H. Chan School of Public Health, Boston, Massachusetts, USA, with a secondary appointment in the Department of Biostatistics. He is an associate member of the Program in Medical and Population Genetics at the Broad Institute of MIT and Harvard, Cambridge, Massachusetts, USA. His research focuses on the development of statistical methods for uncovering the genetic basis of human disease, and on the population genetics underlying these methods. Areas of interest include functional components of heritability, common versus rare variant architectures, and disease mapping in structured populations.