years ago. Subsequently, on the basis of mitochondrial genome sequences, Lippold et al. [11] and Achilli et al. [12] postulated domestication time to be about 6,000–8,000 and 6,000–7,000 years ago, respectively. Warmuth [48] dated domestication time to 5,500 years ago based on autosomal genotype data, while Orlando et al. [23] claimed that Przewalski’s and domestic horse populations diverged 38,000–72,000 years ago based on analysis of genome sequences. In contrast to the previous hypothesized date of horse domestication, the results of our Bayesian skyline plot (BSP) analysis depict a rapid expansion of the horse population approximately 5,500–11,000 years ago, which coincides with the start of domestication.

It seems that we will not have an update on horse aDNA from the ISBA 8, so we will have to make do with this for the moment.

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Modelling of prehistoric dispersal of rice varieties in India point to a north-western origin

rice-dispersal

New paper (behind paywall), A tale of two rice varieties: Modelling the prehistoric dispersals of japonica and proto-indica rices, by Silva et al., The Holocene (2018).

Interesting excerpts (emphasis mine):

Materials

Our empirical evidence comes from the Rice Archaeological Database (RAD). The first version of this database was used for a synthesis of rice dispersal by Fuller et al. (2010), a slightly expanded dataset (version 1.1) was used to model the dispersal of rice, land area under wet rice cultivation and associated methane emissions from 5000–1000 BP (Fuller et al., 2011). The present dataset (version 2) was used in a previous analysis of the origins of rice domestication (Silva et al., 2015). The database records sites and chronological phases within sites where rice has been reported, including whether rice was identified from plant macroremains, phytoliths or impressions in ceramics. Ages are recorded as the start and end date of each phase, and a median age of the phase is then used for analysis. Dating is based on radiocarbon evidence (…)

Modelling framework

Our approach expands on previous efforts to model the geographical origins, and subsequent spread, of japonica rice (Silva et al., 2015). The methodology is based on the explicit modelling of dispersal hypotheses using the Fast Marching algorithm, which computes the cost-distance of an expanding front at each point of a discrete lattice or raster from the source(s) of diffusion (Sethian, 1996; Silva and Steele, 2012, 2014). Sites in the RAD database are then queried for their cost-distance, the distance from the source(s) of dispersal along the cost-surface that represents the hypothesis being modelled (see Connolly and Lake, 2006; Douglas, 1994; Silva et al., 2015; Silva and Steele, 2014 for more on this approach) and, together with the site’s dating, used for regression analysis. (…)

india-japonica-rice
Predicted arrival times of the non-shattering rice variety (japonica or the hybrid indica) across southern Asia based on best-fitting model H2. Included are also sites with known presence of non-shattering spikelet bases (see text).

Model and results

The ‘Inner Asia Mountain Corridor’ hypothesis (H2) therefore predicts japonica rice to arrive first in northwest India via a route that starts in the Yellow river valley, travels west via the well-known Hexi corridor, then just south of the Inner Asian Mountains and thence to India.

The results also show that the addition of the Inner Asia Mountain Corridor significantly improves the model’s fit to the data, particularly model H2 where rice is introduced to the Indian subcontinent exclusively via a trade route that circumvents the Tibetan plateau. This agrees with independent archaeological evidence that sees millets spread westwards along this corridor perhaps as early as 3000 BC (e.g. Boivin et al., 2012; Kohler-Schneider and Canepelle, 2009; Rassamakin, 1999) and certainly by 2500–2000 BC (Frachetti et al., 2010; Spengler 2015; Stevens et al., 2016), that is, in the same time frame as that predicted for rice in model H2. The arrival of western livestock (sheep, cattle) into central China, 2500–2000 BC (Fuller et al., 2011; Yuan and Campbell, 2009), and wheat, ca. 2000 BC (Betts et al., 2014; Flad et al., 2010; Stevens et al., 2016; Zhao, 2015), add evidence for the role of the Inner Asia Mountain Corridor for domesticated species dispersal in this period.

Conclusion

Through a combination of explicit spatial modelling and simulation, we have demonstrated the high likelihood that dispersal of rice via traders in Central Asia introduced japonica rice into South Asia. Only slightly less likely is a combination of introduction via two routes including a Central Asia to Pakistan/northwestern India route as well as introduction to northeastern India directly from China/Myanmar. However, there is a very low probability that current archaeological evidence for rice fits with a single introduction of japonica into India via the northeast. We have also simulated the minimum amount of archaeobotanical sampling from the Neolithic (to Bronze Age) period in the regions of northeastern India and Myanmar that will be necessary to strengthen support for the combined introduction (model H3) or a single Central Asian introduction (model H2).

