Jonathan Weitzman is professor of genetics at the Universite Paris-Diderot, a founding director of the Centre Epigenetique et Destin Cellulaire, and a former faculty member at the Pasteur Institute, Paris. The research unit he founded and directs develops expertise in epigenetic mechanisms in stem cells and cellular differentiation.Mathew Weitzman is associate professor in the Department of Pathology & Laboratory Medicine of the University of Pennsylvania Perelman School of Medicine. His lab studies the intersection between virus infection and mechanisms that maintain genome integrity. He has authored over 80 research articles and reviews, and he serves on the editorial boards of several international journals.Jonathan & Matthew are identical twins.