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Understanding the microbial history of the Pacific Islands: Insights on human adaptations to new environments

Thursday, December 1, 2022 at 4:00pm

Museum of Natural and Cultural History
1680 E 15th Avenue, Eugene, OR

We hope you will join us on Thursday, December 1, 2022 at 4:00 PM in the Museum of Natural and Cultural History, for a talk by Laura Weyrich, Associate Professor in the Department of Anthropology at Penn State University, entitled “Understanding the microbial history of the Pacific Islands: Insights on human adaptations to new environments. This talk is free and open to the public.


The settlement of the Eastern Pacific (the “Polynesian triangle” from Hawaii to Rapa Nui to Aotearoa New Zealand) represents the last great phase of prehistoric human exploration and expansion. Despite this incredible feat, we know incredibly little about immediate and long-term post-arrival impacts on human physiology and health. Arrival in unique locations with varied access to resources, new disease exposures, and altered diets likely resulted in differential adaptive strategies across distinct archipelagos. A new method – assessing ancient oral microbiomes within calcified dental plaque (calculus) – can provide insights into how humans adapted to new environments. Here, we sequenced ancient DNA preserved within dental calculus from three different Pacific Island Nations (Palau, Tahiti, and Aotearoa) in concert with local collaborators and communities. Distinct oral microbial communities were linked to the arrival in Central-East Polynesia, as well as settlement on individual archipelagos (i.e., in Tahiti), suggesting that settling in new locations may have altered microbes within these Ancestors.  Further, oral microbiome shifts were linked with different environments and ecologies, as distinct microbiomes were present in people living on sand atolls versus forested high-islands. Several of these microbes associated with these different ecologies are linked to the modern-day presence of oral disease, providing unique opportunities to examine the origins of chronic disease in the Pacific Islands. Lastly, a phylogenomic approach to reconstruct the evolutionary history of 10 different vertically-inherited oral microbes revealed past relationships between people in the Pacific, suggesting that microbes were shared between island communities, likely through interisland connections and trade. A key oral species within the Anaerolineaceae family also corroborated large-scale patterns of human migration, suggesting that these microbial signatures can potentially be leveraged to identify Pacific Islander Ancestors with minimally destructive sampling approaches. Overall, our work reveals how microbial signatures in Ancestors can illuminate novel insights into human adaptation to new environments.

Event Type

Lectures & Presentations, Lecture, Diversity and Multiculturalism, International


Division of Global Engagement, Global Studies Institute, Center for Asian and Pacific Studies



Free and open to the public


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