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Earliest evidence for equid riding in the ancient Near East is a donkey from the Early Bronze Age

Open access Earliest evidence for equid bit wear in the ancient Near East: The “ass” from Early Bronze Age Tell eṣ-Ṣâfi/Gath, Israel, by Greenfield et al. PLOS One

Abstract:

Analysis of a sacrificed and interred domestic donkey from an Early Bronze Age (EB) IIIB (c. 2800–2600 BCE) domestic residential neighborhood at Tell eṣ-Ṣâfi/Gath, Israel, indicate the presence of bit wear on the Lower Premolar 2 (LPM2). This is the earliest evidence for the use of a bit among early domestic equids, and in particular donkeys, in the Near East. The mesial enamel surfaces on both the right and left LPM2 of the particular donkey in question are slightly worn in a fashion that suggests that a dental bit (metal, bone, wood, etc.) was used to control the animal. Given the secure chronological context of the burial (beneath the floor of an EB IIIB house), it is suggested that this animal provides the earliest evidence for the use of a bit on an early domestic equid from the Near East.

Interesting excerpts:

In contrast to what is known about the use of donkeys for transportation, relatively little is known about their use for riding during this early period [37]. Riding is possible, but fast riding is difficult without some kind of bridle with reins to grasp. Thus, the development of the bit becomes an essential part of the mechanism to control and ride an equid, whether horse, donkey or otherwise [38–41]. While some have tried to argue based on cave art for the presence of bridles (including cheek straps and potentially bits) on equids as far back as the Upper Palaeolithic [42, 43], this perspective has not been accepted [44, 45]. Instead, the weight of the evidence for bridles points toward the Eneolithic and Bronze Age of Kazakhstan and Russia, c. 3500 BCE for horses, not donkeys [38, 40, 46–50]. But, horses are not the earliest domestic equids to appear in the Near East. This role is reserved for the ass/donkey [20, 32, 51].

donkey-middle-east
Photograph of donkey burial from the E5c Stratum of Area E at Tell eṣ-Ṣâfi/Gath in Area E as it was being uncovered; facing north.

The earliest unambiguous evidence for bridles and bits in equids in the Near East appear only in the Middle Bronze Age [52, 62, 63], and horses become common only in cuneiform texts and the archaeological record after the turn of the second millennium BC [44]. For example, at the Middle Bronze Age site of Tel Haror, a metal bit was found associated with a donkey burial [63].

Beginning in the Middle Bronze Age, there is a variety of sources that demonstrate that asses were being ridden. In fact, they seem to be the preferred animal ridden for elites in the Early and Middle Bronze Age of Mesopotamia. The earliest clear association of asses being ridden by elites comes from the Old Babylonian period (MBA, 18th century BCE—the Kings of Mari, Syria) [64]. Similarly, by the beginning of the Middle Kingdom of Egypt, various texts and iconographic images (e.g. the stela of Serabit el-Khadem) from Egypt and petroglyphs from southern Sinai unambiguously depict and/or describe elites riding asses [5, 65, 66]. The later biblical narrative depicts donkeys carrying the biblical Patriarchs (Abraham), various leaders (such as Saul before he became king), prophets, and judges of Israel [16, 67, 68].

Horses became the standard royal riding animal during the Late Bronze and Iron Ages as they became more prevalent. In later periods, donkeys became associated with humility and the lower classes, and leaders emanating from it (e.g. Jesus).

These finds suggest that bit use on donkeys was already present in the early to mid-3rd millennium BCE, long before the appearance of horses in the ancient Near East. Thus, the appearance of bit use in donkeys in the ancient Near East is not connected to appearance of the horse, contrary to previous suggestions (as already noted by [62]). As such, the impact of the domestic donkey on the cultures of this region and the evolution of early complex societies cannot be underestimated. As with plant and animal domestication, the use of donkeys created a surplus of human labor that allowed for the easy transport of people and goods across the entire Near East. These changes continue to permeate the economic, social, and political aspects of even modern life in many third world countries [3, 8, 9, 93, 94].

So, the first case of equid riding in the Near East, near two of the cradles of civilization (Sumeria and Egypt), is a donkey from the early third millennium BC. Not much in favour of horse domestication (and still less for horse riding) expanding from Norh Iran or the Southern Caucasus to the north.

We already know about domesticated animals in Eneolithic steppe cultures, and there is a clear connection between the appearance of horse riding in Khvalynsk in the early 5th millennium and the expansion of this culture, including Suvorovo-Novodanilovka chiefs as Proto-Anatolians via the Balkans in the second half of the 5th millennium BC, and of Late Proto-Indo-Europeans with late Khvalynsk/Yamna in the late 4th millennium BC.

NOTE. The recent papers of the Copenhagen group made yet another controversial interpretation of genomic findings (see here): they support multiple simultaneous origins for horse-riding technique, in Khvalynsk and Botai, based on the lack of genetic connection between both human populations, with which I can’t agree. Based on the similar time of appearance and the geographic proximity, I think the most likely explanation is expansion of the technique from one to the other, probably – as supported by Anthony’s investigation – from Khvalynsk to neighbouring cultures.

Related:

Domestication spread probably via the North Pontic steppe to Khvalynsk… but not horse riding

Interesting paper Excavation at the Razdolnoe site on the Kalmius river in 2010, by N. Kotova, D. Anthony, D. Brown, S. Degermendzhy, P. Crabtree, In: Archaeology and Palaeoecology of the Ukrainian Steppe / IA NAS of Ukraine, Kyiv 2017.

