Despite its global economic importance, basic questions about the origins and role of dairying in early human societies are still unanswered. The inability to digest milk sugar, or lactose, in adults is an ancestral human trait and only a few human populations have genetic variants that allow continued milk digestion into adulthood, a trait known as lactase persistence. However, lactase persistence does not consistently appear in the archaeological record until more than 5,000 years after the origins of dairying and some dairying populations do not have it at all. This has left archaeologists with a puzzling problem, a “milk paradox,” regarding how and why ancient peoples developed milk into a dietary resource and what other factors besides lactase persistence may have been involved in this process.
There is now a growing body of evidence that microbes have played important roles in prehistoric dairying. Our team uses cutting-edge techniques to test, among other things, hypotheses regarding the relationship between the gut microbiome and lactose digestion in Mongolian dairy herders, as well as how dairying arose in Mongolian prehistory.
Archaeology
People in Central Asia today enjoy a rich dairying tradition, but the origins and antiquity of this vital culinary practice are poorly understood. Skeletal remains of domesticated cattle, horses, sheep and goats recovered from archaeological sites located in Mongolia suggest that dairying spread to the eastern steppes during the Bronze Age, but the precise nature of how these animals were used remains unknown. In addition, we still lack knowledge about how these animals genetically relate to others found throughout Eurasia, which can provide key details about ancient animal dispersals and human mobility. To address these questions, the DairyCultures project explores the archaeology of dairying in Mongolia through cutting-edge scientific methods of palaeogenomics and ancient protein analysis.
To identify ancient dairy consumption, the DairyCultures project studies milk proteins from archaeological teeth. Previous work by DairyCultures team members has shown that milk proteins can become archived in calcified tooth plaque (dental calculus) which can survive for hundreds or even thousands of years. By extracting and identifying these ancient milk proteins, we can directly observe whether that person ate dairy products and which animal species produced the milk.
The DairyCultures team will also turn to ancient DNA to unlock more information about the earliest domesticated animals to reach Mongolia and how people bred and exchanged livestock over millennia. By analysing DNA preserved in animal bones, the project will investigate the complex genetic histories of animals recovered from archaeological sites in order to trace initial dispersal routes and the dynamics of selective pressures that gave rise to the vibrant dairying traditions of the steppes today.
Biology
The DairyCultures project is examining how bacteria closely connect humans, animals, their food and their shared environment. While dairy foods are an important dietary component for Mongolians, lactose malabsorption (poor digestion of the milk sugar lactose) is believed to be highly prevalent, similar to other East Asian populations. However, recently the foods that people eat and the composition and function of the gut microbiome (the bacterial ecosystem found in the human gut) have been shown to be linked. Microbial adaptation – through culinary manipulation and gut microbiome alteration – is therefore likely to play an important role in the digestion of this important dietary staple.
The DairyCultures project will test the link between the consumption of dairy foods and the gut microbiome by collecting data from:
- Human gut microbiome samples from urban and rural households in Mongolia,
- Lactase persistence genotypes and lactose digestion phenotypes,
- Household microbiome samples, including swabs of cooking tools, floors and surfaces,
- Microbiome samples from dairy livestock, including dung and swabs of skin/fur.
This will enable an understanding of the integration of microbes in food and in the home, as well as the shared microbial ecosystems between humans, animals and their environments.
Ethnography
Milk and dairying are an integral part of Mongolia’s cuisine, culture and customs. In pastoral society, dairy products such as aaruul (dried curds) and süütei tsai (milk tea) provide herders with important seasonal and perennial nutritional resources. Moreover, milk has many cultural connotations and the use of dairy products plays an important role in various rituals and festivities. Accordingly, traditions of dairying play a key-role in the history and present of mobile pastoralism in Mongolia.
Here, we will introduce you to various processes of Mongolian pastoral dairying as well as to some of the manifold Mongolian cultural practices that involve milk and dairy products.
You can audio-visually explore our ethnographic work at our Ethnographic Database!
