1. Neurobiology-Neurodegeneration & Repair Laboratory (N-NRL), National Eye Institute, National Institutes of Health, Bethesda, Maryland, 20892;
2. On leave of absence from Departments of Ophthalmology and Human Genetics, University of Michigan, Ann Arbor, Michigan 48109
3. Division of Epidemiology and Clinical Applications, National Eye Institute, National Institutes of Health, Bethesda, Maryland, 20892
4. Departments of Ophthalmology and Cell Biology, Duke University Medical Center, Durham, North Carolina, 27710
5. Center for Statistical Genetics, Department of Biostatistics, University of Michigan, Ann Arbor, Michigan 48109