Nothing new probably to those who have read Anthony (2007), but this new publication of his research on the North Pontic region seems to contradict recent papers which cast doubts on the presence of early forms of domestication in the North Pontic steppe, and would reject thus also the arrival of domestication to Khvalynsk from a southern route.

Interesting excerpts discussing recent research and results of this one (emphasis mine):

A brief comment about the fauna is required. A separate international archaeological project studied sites dated to the mid — 6th millennium BC in the Severskiy Donets basin (Starobelsk I, Novoselovka III) northeast of Razdolnoe, and found that they had hunting and gathering economies that made use of Unio shellfish, fish, and turtles, like the Neolithic occupation at Razdolnoe. But the Donets sites had no domesticated animal species. The author argued that the cultures of the Donets and lower Don basins in the 6th millennium BC probably had no domesticated animals, and that the domesticated sheep-goat bones identified at Semenovka, west of Razdolnoe, and dated to 5500 calBC, probably were mis-identified and actually came from wild saiga antelope (Motuzaite- Matuzeviciute 2012: 14). This suggestion was made on the basis of a single bone identified as sheep-goat at Semenovka by O.P. Zhuravlev (not N.S. Kotova as Motuzaite-Matuzeviciute wrote) and sent out for radiocarbon dating, that was re-examined by Cambridge University archaeozoologists.

Regardless of which identification is correct, a single bone is insufficient to cast doubt on sheep-goat bones identified at Sredni Stog 1, Sobachki, and other Neolithic sites in the Dnieper valley. Nevertheless, yet another international collaboration that studied the economy of Dereivka in the Dnieper valley argued that the economy of Eneolithic Dereivka site, which they dated to about 3500 calBC (ignoring 10 radiocarbon dates between 4200—3700 calBC), was still at an «initial phase of animal domestication» and that the Dereivka occupants of 3500 calBC were still largely dependent on hunting and fishing (Mileto et al. 2017: 67—68).

The dated Bos calf in the lower occupation level at Razdolnoe shows that domesticated animals were present in the Kalmius river valley in the Azov steppes in 5500 calBC, at a time when the cultures of the Donets valley were still hunters and gatherers just 200 km to the northeast of Razdolnoe. Sheep-goat and Bos bones were found in all Neolithic and Eneolithic levels at Razdolnoe. Because it was a small excavation, this evidence should not be over-interpreted. We cannot say how important domesticated animals were in the daily diet. But domesticated sheep-goat and cows had reached the Azov steppes by 5500 calBC. The appearance of cattle and sheep-goat as sacrificial animals in graves of the Khvalynsk Culture on the Volga by the early 5th millennium BC probably was a continuation of the spread of animal herding eastward from the Azov steppes.

neolithic_steppe-anatolian-migrations
Most likely route of expansion of horse domestication and horse riding (including Suvorovo-Novodanilovka chiefs) from Khvalynsk into the North Pontic steppe and the Balkans.

Re-reading the papers on this subject – in which researchers seem to be fighting among each other for a radical interpretation of few animal bones – , I would suggest that the key concept they should be emphasizing is probably not the ‘presence’ vs. ‘absence’ of domestication in North Pontic steppe cultures in absolute terms.

Since there were clearly domesticated animals to the east and west of North Pontic cultures in the Neolithic, and thus the finding there of domesticated animals is more than likely, what is of great interest is the relative measure in which domesticated animals were relied upon by forest-steppe economies, compared to the use of available natural resources.

After all, many researchers currently agree that the North Pontic steppe and forest-steppe peoples formed communities of mainly hunter-fishers and gatherers, and findings of this paper do not seem to contradict this.

NOTE. In fact, there was a more recent paper I referenced which argues in such general terms with detail – probably written at the same time as this one -, by one of the authors they discuss, Mileto et al. (2018).

Also, as the paper states,

we want to emphasize that even a small excavation in the steppe zone, where only scanty number of the Neolithic and Eneolithic sites have been known yet, is very important and always gives very interesting materials.

Hence by confirming Anthony’s account of early domestication spreading eastwards during the Neolithic expansion, and without horses’ remains in any of the periods investigated (including Sredni Stog I-III), it also supports his hypothesis of horse riding emerging in Khvalynsk and expanding westward.

The Razdolnoe site lies near modern-day Donetsk, and its latest layer investigated (ca. 4300-4150 BC) represents thus the eastern variant of Sredni Stog III, being consequently the one more in contact with expanding early Khvalynsk.

Given the absence of horse remains in all layers, these results would also suggest that Novodanilovka and Suvorovo horse-riding chiefs (emerging ca. 4400-4200 BC to the west of this region) were indeed unrelated to the surrounding Sredni Stog population, and most likely migrants from the horse-riding Khvalynsk culture.

Featured image: Expansion of domestication in the Pontic-Caspian steppe, according to Anthony (2007).

Related:

Decline of genetic diversity in ancient domestic stallions in Europe

Open access research article Decline of genetic diversity in ancient domestic stallions in Europe, by Wutke et al., Science (2018), 4(4):eaap9691.

