1. Department of Computer Science, University of Colorado at Boulder Boulder Colorado 80309
2. Department of Chemistry and Biochemistry, University of Colorado at Boulder Boulder Colorado 80309
3. Department of Molecular, Cellular and Developmental Biology, Yale University New Haven Connecticut 06511
4. Department of Ecology and Evolutionary Biology, University of Colorado at Boulder Boulder Colorado 80309
5. Division of Allergy and Clinical Immunology, Department of Medicine, University of Colorado Anschutz Medical Campus Aurora Colorado 80045
6. Howard Hughes Medical Institute Boulder Colorado 80309 USA