We have expressed AD-related genes such as UAS-TauWT, UAS- Aβ42(Human) and UAS-ApplRNAi in the eyes of flies using pan-retinal GMR-GAL4 [GMR-GAL4-UAS-TauWT/+, GMR-GAL4-UAS-Aβ42(Human)/+ and GMR-GAL4/+;UAS-ApplRNAi/+] and expressed other AD genes such as UAS-Aβ42E693G and UAS-APP.C99-UAS-MAPT in the neurons using pan-neuronal elav-Gal4C155 (elav-Gal4C155/+;+/+;UAS-Aβ42E693G/+ and elav-Gal4C155/+;+/+;UAS-APP.C99-UAS-MAPT/+). The gene discussed is MAPT; the disease is Alzheimer disease.