Dissecting the biological and pathological consequences of a major lifestyle transition – LifeChange

LifeChange aims at developing an original line of research to track the biological consequences of the societal changes undergone by the Yakut people of Far Eastern Siberia, after the colonization of the region by Russians in the 17th century, and to evaluate how the major lifestyle transition that followed still conditions the health status within the present-day population. The recent history of Yakut people provides a unique natural experiment in which contact between populations showing traditional and modern lifestyles took place in the coldest region in the northern hemisphere. Russians introduced carbohydrate-rich cereals in the region for the first time, which increasingly impacted the traditionally protein-rich, meat-driven Yakutian diet over time. They brought along new germs, such as smallpox and tuberculosis, causing massive epidemiological outbreaks that decimated the immunologically naive native population. The Russian expansion in the region also dramatically impacted the sociocultural sphere, including an increasing settlement of native groups and a gradual conversion to Christianity. The last 5 centuries of the Yakut history thus provides a paradigm in which (1) the biological consequences of transitioning from traditional to modern lifestyle can be measured in situ, and (2) direct information about important human pathogens and the genetic factors underlying their virulence can be collected. By coupling truly complementary state-of-the-art approaches in ancient DNA research, (meta)(epi)genomics, immunogenetics and sociology for the first, we will track the history of changes in the genome, epigenome and oral microbiome of Yakut people from the 16th century onwards. This will allow us to measure the impact of Russian colonization, which resulted in dramatic societal changes and lifestyle shifts. We will also evaluate how social and animal exposure condition patterns of epigenetic variation, oral microbiota composition and zoonotic disease risks in present-day individuals. Our project will provide the first empirical test for important medical hypotheses, such as the hygiene and old-friend hypotheses, which posit that present-day populations are maladapted to modern lifestyle and that recent changes in lifestyle have driven major biological changes, including some of major health relevance. Importantly, our project presents a novel paradigm for the study of the biological consequences of European colonization, integrating archaeological, historical, ethnological, medical and biological proxies within a single, consistent framework.