1. Department of Genome Sciences, University of Washington, Seattle, WA 98195, USA.
2. Department of Immunology, University of Washington, Seattle, WA 98109, USA.
3. Benaroya Research Institute, Seattle, WA 98101, USA.
4. Agilent Technologies, Santa Clara, CA 95051, USA.
5. Department of Medicine, University of Washington, Seattle, WA 98195, USA.