| 1988 |
Committee of the Public Affairs Office of the Ecological Society of America on environmental applications of genetically engineered organisms |
| 1988-1989 |
National Research Council Committee on Scientific Evaluation of the Introduction of Genetically Modified Microorganisms and Plants into the Environment |
| 1989-1997 |
Associate Editor, Theoretical Population Biology |
| 1990-1992 |
Associate Editor, Evolution |
| 1990-1996 |
National Research Council Commission on Life Sciences |
| 1990-1996 |
National Research Council Board on Biology |
| 1991-1993 |
Editorial Board, Microbial Ecology |
| 1991-1999 |
Editorial Advisory Board, Molecular Ecology |
| 1994 |
National Science Foundation Population Biology Review Panel |
| 1995 |
Vice-chair, Gordon Research Conference on "Population Biology and Evolution of Microbes and their Accessory Elements" |
| 1995-1998 |
Editorial Board, The American Naturalist |
| 1996-1998 |
Council Member, Society for the Study of Evolution |
| 1997 |
Co-chair, National Research Council Workshop on "Ecology and Evolution of Infectious Diseases" |
| 1999 |
Visiting Professor for Workshop on Experimental Evolution of Bacteria, Center for Population Biology, University of California, Davis |
| 1999 |
Visiting Professor for Summer Workshop on Evolutionary Biology, University of Basel, Switzerland |