Abstract (emphasis mine):

Present-day domestic horses are immensely diverse in their maternally inherited mitochondrial DNA, yet they show very little variation on their paternally inherited Y chromosome. Although it has recently been shown that Y chromosomal diversity in domestic horses was higher at least until the Iron Age, when and why this diversity disappeared remain controversial questions. We genotyped 16 recently discovered Y chromosomal single-nucleotide polymorphisms in 96 ancient Eurasian stallions spanning the early domestication stages (Copper and Bronze Age) to the Middle Ages. Using this Y chromosomal time series, which covers nearly the entire history of horse domestication, we reveal how Y chromosomal diversity changed over time. Our results also show that the lack of multiple stallion lineages in the extant domestic population is caused by neither a founder effect nor random demographic effects but instead is the result of artificial selection—initially during the Iron Age by nomadic people from the Eurasian steppes and later during the Roman period. Moreover, the modern domestic haplotype probably derived from another, already advantageous, haplotype, most likely after the beginning of the domestication. In line with recent findings indicating that the Przewalski and domestic horse lineages remained connected by gene flow after they diverged about 45,000 years ago, we present evidence for Y chromosomal introgression of Przewalski horses into the gene pool of European domestic horses at least until medieval times.

horses-y-chromosome-evolution
The frequencies of Y chromosome haplotypes started to change during the Late Bronze Age (1600–900 BCE).
Inferred temporal trajectories of haplotype frequencies. Each haplotype is displayed by a different color. The shaded area represents the 95% highest-density region. The trajectories were constructed taking the median values across frequencies from the simulations of the Bayesian posterior sample. The small chart represents the stacked frequencies; the amplitude of each colored area is proportional to the median haplotype frequencies (normalized) at a given time. The x and y axes of the small chart match those in the large one. Ka, thousands of years.

Interesting excerpts:

The first record of the modern domestic Y chromosome haplotype stems from two Bronze Age samples of similar age. Notably, both samples were found in two distantly located regions: present-day Slovakia (2000–1600 BCE, dated by archaeological context) and western Siberia (14C-dated: 1609–1436 cal. BCE). Although a very recent study proposes an oriental origin of this haplotype (14), we cannot determine the geographical origin of Y-HT-1 with certainty, because this haplotype has not been found thus far in predomestic or wild stallions. There are two possible scenarios: (i) Y-HT-1 emerged within the domestic population by mutation and (ii) Y-HT-1 was already present in wild horses and entered the domestic population either at the beginning of domestication (but initially restricted to Asian horses) or later by introgression (from wild Y-HT-1 carrying studs during the Iron Age). Crosses between domestic animals and their wild counterparts have been observed in several domestic species (15–18); thus, the simplest explanation would be that we missed Y-HT-1 in older samples because of limited geographical sampling. However, the estimated haplotype age is contemporary (Fig. 4) with the assumed starting point of horse domestication ~4000–3500 BCE (19), rendering it likely that Y-HT-1 originated within the domestic horse gene pool. Still, we cannot rule out definitively that it appeared before domestication.

Independent of its geographical origin, Y-HT-1 progressively replaced all other haplotypes—except for one additional lineage that is restricted to Yakutian horses (11). Considering our data, this trend in paternal diversity toward dominance of the modern lineage appears to start in the Bronze Age and becomes even more pronounced during the Iron Age. The Bronze Age was a time of large-scale human migrations across Eurasia (20–22), movements that were undoubtedly facilitated by the spread of horses as a means of transport and warfare. At that time, the western Eurasian steppes were inhabited by highly mobile cultures that largely relied on horses (20, 21, 23, 24). The genetic admixture of northern and central European humans with Caucasians/eastern Europeans did correlate with the spread of the Yamnaya culture from the Pontic-Caspian steppe (25), an area that has repeatedly been suggested as the center of horse domestication (19, 26, 27). Given the importance of domestic horses, it appears that deliberate selection/rejection of certain stallions by these people might have contributed to the loss of paternal diversity. The spread of humans out of this region might also have resulted in the spread of Y-HT-1 from Asia to Europe. This scenario also agrees with recent findings that the low male diversity of extant horses is not caused by recruiting only a limited number of stallions during early domestication (13).

horses-y-chromosome-map
Decline of paternal diversity began in Asia.
Maps displaying age, locality, and haplotype (different colors) of each successfully genotyped sample.

The presence of the Y chromosome haplotype carried by present-day Przewalski horses (Y-HT-2) in early domestic stallions and a European wild horse (Pie05; table S2) could be the result of introgression of Przewalski stallions. Although the original distribution of the Przewalski horse is unknown, it was probably much larger than that of the relict population in Mongolia that produced modern Przewalski horses and might even have extended into Central Europe. However, it is also possible that either Przewalski horses were among the initially domesticated horses or that Y-HT-2 occurred both in Przewalski horses and in those wild horses that are the ancestors of domestic horses, based on autosomal DNA data (30). Regardless of how Y-HT-2 entered the domestic gene pool, it was eventually lost, as were all haplotypes except Y-HT-1. In our sample set, Y-HT-2 was undetectable as early as the third time bin. However, it is possible that Y-HT-2 may have been present during this time period, but with a frequency below 0.11 (with 95% probability). The inferred time trajectories for Y-HT-2 frequencies suggest that it could nevertheless have persisted at very low frequencies until the Middle Ages (Fig. 3). On the basis of these simulations, this finding could be interpreted as a relic of this haplotype’s formerly higher frequency in the domestic horse gene pool. It is also possible that the presence of this haplotype could be the result of mating a wild stallion with a domestic mare, a frequently reported breeding practice when wild horses were still widely distributed. However, a significant contribution of the Przewalski horse to the gene pool of modern domestic horses has been almost ruled out by recent genomic studies (13, 31, 32).

