James Turner began his undergraduate studies in medicine at Queen Mary, University of London, during which he acquired an intercalated BSc in biochemistry. He subsequently transferred to UCL (University College London) in order to join the MB PhD course. He did his PhD at the Medical Research Council National Institute for Medical Research (NIMR) with Paul Burgoyne, studying how sex chromosome abnormalities cause infertility.
He later completed his medical training and briefly practiced as a clinician at West Hertfordshire NHS Trust. He then returned to Paul Burgoyne's lab to continue his studies on sex chromosome genetics as a postdoctoral scientist.
After a sabbatical in the USA, James set up his own research group at the NIMR in 2007 (now part of the Francis Crick Institute) and was awarded tenure in 2012. His work currently focuses on the evolution and epigenetics of X chromosome inactivation, and the role of the X chromosome in germ cell development.