Universite Lille-Nord de France 1 article published in JoVE Biology The Tomato/GFP-FLP/FRT Method for Live Imaging of Mosaic Adult Drosophila Photoreceptor Cells Pierre Dourlen1,2, Clemence Levet1, Alexandre Mejat1, Alexis Gambis3, Bertrand Mollereau1 1Laboratory of Molecular Biology of the Cell, Ecole Normale Supérieure de Lyon, 2INSERM U744, Institut Pasteur de Lille, Université Lille-Nord de France, 3Howard Hughes Medical Institute, Laboratory of Apoptosis and Cancer, The Rockefeller University The Tomato/GFP-FLP/FRT method involves visualizing mosaic photoreceptor cells in living Drosophila. It can be used to follow individual photoreceptor cell fates in the retina for days or weeks. This method is ideal for studies of retinal degeneration and neurodegenerative diseases or photoreceptor cell development.