horses-y-chromosome-selection
Stallion lineages through time.
Temporal haplotype network of the four detected Y chromosome haplotypes. Age of the samples indicated by multiple layers separated by color; vertical lines connecting the haplotypes of consecutive layers/ages represent which haplotype was transferred into a later/younger period. Numbers constitute the respective number of individuals showing this particular haplotype for that period. Prz, Przewalski; Dom, domestic.

Related:

Agricultural origins on the Anatolian plateau

anatolia-neolithic-agriculture

New paper (behind paywall) Agricultural origins on the Anatolian plateau, by Baird et al. PNAS (2018), published ahead of print (March 19).

Abstract (emphasis mine):

This paper explores the explanations for, and consequences of, the early appearance of food production outside the Fertile Crescent of Southwest Asia, where it originated in the 10th/9th millennia cal BC. We present evidence that cultivation appeared in Central Anatolia through adoption by indigenous foragers in the mid ninth millennium cal BC, but also demonstrate that uptake was not uniform, and that some communities chose to actively disregard cultivation. Adoption of cultivation was accompanied by experimentation with sheep/goat herding in a system of low-level food production that was integrated into foraging practices rather than used to replace them. Furthermore, rather than being a short-lived transitional state, low-level food production formed part of a subsistence strategy that lasted for several centuries, although its adoption had significant long-term social consequences for the adopting community at Boncuklu. Material continuities suggest that Boncuklu’s community was ancestral to that seen at the much larger settlement of Çatalhöyük East from 7100 cal BC, by which time a modest involvement with food production had been transformed into a major commitment to mixed farming, allowing the sustenance of a very large sedentary community. This evidence from Central Anatolia illustrates that polarized positions explaining the early spread of farming, opposing indigenous adoption to farmer colonization, are unsuited to understanding local sequences of subsistence and related social change. We go beyond identifying the mechanisms for the spread of farming by investigating the shorter- and longer-term implications of rejecting or adopting farming practices.

anatolia-neolithic
Map of central Anatolia showing the principal sites mentioned in the text.

Interesting excerpts:

The persistence of foraging and rejection of farming at Pınarbaşı is also worthy of further consideration. Pınarbaşı’s longevity as a settlement locale in the early Holocene appears to have been based on hunting of wild mammals, wetland exploitation, and significant focus on nut exploitation, all afforded by its ecotonal setting between the hills, plain, and wetland. Perhaps this existing diversity, including nutritious storable plant resources, was a key factor in a lack of interest in adopting cultivation. Another factor may have been a conscious desire to maintain traditional identities and long-standing distinctions with other communities, in part reflected in its particular way of life and its specific connections with particular elements in landscape, for example the almond and terebinth woodlands whose harvests underwrote the continuity of the Pınarbaşı settlement.

The variability in response to the possibilities of early food production in a relatively small geographical area demonstrated here is notable and provides an example useful in evaluating the spread of farming in other regions. It shows the possible role of indigenous foragers, the potential patchwork and diffuse nature of the spread of farming, the lack of homogeneity likely in the communities caught up in the process, the probability of significant continuities in local cultural traditions within the process, and the potentially long-term stable adaptation offered by lowlevel food production. The strength of identities linked to exploitation of particular foods and particular parts of the landscape may have been a major factor contributing to rejection or adoption of food production by indigenous foragers.

The results are also relevant for understanding the processes that underpinned the initial development of farming within the Fertile Crescent itself: that is, the region in which the wild progenitors of the Old World founder crops and stock animals are found. Recent research has rejected the notion of a core area for farming’s first appearance in southwest Asia and demonstrated that farming developed in diverse ways over the Fertile Crescent zone from the southern Levant to the Zagros, very analogous to the situation just described for Central Anatolia (2). Cultivation, herding, and domestication developed in that region, and it seems inescapable that exchange of crops and herded animals occurred between communities (2), involving a spread of farming within the Fertile Crescent, leading eventually to the Neolithic farming package that was so similar across the region and which spread into Europe (5). Central Anatolia was clearly linked to the Fertile Crescent, with significant evidence of exchange and some shared cultural traditions from at least the Epipaleolithic (22). The evidence presented here demonstrates very clearly the movement of crops between settlements and regions in early phases of the Neolithic through exchange, and thus allows us to identify episodes of crop exchange that were probably taking place within the Fertile Crescent itself, but are difficult, if not impossible, to distinguish due to the presence of crop progenitors across much of the region.

