ABSTRACT

Humans are home to about 100 trillion bacteria, fungi, and viruses, collectively known as your microbiome. van Leeuwenhoek was the first to visualize microbes under a microscope over four hundred years ago. Now the question is, “Can a DNA sequencing instrument be used as an equally powerful microscope to elucidate the microbial communities that reside in and on our bodies”? DNA sequencing technology, developed to empower the human genome project, enables us to sequence a fully complete bacterial genome in hours and explore the myriad culturable and unculturable microbial communities at high resolution. My work explores the varied topography of human skin to study how the body’s microenvironments influence the functional and taxonomic composition of microbial communities. We performed high throughput genomic sequencing surveys to investigate the topographical and temporal complexity of skin microbial communities from 20 skin sites in healthy adults to identify the hundreds of bacteria and fungi that colonize distinct skin niches. Significant differences were observed in the bacterial species predominating skin sites, shaped by microenvironments: sebaceous, moist, and dry. We identified strain-level variation of dominant species as heterogeneous and multiphyletic, and largely stable over time. This work, which defines the dual influence of biogeography and individuality on microbial composition and function, is foundational for human disease studies investigating inter-kingdom interactions, metabolic changes, and strain tracking.

About the Speaker:

Julie Segre, Ph. D., is a Senior Investigator at the National Human Genome Research Institute, NIH. Her research focuses on microbial genomics, investigating both hospital pathogens and the diversity of commensal skin organisms. Segre’s research integrates DNA sequence technology, algorithm development and diagnostic clinical microbiology. Segre has published extensively with 30 research articles (19 as senior author) and 5 review articles in the last 5 years in journals including Science, Nature, Science Translational Medicine, PNAS, Genome Biology and Genome Research.

Segre’s research has defined the normal human skin bacterial and fungal communities, enabling studies of alterations associated with pediatric atopic dermatitis and primary immunodeficiency. Segre’s research also focused on integrating whole genome sequencing of hospital pathogens both to study nosocomial transmission and to develop a national surveillance network.

Segre received the 2013 Service to America Medal, together with NIH Clinical Center epidemiologist Tara Palmore, for deploying genomic sequencing to guide hospital outbreak containment. Segre received her B.A. from Amherst College in 1987, graduating Phi Beta Kappa and summa cum laude in mathematics. She obtained her PhD in 1996 in Genetics from MIT, advised by Eric S. Lander and received postdoctoral training in skin biology mentored by Elaine Fuchs. Segre was recruited as a new investigator to NHGRI/NIH in 2000 and received tenure in 2007. Segre was elected to the Board of Trustees of Amherst College in 2011.