By Alyssa Bader, Sealaska Heritage Postdoctoral Fellow
As a National Science Foundation postdoctoral research fellow at Sealaska Heritage Institute, I will be working under the mentorship of Dr. Rosita Worl to explore the relationship between diet and the community of bacteria living in our mouths, called the oral microbiome. Through the oral microbiome, I hope to identify some of the biological processes underlying how our traditional foods support our health and wellbeing. I will be posting updates about my research activities throughout my two-year fellowship period.
Last month, I visited the Metlakatla First Nation in British Columbia to continue a project we developed investigating how a marine-based diet has shaped the composition of the oral microbiome in the Coast Tsimshian community. In 2018, with permission from the community, I extracted ancient DNA from the dental plaque of Ancestors whose burials had previously been excavated during archaeological projects in the Prince Rupert Harbour region. I then used the ancient DNA from this dental plaque to reconstruct what types of bacteria dominated the oral microbiome of the Coast Tsimshian community thousands of years ago. By comparing the data from the Ancestors to oral microbiome samples collected from living community members using mouth swabs, I was able to assess how the oral microbiome has changed over time.
My research with Old Metlakatla is part of a long-term collaboration between the community and Dr. Ripan Malhi, a molecular anthropologist at the University of Illinois at Urbana-Champaign. This collaboration focuses on using genomic methods to understand the biological consequences of European colonization. One of the questions my research with the community addresses is how new foods incorporated into the diet as a result of European colonization may be impacting the composition and function of the oral microbiome.
During the project, we realized we wanted to know more about how the different sample types we used for the study–DNA from the hardened dental plaque of Ancestors versus DNA from swabs of the gumline of descendant community members–might influence our results. The research methods used in any study shape the data that is generated, so it is important to reflect on these influences when we interpret the data. In this case, we needed to better understand if any differences observed between the oral microbiomes of the Ancestors and descendant community members were really correlated with changes in diet over time, or actually a result of comparing two different sample types.
So during my recent visit to Old Metlakatla, I worked with Barbara Petzelt and Joycelynn Mitchell from the Treaty Office and Amanda Babich, a dental hygienist based in Prince Rupert, to collect both dental plaque scrapings and mouth swab samples from a group of community members. After the plaque and swab samples were collected, I brought them to the Malhi Molecular Anthropology Lab at the University of Illinois, where I extracted the DNA. This DNA is currently being sequenced at the University of Illinois.
Once the sequencing is complete, I will be able to analyze the DNA extracted from the microbes living in and around the dental plaque. I will identify, based on their DNA, which microbes are present in each sample and if there are any significant differences in the microbial community between the two sample types collected from each participant. This information will improve our interpretations of how the oral microbiome of the Coast Tsimshian community in Prince Rupert has changed over time. It will also help inform the sample collection methods used in future oral microbiome research projects, such as the project we are developing now, here in Southeast Alaska, to investigate how maintaining traditional foods in our diet influences the composition and function of our oral microbiome today.
Please stayed tuned – I will be posting more updates about our research activities throughout my fellowship at Sealaska Heritage Institute.
From left: Barb (Metlakatla First Nation Treaty Office), Amanda (dental hygienist), me, and Joycelynn (Metlakatla First Nation Treaty Office) outside the Metlakatla Health Center where we did all the sample collection during the most recent visit.
