1. The Institute for Genomic Research, 9712 Medical Center Drive, Rockville, MD 20850, USA.
2. Stanford Genome Technology Center, Stanford University, 855 California Avenue, Palo Alto, CA 94304, USA.
3. Neurobiology Sector, International School for Advanced Studies (SISSA-ISAS), Via Beirut 2-4, 34014 Trieste, Italy.
4. Department of Molecular Genetics and Microbiology, Duke University Medical Center, 322 CARL Building, Research Drive, Box 3546, DUMC, Durham, NC 27710, USA.
5. Genome Sciences Centre, 100-570 West 7th Avenue, Vancouver, BC V5Z 4S6, Canada.