Jeff performs research on mitochondrial replacement therapy in the Biomedicine Discovery Institute. Previously, he led laboratories researching the role of epigenetics in mammalian germ cell development at the City of Hope National Medical Center in Los Angeles, The University of Melbourne, and the Murdoch Children’s Research Institute, Melbourne. For several years he instructed the 'Molecular Embryology of the Mouse Course' at the Cold Spring Harbor Laboratory, New York, and has directed institutional facilities for making preclinical models of disease.