"Now that the draft sequence of the human genome is complete, it's critical that we study the environmental forces that regulate our gene expression," says principal investigator Jeffrey I. Gordon, M.D., the Dr. Robert J. Glaser Distinguished University Professor and head of the Department of Molecular Biology and Pharmacology. "Humans enjoy mutually beneficial relationships with billions of bacteria that live in our gut. Discovering how these microbes manipulate our biology to benefit themselves and us should provide new insights about the foundations of our health and new therapeutic strategies for preventing or treating various diseases."
According to Gordon, in order to develop a comprehensive view of humans as a lifeform, we need to consider the fact that the human body is home to diverse communities of microorganisms from birth to death. It is estimated that adults are composed of 10 times more microbial cells than human cells.
The intestine harbors our largest collection of microbes. Although the true extent of biodiversity is not known, it appears that the gut contains at least 1,000 different species of bacteria, and that their collective genomes ('the microbiome') contains 100-fold more genes than the human genome. These bacteria provide certain metabolic capabilities that humans lack, including the ability to process nutrients that human genes cannot break down.
Gordon's team analyzed Bacteroides thetaiotaomicron as a representative of this microbial community because it is such a prominent member.
"This bacterium becomes prominent beginning at a key developmental transition that takes place when infants are weaned
Contact: Gila Z. Reckess
Washington University School of Medicine