1. Stem Cell Biology Unit/Laboratory of Neurosciences, National Institute on Aging Intramural Research Program, National Institutes of Health, Baltimore, MD 21224.
2. Waisman Center, University of Wisconsin, Madison, WI 53705.
3. Solexa, Inc., Hayward, CA 94545.
4. Corporate Research Laboratories, Invitrogen Corporation, Carlsbad, CA 92008.
5. Johns Hopkins School of Medicine, Baltimore, MD 21287.