This episode of "Matters Microbial" features Dr. Laura Weyrich, Associate Professor of Anthropology and Bioethics at Pennsylvania State University, who discusses her pioneering research on the paleo oral microbiome. The conversation delves into the methodologies of extracting and analyzing ancient DNA from calcified dental plaque (dental calculus) of Neanderthals and early modern humans, emphasizing the critical importance of rigorous contamination controls in low-biomass studies. Dr. Weyrich highlights significant shifts in the human oral microbiome, linking dramatic changes to the advent of agriculture and later the Industrial Revolution, leading to a "disease state" in modern industrialized populations. She also presents findings on Neanderthals' remarkable oral health and evidence of microbial exchange with early humans. The discussion further explores the ethical dimensions of ancient DNA research, including community engagement and the rights of Indigenous populations regarding their biological heritage. Ultimately, Dr. Weyrich outlines the translation of this paleo-microbiome understanding into the development of oral microbiome transplants (OMT) as a novel preventative biotechnology for modern dental diseases, driven by a passion to challenge scientific dogma and improve global health outcomes.
Summarizing Neanderthal Oral Health, Ancient Bacteria, and DNA
0:26 Welcome & Introduction: Host Dr. Mark Martin welcomes Dr. Laura Weyrich, Associate Professor of Anthropology and Bioethics at Pennsylvania State University, to discuss her research on the paleo oral microbiome, ancient bacteria, and DNA.
4:34 Studying the Deep Past: Dr. Weyrich explains that ancient DNA (aDNA) is primarily used to study the deep past, surviving in ancient individuals and sediments for long periods. Other methods include ancient proteins and lipids.
8:51 Ethical Considerations in Ancient DNA: Dr. Weyrich emphasizes the crucial role of ethics in her work, particularly recognizing Indigenous rights and histories in research on human remains. She highlights the need for community engagement and fair compensation when leveraging microbes from Indigenous people for biotechnological applications.
8:51 Addressing Contamination: A significant challenge in ancient DNA research is contamination from reagents ("kitome") and the environment. Dr. Weyrich's lab employs extensive controls, including swabbing labs, museums, field sites, and using inside-the-tooth controls, and decontaminating samples with bleach and UV, to ensure the authenticity of ancient microbial signatures.
20:25 Dental Calculus as a Time Capsule: Dental calculus (calcified dental plaque) is the primary sample type for reconstructing ancient oral microbiomes. This "rock-hard matrix" preserves microbes from a person's living mouth, allowing scientists to study past microbial communities and their association with health and disease.
24:30 Oral Microbiome Shifts with Lifestyle: Research shows a dramatic shift in the oral microbiome with the adoption of agriculture (around 7,500 years ago in Europe). Hunter-gatherers had excellent oral health, while agriculturalists developed disease-associated microbiomes due to increased carbohydrate consumption. Further shifts occurred during the Industrial Revolution and post-World War II ("great acceleration").
29:41 Modern Oral Microbiome as a "Disease State": Dr. Weyrich argues that the modern industrialized oral microbiome is largely a "disease state," highly adapted to sugar and linked to common issues like cavities and periodontal disease. Toothbrushing, while necessary now, is a response to this evolutionary mismatch.
33:41 Link to Systemic Diseases: Periodontal disease is a risk factor for numerous chronic systemic diseases, including gastrointestinal cancers, Alzheimer's, heart disease, diabetes, and rheumatoid arthritis, underscoring the importance of oral health for overall well-being.
39:19 Oral Microbiome Transplants (OMT): Dr. Weyrich's company, Microversal LLC, is developing OMT, transplanting diverse microbial communities (150-230 species) from "ultra-healthy" modern donors to leverage ancient ecological knowledge. These communities are selected for their ability to outcompete modern pathogens, not by culturing ancient microbes directly.
43:19 Neanderthal Oral Health & Microbial Exchange: Neanderthals had "amazing oral health" and excellent teeth. Research indicates they shared many oral microbes with early humans, with evidence of microbial exchange between the two groups. Diet was a significant factor influencing their oral microbiome.
1:04:51 Key Takeaways: Dr. Weyrich encourages listeners to challenge scientific dogmas, recognize science as an iterative learning process, and pursue their passions. Her personal motivation stems from translating ancient microbiome knowledge into new preventative technologies to address widespread chronic diseases and improve health.