Personal Professor, School of Public Health, University of the Witwatersrand, South Africa
Senior Scientist, MRC/Wits Rural Public Health and Heath Transitions Research Unit (Agincourt), School of Public Health, University of the Witwatersrand, South Africa

Project Site Manager, MRC/Wits Rural Public Health and Heath Transitions Research Unit (Agincourt), School of Public Health, University of the Witwatersrand, South Africa

Professor of Neuropsychology (in Neurology, the Gertrude H. Sergievsky Center and the Taub Institute for Research on Alzheimer's Disease and the Aging Brain), Columbia University

Postdoctoral Research Fellow, Brigham and Women's Hospital

Professor in Human Genetics, National Health Laboratory, University of the Witwatersrand (Wits), Johannesburg, South Africa
Director of the Sydney Brenner Institute for Molecular Bioscience, University of the Witwatersrand (Wits), Johannesburg, South Africa
South African Research Chair (Bioinformatics and Genomics of African Populations), University of the Witwatersrand (Wits), Johannesburg, South Africa

Research Scientist, Harvard Center for Population and Development Studies
Project Director, HAALSA