A very interesting read in combination with 14C-radiometric data and climatic conditions showing potential triggers of dispersal of Neolithic lifeways from Turkey to Southeast Europe, e.g. Dispersal of Neolithic Lifeways: Absolute Chronology and Rapid Climate Change in Central and West Anatolia, by Lee Clare & Bernhard Weninger, in The Neolithic in Turkey, Vol.6 (2014), Edited by Mehmet Özdogan, Nezih Basgelen, Peter Kuniholm.

anatolian-neolithic-aegean
The Late Neolithic (6600-6000 cal. BC) witnesses the rapid westward dispersal of Neolithic communities, apparently reaching the Aegean in the space of a very short time (ca. 6600 cal. BC). This process is linked to the demand of individuals, groups, and communities for less vulnerable conditions in the face of climate fluctuation associated with RCC. Coastal areas not only offered respite from more frequently occurring physical impacts (extreme winters and high drought risk) in inner Anatolia, they may also have provided refuge for weaker (more vulnerable) social groups (…).

Featured image, from the latter: “In the Early Pottery Neolithic (7000-6600 cal. BC) there occurs a clear break with precedeing (PPN) traditions, attested by abandonment and decreasing size of settlements, albeit that evidence for migration of groups westwards towards the Aegean is still ambiguous (black arrows: human migrations; white arrows: Anatolian obsidian)”

See also:

The concept of “Outlier” in Human Ancestry (III): Late Neolithic samples from the Baltic region and origins of the Corded Ware culture

corded-ware-regions-main

I have written before about how the Late Neolithic sample from Zvejnieki seemed to be an outlier among Corded Ware samples (read also the Admixture analysis section on the IEDDM), due to its position in PCA, even more than its admixture components or statistical comparison might show.

In the recent update to Northern European samples in Mittnik et al. (2018), an evaluation of events similar to the previous preprint (2017) is given:

Computing D-statistics for each individual of the form D(Baltic LN, Yamnaya; X, Mbuti), we find that the two individuals from the early phase of the LN (Plinkaigalis242 and Gyvakarai1, dating to ca. 3200–2600 calBCE) form a clade with Yamnaya (Supplementary Table 7), consistent with the absence of the farmer-associated component in ADMIXTURE (Fig. 2b). Younger individuals share more alleles with Anatolian and European farmers (Supplementary Table 7) as also observed in contemporaneous Central European CWC individuals2.

baltic-region-mittnik
Sampling locations and dating of 38 ancient Northern European samples introduced in this study. Chronology based on calibrated radiocarbon dates or relative dating

My interpretation of the Zvejnieki sample ca. 2880 BC (and thus also of the only Baltic LN sample forming a close cluster with it) as ‘outlier’ seems thus reinforced as more samples come in. My explanation based on exogamy is one possibility for the region. After all, great mobility and exogamy practices are universally accepted for the Corded Ware territory, and Yamna migrants had settled up along the Prut precisely around this period (ca. 3100-2900 BC), so this kind of relation between Yamna and Baltic samples is to be expected.

NOTE: Information on the Late Neolithic burial of Zvejnieki is scarce, since it is an isolated find in radiocarbon analysis, among Mesolithic burials. You can read more about it from Ilga Zagorska’s studies, such as The use of ochre in Stone Age burials of the East Baltic (2008), The persistent presence of the dead: recent excavations at the hunter-gatherer cemetery at Zvejnieki (Latvia) (Antiquity 2013), or Dietary freshwater reservoir effects and the radiocarbon ages of prehistoric human bones from Zvejnieki, Latvia (J. Archaeol. Sci. 2016).

Samples of Baltic “Late Neolithic / Corded Ware culture”

The only two samples clustering more closely to Yamna cluster also closely to the three previous samples from Khvalynsk in Samara (labelled ‘Steppe Eneolithic’ in the paper), which makes one wonder how strongly connected were cultures from the forest and forest-steppe zones before the expansion of Corded Ware and Yamna settlers.

NOTE: Apart from the scarcity of samples available, which is common in genetic studies, the description of both additional ‘outlier’ samples of the Baltic Late Neolithic – isolated finds based mainly on radiocarbon analysis – leaves a lot to the imagination, because of the lack of cultural context and potential problems with dating methods:

Plinkaigalis 242, >40 year old female (OxA-5936, 4280 ± 75 BP, 3260–2630 calBCE). The burial site is located in the plains of central Lithuania on the eastern bank of the river Šušvė on the outskirts of the Plinkaigalis village, approximately 400 m southeast of an Iron age hill fort and settlement. The burial site was discovered in 1975 when local residents started digging for gravel in the western part of the hill. The same year site was granted a legal protection with archaeological excavations carried out for eight straight years in a row (1977-1984). During the eight years of fieldwork a total of 373 graves (364 inhumation and 9 cremation graves) with all but two of them dating to 3rd to 8th c. AD were uncovered. The two exceptional graves (no. 241, 242) were uncovered in the northern part of the burial site and C14 dated to the Late Neolithic.

