Ancient foods, fiber, and bugs: microbiomes and functional genetics to discover past human behaviors
Lecture by Stephanie Schnorr, Konrad Lorenz Institute, Austria.
Humans have curious dietary proclivities with regard to their evolutionary history. Humans are the only ape to cultivate and process their food post extraction, and it is thought that these activities enable humans to develop and maintain a large metabolically expenses brain.
Anthropologists take great interest in the activity of human food production, which is often contrasted with that of modern great apes, in order to reconstruct the intervening 6 million years of evolution since the last common ancestor between humans and chimpanzees.
Yet, observations of modern human hunter-gatherers demonstrates that extensive food processing is not essential for survival, and that although food processing technologies were developed thousands of years ago, these activities are not always incorporated into the food systems of various human societies. Notably, the Hadza hunter-gatherers of Tanzania subsist on a variety of wild foods including berries, tubers, baobab, honey, and wild game, and yet food processing in preparation for consumption is rare or situational, despite the high fiber- and resistant starch-content of their foods.
The human digestive tract is not well suited to digesting refractory foods, and there is an open question as to how much nutrition groups like the Hadza can obtain from their challenging high-fiber diet. Selection for increased copy number of the salivary amylase gene as well as the function of gut microbiota may give insight about the behaviors relating to diet and nutritional acquisition in the course of human evolution.
Investigations that model the activity or expression of genetic and microbial traits provide anthropologists with a new framework for thinking about how ancient human societies subsisted in the absence of extensive food processing technology, and to revisit assumptions about what dietary components may be optimal for human health. In this presentation
I talk about the role of plant foods in the human diet and their evolutionary legacy. In doing so, I present some of my earlier research on wild plants the came about from working with the Hadza, and move on to demonstrate evidence for how the gut microbiome can be interrogated as to its role in nutritional provisioning as well as models I use for understanding the physiological relevance of the salivary amylase copy number increase. I end with more recent efforts to reconstruct the microbiome of ancient populations, the techniques used, and a discussion on the state of this research and what may be expected in the future.
Stephanie Schnorr is a biological anthropologist who studies the role of diet and the gut microbiome in human evolution. Stephanie began this line of inquiry during her dissertation research at the Max Planck Institute for Evolutionary Anthropology by studying wild underground storage organs (or tubers) consumed by modern human hunter-gatherers, in which the microbiome plays a critical role.
After her PhD, Stephanie moved to the University of Oklahoma to focus more specifically on microbiomes in anthropology at the Laboratories of Molecular Anthropology and Microbiome Research. While there, she used her post-doctoral time to research ancient microbiomes as well as the microbiome of edible termites, and has since moved on to pursue a wide variety of projects on topics ranging across human diet, digestion, and gut microbiome.
Stephanie is currently a visiting researcher at the KLI and holds an NSF Postdoctoral Fellowship out of the University of Nevada, Las Vegas to study the evolutionary conditions surrounding a selective increase in the human alpha-amylase gene copy number compared to other extant hominids and archaic humans. This line of research delves into the relationship between humans and starch-containing foods under the premise that these starchy foods were essential for early hominin occupation of savanna-mosaic environments, as well as ancient human migrations to foreign environments and their ability to cope with major ecological upheavals.
Stephanie continues to work on these varied topics of diet and microbiome in human evolution as these occupy core foci of her general interest in research on human digestive and metabolic physiology.