In this talk, we will explore the evolution of novel functions in animals, with a focus on toxins in venomous bees and snakes. We will base our discussion on a combination of genomic and proteomic data, as well as tools such as synteny, phylogenetic and protein space AI analyses that were used to investigate the origin and diversification of toxin-encoding genes. We will delve into the mechanisms of gene duplication and its relationship to the emergence of novel biological functions, illustrating it by the evolution of g2 family of phospholipase A2 in Vertebrata and the 3-finger toxins in caenophidian snakes. Our reconstruction of evolutionary history suggests that duplication events and the resulting functional redundancy have played a significant role in the evolution of these gene families. However, our research also highlights that the evolution of functionally diverse genes is a complex process that is shaped by a variety of historical, genomic, and ecological factors, and that neofunctionalization may not always be the best model to explain the evolution of genetic novelty.