Dr. Kelsey’s research has centered on the development and application of biomarkers useful for population-based studies. His group was among the first to use genomic approaches to ask questions about how the biological effects of environmental exposures are modified by normal genetic variation. His laboratory has also been among the first to extend genetic investigations into studies of epigenetics and modifications of the expression of important genetic changes. His current research interest is focused on deepening our understanding of the potential environmental contributors to alterations of the immune system.