APP and Alzheimer disease: During the last decade, several studies have employed Drosophila as a model to study AD using one of two approaches; either the Aβ peptides are fused to a secretion sequence and directly produced from transgenes or the Aβ peptides are produced by the processing of human AβPP (Caesar et al., 2012; Chakraborty et al., 2011; Mhatre et al., 2014).