In this episode, I speak to Rob Knight, an assistant professor in the Department of Chemistry and Biochemistry at the University of Colorado, Boulder.

Knight studies our inner ecology: the 100 trillion microbes that grow in and on our bodies. Knight explained how hundreds of species can coexist on the palm of your hand, how bacteria manipulate your immune system and maybe even your brain, and how obesity and other health problems may come down to the wrong balance of microbes.

Links to studies mentioned in this episode: Ruth Ley and Peter Turnbaugh's studies on obesity in Jeff Gordon's lab: Obesity alters gut microbial ecology. Microbial ecology: human gut microbes associated with obesity. An obesity-associated gut microbiome with increased capacity for energy harvest. A core gut microbiome in obese and lean twins. Julie Segre's studies of the skin: A diversity profile of the human skin microbiota. Topographical and temporal diversity of the human skin microbiome. Chris Lauber and Elizabeth Costello's studies of human-associated body habitats (in Noah Fierer's and Rob Knight's lab): The influence of sex, handedness, and washing on the diversity of hand surface bacteria. Bacterial community variation in human body habitats across space and time. Jeremy Nicholson's studies of the metabolome: Pharmacometabonomic identification of a significant host-microbiome metabolic interaction affecting human drug metabolism. Cathy Lozupone's study of global microbial diversity (in Rob Knight's lab), and confirmation of the patterns in archaea by Jean-Christophe Auguet: Global patterns in bacterial diversity. Global ecological patterns in uncultured Archaea. Ruth Ley and Cathy Lozupone's study integrating gut-associated and environmental bacteria:

Worlds within worlds: evolution of the vertebrate gut microbiota.