5,000-year-old milk proteins point to the importance of dairying in eastern Eurasia

5,000-year-old milk proteins point to the importance of dairying in eastern Eurasia

Recent findings push back estimates of dairying in the eastern Steppe by more than 1,700 years, pointing to migration as a potential means of introduction

 

Today dairy foods sustain and support millions around the world, including in Mongolia, where dairy foods make up to 50% of calories consumed during the summer. Although dairy-based pastoralism has been an essential part of life and culture in the eastern Eurasian Steppe for millennia, the eastward spread of dairying from its origin in southwest Asia and the development of these practices is little understood. The current study, led by Shevan Wilkin and Jessica Hendy of the Max Planck Institute for the Science of Human History, presents the earliest evidence for dairy consumption in East Asia, circa 3000 BCE, and offers insights into the arrival and evolution of dairy pastoralism in prehistoric Mongolia.

dairying Eurasia
These are horses on the steppe. Credits: Björn Reichhardt

Earliest dairy consumption & a possible path of entry

The highly mobile nature of pastoralist societies and the severe winds of the Eastern Steppe make detecting occupied sites with direct evidence into the lives and culture of ancient Mongolians exceedingly rare. Instead, the researchers looked for clues in ritual human burial mounds, often marked by stone monuments and occasionally featuring satellite animal graves.

In collaboration with the National University of Mongolia, researchers analyzed dental calculus from individuals ranging from the Early Bronze Age to the Mongol Period. Three-quarters of all individuals contained evidence that they had consumed dairy foods, which demonstrates the widespread importance of this food source in both prehistoric and historic Mongolia. The study's results include the earliest direct evidence for dairy consumption in East Asia, identified in an individual from the Afanasievo site of Shatar Chuluu, which dates to roughly 3000 BCE. Previous DNA analysis on this individual revealed non-local genetic markers consistent with Western Steppe Herder populations, presenting Early Bronze Age Afanasievo migrations westward via the Russian Altai as a viable candidate for the introduction of dairy and domestic livestock into eastern Eurasia.

Multiple different animal species were used for their milk

dairying Eurasia
These are sheep and goat herds in Mongolia. Credits: Björn Reichhardt

By sequencing the milk proteins extracted from the dental calculus, the scientists were able to determine which animal species were being used for dairy production, and thereby help to trace the progression of domestication, dairying, and pastoralism in the region. "Modern Mongolians use cow, sheep, goat, yak, camel, horse and reindeer for milk today, yet when each of these species were first utilized for dairy in Mongolia remains unclear," says Shevan Wilkin, lead author of the study. "What is clear is that the crucial renewable calories and hydration made available through the incorporation of dairying would have become essential across the arid and agriculturally challenging ancient Eastern Steppe."

The earliest individuals to show evidence of dairy consumption lived around 5000 years ago and consumed milk from ruminant species, such as cattle, sheep, and goats. A few thousand years later, at Bronze Age sites dated to after 1200 BCE, the researchers find the first evidence of horse milk consumption, occurring at the same time as early evidence for horse bridling and riding, as well as the use of horses at ritual burial sites. In addition, the study shows that during the Mongol Empire circa 1200-1400 CE, people also consumed the milk of camels. "We are excited that through the analysis of proteins we are able to see the consumption of multiple different animal species, even sometimes in the same individual. This gives us a whole new insight into ancient dairying practices" says Jessica Hendy, senior author of the study.

Millenia after the first evidence of horse milk consumption, horses remain vital to the daily lives of many in modern Mongolia, where mounted pastoralists rely on them to manage large herds of livestock, transport people and supplies, and provide a primary source of meat and milk. "Our findings suggest that the incorporation of horses into dairy pastoralism in Eastern Eurasia was closely linked to a broader economic transformation in the use of horses for riding, movement, and diet," says William Taylor of the University of Colorado-Boulder, one of the study's coauthors.

Although the earliest individual sampled in this study showed evidence of dairy consumption, the researchers hope future studies will examine individuals from previous time periods. "In order to form a clearer picture of the origins of dairying in this region, we need to understand the impact of western steppe herder migrations and confirm whether dairying was occurring in Mongolia prior to their arrival," Shevan Wilkin concludes.

dairying Eurasia
This is a horse burial at Morin Mort, Mongolia. Credits: William Taylor

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Publication information:

Title: Dairy pastoralism sustained Eastern Eurasian steppe populations for 5000 years

Authors: Shevan Wilkin, Alicia Ventresca Miller, William T.T. Taylor, Bryan K. Miller, Richard W. Hagan, Madeleine Bleasdale, Ashley Scott, Sumiya Gankhuyg, Abigail Ramsoe, S. Uliziibayar, Christian Trachsel, Paolo Nanni, Jonas Grossmann, Ludovic Orlando, Mark Horton, Philipp W. Stockhammer, Erdene Myagmar, Nicole Boivin, Christina Warinner, Jessica Hendy

Publication: Nature Ecology & Evolution

DOI: 10.1038/s41559-020-1120-y

 

