1. Departments of Medicine and Microbiology, University of Alabama at Birmingham
2. Department of Psychology, University of Pennsylvania, Philadelphia, Pennsylvania 19104
3. Institute of Genetics, University of Nottingham, Queens Medical Centre, Nottingham NH7 2UH, United Kingdom
4. Ethologie des Primates, Centre Ecologie, Physiologie et Ethologie (CNRS UPR 9010) and Université Louis Pasteur, Strasbourg, France
5. Laboratoire Retrovirus, UMR036, Institut de Recherche pour le Developement and Department of International Health, University of Montpellier I, Montpellier, France
6. Howard Hughes Medical Institute, Birmingham, Alabama 35294