This lecture covers the genetic code expansion method, focusing on site-specific incorporation of non-native amino acids in living systems using fruit fly models. It explains the amber suppression method, biocompatible click chemistry, and the power of GAL4/UAS system for targeted gene expression. The lecture also discusses the significance of animal models in research, with a spotlight on Drosophila melanogaster. Various advanced concepts such as proteome labeling, protein identification, and tissue-specific proteome labeling in fruit flies are explored.