1. Graduate Program in Organismic and Evolutionary Biology, University of Massachusetts Amherst, Amherst, Massachusetts, USA
2. Department of Energy, Joint Genome Institute, Berkeley, California, USA
3. Centre for Microbiology and Environmental Systems Science, Department of Microbiology and Ecosystem Science, Division of Microbial Ecology, University of Vienna, Vienna, Austria
4. Department of Biological Sciences, Smith College, Northampton, Massachusetts, USA
5. Department of Biology, University of Massachusetts Amherst, Amherst, Massachusetts, USA