Gene duplication is one of the main drivers of evolution. It is well-known that copies arising from duplication can undergo multiple evolutionary fates, but little is known on their relative frequency, and on how environmental conditions affect it. In this paper we provide a general framework to characterize the fate of duplicated genes and formally differentiate the different fates. To test our framework, we simulate the evolution of populations using aevol, an in silico experimental evolution platform. When classifying the resulting duplications, we observe several patterns that, in addi-1 2 1 INTRODUCTION tion to confirming previous studies, exhibit new tendencies that may open up new avenues to better understand the role of duplications.