1. From the Divisons of Basic Sciences and Human Biology, Fred Hutchinson Cancer Research Center, Seattle, WA (Peichel); Phase Genomics, Inc., Seattle, WA (Sullivan and Liachko); and Department of Genetics, University of Georgia, 120 Green Street, Athens, GA 30602 (White). Catherine L. Peichel is now at the Institute of Ecology and Evolution, University of Bern, 3012 Bern, Switzerland.