Gyvakarai 1, 35-40 year old male (Poz-61584, 4030 ± 30 BP, 2620–2470 calBCE). The burial site is located in the northern part of Lithuania on the steep gravelly bank (elevation up to 79 m a. s. l.) of the rivulet Žvikė, 500 m to the south from where, in the wet grassland valley, it meets the main stem river Pyvesa. The site was discovered in 2000 when local residents started digging for gravel in the central part of the gravelly bank. The same year rescue excavations were conducted in the surrounding area of the highly disturbed grave resulting in discovery of a single grave C14 dated to the Late Neolithic.

EDIT (16 FEB 2018): A commentator noted that Gyvakaray1 was also studied for Yersinia pestis, a disease which appears to have expanded first to the west from the steppe, and then to the east, so it is possible that its position in PCA related to Plinkaigalis242 shows a connection to late Yamna settlers or East Bell Beaker migrants.

pca-mittnik
File modified by me from Mittnik et al. (2018) to include the approximate position of the most common ancestral components, and an identification of potential outliers. Zoomed-in version of the European Late Neolithic and Bronze Age samples. “Principal components analysis of 1012 present-day West Eurasians (grey points, modern Baltic populations in dark grey) with 294 projected published ancient and 38 ancient North European samples introduced in this study (marked with a red outline).

NOTE: I haven’t had the time and patience to work with my virtual computer on the PCA of these new samples – my CPU is reaching everyday its limit and my fans work half the time – , so I don’t know exactly which of them is Plinkaigalis242 and which Gyvakarai1, I just made a wild guess (based on ADMIXTURE) that the earlier Plinkaigalis242 forms a common ‘outlier’ group with Zvejnieki; if they are reversed or otherwise wrong in the image, please correct me. It will be much appreciated.

We can see from the additional samples in Mittnik et al. (2018) that the common cluster formed by most Baltic LN samples in PCA (most of them with clear cultural context among Late Neolithic or Corded Ware material, unlike the two ‘outliers’ and Gyvakarai1) is among Ukraine Eneolithic samples, European Corded Ware samples, and also Mesolithic-Neolithic samples from the Baltic. This is a logical find in light of the mainstream opinion that the expansion of the third horizon of the Corded Ware culture seems to have begun in the Dnieper-Dniester region (a corridor of steppe, steppe-forest, and forest zones) ca. 3300 BC.

baltic-samples
PCA and ADMIXTURE analysis reflecting three time periods 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 38 ancient North European samples introduced in this study (marked with a red outline). Population labels of modern West Eurasians are given in Supplementary Fig. 7 and a zoomed-in version of the European Late Neolithic and Bronze Age samples is provided in Supplementary Fig. 8. b Ancestral components in ancient individuals estimated by ADMIXTURE (k = 11)

Corded Ware culture origins

If we take the most recent reliable radiocarbon analyses of material culture, and interpretations based on them of Corded Ware as a ‘complex’ similar to Bell Beaker (accepted more and more by disparate academics such as Anthony or Klejn), it seems that the controversial ‘massive’ Corded Ware migration must have begun somehow later than previously thought, which leaves these early Baltic samples still less clearly part of the initial Corded Ware culture, and more as outliers waiting for a more precise cultural context among Late Neolithic changes in the region.

Their situation in PCA among Khvalynsk (Samara), Baltic Mesolithic, East Hunger-Gatherer samples, Yamna and Eneolithic Ukraine leaves us without enough information to understand their actual origin.

EDIT (3 FEB 2018): In the first edition of my IEDDM paper I based the potential expansion of the Corded Ware culture mainly on Piezonka’s detailed analyses of the evolution of Mesolithic and Neolithic cultures in the forest-steppe and Forest Zone, and on later phylogeographic finds, since there were no samples from these regions in this interesting period. I revised it in the second edition to accomodate the model to the Indo-Uralic proto-language supported by the Leiden school, and identified it with a a close Neolithic-Chalcolithic steppe community based on common language guesstimates and – after the latest revision of Mathieson et al. (2017) – on the appearance of steppe admixture in the steppe.

However, if traditional Uralicists are right in supposing a loose Neolithic community in the Forest Zone, and Kristiansen is right in supposing long-lasting contacts in the Dniester-Dnieper region, we might actually be seeing with these ‘outliers’ the first proof that Neolithic samples from the forest-steppe and Forest Zone of the 4th millenium – unrelated to the Corded Ware culture – clustered closely to Khvalynsk, Sredni Stog, or Yamna samples, which is compatible with Piezonka’s accounts of intercultural contacts.

Martin Furholt‘s assessment of the origin of the A-horizon of the Corded Ware culture would put the early dates of Late Neolithic in the Baltic coinciding with or just before the initial expansion of Corded Ware migrants. For example, here are some excerpts (emphasis mine) from Re-evaluating Corded Ware Variability in Late Neolithic Europe (2014), in Proceedings of the Prehistoric Society (you can read it free at Academia.edu):

Radiocarbon analysis

Acceptance of the results of radiometric dating meant that the concept of the so called ‘A-Horizon’ also had to be reformulated. If we are dealing with such a phase at all, it is not a classic typological period that is defined by a uniform material culture inventory, but rather a set of types which show a wide distribution, but which are always integrated into a locally specific and thus regionally variable context.

