1. Duke University Program in Genetics and Genomics; Department of Biology; Duke University; Durham NC 27708 USA
2. Department of Biology; Howard Hughes Medical Institute; Curriculum in Genetics and Molecular Biology; Carolina Center for Genome Sciences; University of North Carolina; Chapel Hill NC 27599 USA
3. Joint Genome Institute; Walnut Creek CA 94598 USA
4. Department of Microbiology and Immunology; Carolina Center for Genome Sciences; University of North Carolina; Chapel Hill NC 27599 USA
5. Department of Biology; Institute for Genome Sciences & Policy; Duke University; Durham NC 27708 USA