Press release from the Max Planck Institute for the Science of Human History / DE


Dramatic change in ancient nomad diets coincides with expansion of networks across Eurasia

Dramatic change in ancient nomad diets coincides with expansion of networks across Eurasia

nomad pastoralists diets
Map of millet and wheat/barley consumption over time: a) 1000-500 cal BC, b) 500-200 cal BC, and c) 200 BC-AD 400. Credit: Map of millet and wheat/barley consumption over time: a) 1000-500 cal BC, b) 500-200 cal BC, and c) 200 BC-AD 400

A meta-analysis of dietary information recorded in the bones of ancient animals and humans recovered from sites scattered across the Eurasian steppe, from the Caucasus region to Mongolia, demonstrates that pastoralists spread domesticated crops across the steppe through their trade and social networks. Researchers from Kiel University sifted through previously published stable isotopic data and applied new quantitative analyses that calibrate human dietary intake against environmental inputs. The results have allowed them to better isolate the timing of the incorporation of agricultural products into the diets of pastoral nomads and, crucially, link burgeoning socio-political networks to this dietary transformation.

Through a big data project that explored over a thousand stable isotope data points, researchers were able to find evidence for an early transition to agriculture - based on dietary intake across Eurasia. "Our understanding of the pace of crop transmission across the Eurasian steppe has been surprisingly unclear due in part to a focus on the excavation of cemeteries, rather than settlements where people threw out their food," says Alicia Ventresca Miller, lead author, formerly of Kiel University and currently at the Max Planck Institute for the Science of Human History. "Even when settlement sites are excavated, the preservation of carbonized seed remains is often poor. This is what makes stable isotope analyses of human remains from this region so valuable - it provides direct insights into the dietary dynamics of ancient pastoralists who inhabited diverse environments."

Millet spreads across the Eurasian steppe

Millet, originally domesticated in China, appears to have been occasionally consumed at low levels by pastoralists inhabiting the far-flung regions of Siberia and southeastern Kazakhstan, possibly as early as the late third millennium. This initial uptake of millet coincided with the expansion of trans-regional networks across the steppe, when objects and ideas were first regularly exchanged over long-distances.

However, it was not until a thousand years later that millet became a regular feature of pastoralist diets. This timing coincides with the intensification of complex political structures at the transition to the Iron Age. Burgeoning socio-political confederations drove a marked increase in the exchange of costly prestige goods, which strengthened political networks - and facilitated the transfer of cultigens.

Wheat and Barley in the Trans-Urals

Despite taking part in these political networks, groups in the Trans-Urals invested in wheat and barley farming rather than millet. A dietary focus on wheat and barley may have been due to different farming techniques, greater water availability, or a higher value on these cultigens. "Our research suggests that cultigens were converted from a rare luxury during the Bronze Age to a medium demarcating elite participation in political networks during the Iron Age," states Cheryl Makarewicz of Kiel University.

Regional variation in millet consumption

While herding of livestock was widespread, not all regions adopted millet. In southwest Siberia, dietary intake was focused on pastoral animal products and locally available wild plants and fish. In contrast, the delayed adoption of millet by populations in Mongolia during the Late Iron Age coincides with the rise of the Xiongnu nomadic empire. "This is particularly interesting because it suggests that communities in Mongolia and Siberia opted out of the transition to millet agriculture, while continuing to engage with neighboring groups," explains Ventresca Miller.

This study shows the great potential of using the available isotope record to provide evidence for human dietary intake in areas where paleobotany is understudied. Further research should clarify the exact type of grains, for example broomcorn or foxtail millet, were fundamental to the shift in dietary intake and how networks of exchange linked different regions.

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Original publication:

Ventresca Miller and Makarewicz, Intensification in pastoralist cereal use coincides with the expansion of trans-regional networks in the Eurasian Steppe, Scientific Reports (2019). DOI: https://doi.org/10.1038/s41598-018-35758-w

 

Press release from Kiel University / Christian-Albrechts-Universität zu Kiel


Inner Eurasia

Details of the history of inner Eurasia revealed by new study

Details of the history of inner Eurasia revealed by new study

Researchers combining genetics, archaeology, history and linguistics have gained new insights into the history of inner Eurasia, once a cultural and genetic crossroads connecting Europe and Asia

Inner Eurasia
Children from one of the Tajikistan communities included in the study. Credit: Elena Balanovska

An international team of researchers has combined archaeological, historical and linguistic data with genetic information from over 700 newly analyzed individuals to construct a more detailed picture of the history of inner Eurasia than ever before available. In a study published in Nature Ecology & Evolution, they found that the indigenous populations of inner Eurasia are very diverse in their genes, culture and languages, but divide into three groups that stretch across the area in east-west geographic bands.

Inner Eurasia, including areas of modern-day Armenia, Georgia, Kazakhstan, Moldova, Mongolia, Russia, Tajikistan, Ukraine and Uzbekistan, was once the cross-roads connecting Asia and Europe, and a major intersection for the exchange of culture, trade goods and genes in prehistory and historical periods, including the era of the famous Silk Road.