The situation resembles that of the Bell Beakers, where a few supra-regional types are associated with local forms of ‘Begleitkeramik’ (i.e. pottery that accompanies Bell Beakers: Strahm 1995; Besse 1996).

The distribution data indicate that this set of forms (namely the A-Beaker, ‘A-Amphora’, and A-Battle Axe, as well as Herringbone-decorated Beakers) was to be found over much of Europe around 2700 BC, and that the currency of these forms was not short: they seem to have been used continuously during the Final Neolithic, perhaps even until 2000 BC (Fig. 3; Furholt 2004). Analysis of the radiometric and dendrochronological determinations also indicates that the A-Horizon is not the earliest Corded Ware phase. Instead, it appears to follow an apparent earlier phase in Poland during which Corded Ware pottery was in use from as early as 2900 BC (Furholt 2003; 2008a; Wödarczak 2006; Ullrich 2008).

corded-ware-chronology
Chronological model following from radiocarbon dating. Mark the contrast to the traditional model of the A-horizon as the earliest phase and a successive increase in regional variability later on

Corded Ware and Yamna/Bell Beaker

While widening networks and a change in the mechanism of exchange appears to have contributed to the emergence of the Corded Ware archaeological phenomenon, and also the contemporaneous Yamnaya graves (Harrison & Heyd 2007) and the following Bell Beaker and Early Bronze Age phenomena, it remains to be seen exactly what factors contributed to the development of these systems. It may be that there were changes in subsistence practices, perhaps involving a rising importance of animal herding that subsequently required higher mobility (for a discussion see Dörfler & Müller 2008), but considering the obvious diversity in subsistence patterns present in different Corded Ware groups, such an explanation would seem appropriate for the transformation in some regions, but surely not for the eastern hunterfisher-gatherer groups of the Baltic (Bläuer & Kantanen 2013). Also, trade with amber and copper might have played its role, but there are so far no indications for a significant rise in quantity or reach of these two materials in connection with Corded Ware graves or settlements (Furholt 2003, 125–7).

The impacts of animal traction and the wagon are also to be taken into account, as they are present since 3400 BC (Mischka 2011) but does at least not play any visible role in Corded Ware burial rituals, very much in contrast to the previous periods (Johannsen & Laursen 2010). There is no evidence for horse riding, but the domesticated horse seems to be present in central Europe since before 3000 BC (Becker 1999) and have also been found in Corded Ware settlements (Becker 2008), but again the evidence of domesticated horses is much more abundant in the period before 3000 BC.

So, concerning amber and copper exchange, or the impact of the wheel and animal traction, there is the recurrent motive of stronger evidence for the period before 3000 BC than during or in connection to Corded Ware finds after 2700 BC.

corded-ware-groups-europe-chronology
Summary table for the chronological positions (extent of name plus vertical lines) of the most important traditional archaeological ‘cultures’, ‘Groups’ or pottery styles discussed in this paper. Note that the definitions of those units are far from consistent or comparable, because they derive from different national and regional research traditions. Bold letters indicate a unit connected to the Corded Ware phenonomenon

Conclusion

The evidence strongly points towards a long period of coalescence from 3000 to 2700 BC, when several innovations in burial customs, pottery, and tool types sprung forth from different places and subsequently spread via different networks of exchange and interaction. These surely showed a significant rise in scale, reach, and impact on local practices, but the same is true for the contemporary Globular Amphora and Yamnaya ‘Cultures’. This exchange resulted, roughly spoken, in a phenomenon like the A-Horizon.

(…)

Thus, it seems reasonable to explain the wide regional reach of those Corded Ware elements as the result of a general increase in mobility and thus an increase in the spatial extension of regional networks, triggered by the long-term effects of technological innovations and connected economic and social transformations in Europe since 3400 BC. It is the increase in mobility and regional networks that is new to the European Neolithic Societies after this time, and it is not only the Corded Ware elements, that are spread through these channels but also Yamnaya, Globular Amphorae, Bell Beaker ‘Cultures’, and copper and bronze artefacts in later periods. Those are archaeological classification units, heuristic tools for the ordering of finds, while brushing over variability and overlapping traits, and so they should not be confused with real social groups.

corded-ware-regions-network
Network analysis based on the quantitative occurrence of Corded Ware pottery forms, pottery ornamentation styles, tools, weapons and ornaments as stated in Table 1, based on the catalogues given in Table 2, line thickness representing similarity

As a summary, we can say that there is still much work to be done on the origins and expansion of the Corded Ware culture, and that speculative interpretations of recent genetic papers (especially since 2015), based solely on scarce genetic finds, are not doing much in favour of sound anthropological models by connecting directly Yamna to Corded Ware (and the latter to Bell Beaker), as the multiple new anthropological ‘steppe’ models (and their unending revisions due to the gradual corrections from ‘Yamnaya’ to ‘steppe’ admixture in genetic papers) are showing.

Featured image, from Furholt’s article: Map of the Corded Ware regions discussed for central Europe. The dark shading indicates those regions where Corded Ware burial rituals are present regularly.

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