1. University of Wisconsin—Madison, Department of Medical Microbiology and Immunology, Madison, Wisconsin, USA
2. University of Connecticut, Department of Molecular and Cell Biology, Storrs, Connecticut, USA
3. University of Connecticut, Institute for Systems Genomics, Storrs, Connecticut, USA
4. University of Michigan Medical School, Department of Microbiology and Immunology, Ann Arbor, Michigan, USA
5. University of Oregon, Institute of Molecular Biology, Eugene, Oregon, USA
6. Humans and the Microbiome Program, Canadian Institute for Advanced Research, Toronto, Ontario, Canada