This vast area can also be divided into several distinct ecological regions that stretch in largely east-west bands across Inner Eurasia, consisting of the deserts at the southern edge of the region, the steppe in the central part, taiga forests further north, and tundra towards the Arctic region. The subsistence strategies used by indigenous groups in these regions largely correlate with the ecological zones, for example reindeer herding and hunting in the tundra region and nomadic pastoralism on the steppe.

Despite the long and important history of inner Eurasia, details about past migrations and interactions between groups are not always clear, especially in prehistory. "Inner Eurasia is a perfect place to investigate the relationship between environmental conditions and the pattern of human migration and mixture, as well as changes driven by cultural innovations such as the introduction of dairy pastoralism into the steppe," states Choongwon Jeong of the Max Planck Institute for the Science of Human History, co-first and senior author of the paper. In order to clarify our understanding of some of the nuances of the history of the region, an international team of researchers undertook an ambitious project to use modern and ancient DNA from a broad geographic range and time period, in concert with archaeological, linguistic and historical information, to clarify the relationships between the different populations. "A few ethnic groups were studied previously," comments Oleg Balanovsky from the Vavilov Institute of General Genetics in Moscow, also co-first author, "but we conducted more than a hundred field trips to study this vast region systematically, and reached communities speaking almost all of the Inner Eurasian languages".

Three distinct east-west groupings

For this study, the researchers analyzed DNA from 763 individuals from across the region as well as reanalyzed the genome-wide data from two ancient individuals from the Botai culture, and compared those results with previously published data from modern and ancient individuals. They found three distinct genetic groupings, which geographically are arranged in east-west bands stretching across the region and correlating generally to ecological zones, where populations within each band share a distinct combination of ancestries in varying proportions.

The northernmost grouping, which they term "forest-tundra", includes Russians, all Uralic language-speakers, which includes Hungarian, Finnish and Estonian, and Yeniseian-language speakers, of which only one remains today and is spoken in central Siberia. The middle grouping, which they term "steppe-forest", includes Turkic- and Mongolic-speaking populations from the Volga and the region around the Altai and Sayan mountains, near to where Russia, China, Mongolia and Kazakhstan meet. The southernmost grouping, "southern-steppe", includes the rest of Turkic- and Mongolic-speaking populations living further south, such as Kazakhs, Kyrgyzs and Uzbeks, as well as Indo-European-speaking Tajiks.

Previously unknown genetic connections revealed

Because the study includes data from a broad time period, it is able to show shifts in ancestry in the past that reveal previously unknown interactions. For example, the researchers found that the southern-steppe populations had a larger genetic component from West and South Asia than the other two groupings. This component is also widespread in the ancient populations of the region since the second half of the first millennium BC, but not found in Central Kazakhstan in earlier periods. This hints at a population movement from the southern-steppe region to the steppe-forest region that was previously unknown.

"Inner Eurasia has functioned as a conduit for human migration and cultural transfer since the first appearance of modern humans in this region. As a result, we observe deep sharing of genes between Western and Eastern Eurasian populations in multiple layers," explains Jeong. "The opportunity to find direct evidence for the hidden old layers of admixture, which is often difficult to appreciate from present-day populations, is very exciting."

"We found not only corridors, but also barriers for migrations," adds Balanovsky. "Some of them separate the historical groups of populations, while others, like the distinct barrier following the Great Caucasus mountain ridge, were obviously shaped by the geographic landscape."

Geographic locations of the Eneolithic Botai, groups including newly sampled individuals, and nearby groups with published data. The map is overlayed with ecoregional information, divided into 14 biomes downloaded from https://ecoregions2017.appspot.com/ (credited to Ecoregions 2017 © Resolve). Credit: Jeong & Balanovsky et. al. 2019. The genetic history of admixture across inner Eurasia. Nature Ecology & Evolution, http://dx.doi.org/10.1038/s41559-019-0878-2.

Two ancient individuals resequenced in this study originated from the Botai culture in Kazakhstan where the horse was initially domesticated. Analysis of the Y-chromosome (inherited along the paternal genealogical lines) revealed a genetic lineage which is typical in the Kazakh steppe up to the present day. But analysis of the autosomes, which both parents contribute to their children, show no trace of Botai ancestry left in present-day people, likely due to repeated migrations into the region both from the west and the east since the Bronze Age.

The researchers emphasize that their model of three groupings does not perfectly explain all known populations and that there are examples of both outliers and intermediate groups. "It is important to organize a future study for further sampling of sparsely populated regions between the clines, for example, Central Kazakhstan or East Siberia," states Johannes Krause, also of the Max Planck Institute for the Science of Human History, and senior author of the paper.

Researchers from the study conducting field work along the Amur River. Credit: Yuri Bogunov

Press release from the Max Planck Institute for the Science of Human History / Max-Planck-Institut für Menschheitsgeschichte