PhEVER is the first open access database to provide information at the cross-taxa scale for the analysis of virus-virus and virus-host protein transfers. It compiles information from all kingdoms of life, and handles data from the genomes of all completely sequenced viruses and prokaryotes and of a large range of eukaryotes. It is the largest database of viral homologous families and offers highly accurate pre-computed alignments and phylogenies, making it a powerful tool for the analysis of horizontal gene transfer and more widely for the analysis of gene history. Our objective is to continue the development of PhEVER around the analysis of protein evolution in the context of virus-virus and virus-host interactions. More specifically, the next step we have under development is the detection of evolutionary conserved modules in the proteins present in PhEVER. Indeed, there is strong evidence that proteins evolve in a modular way, where modules are defined as parts of proteins sharing a common evolutionary history. These modules act as small interchangeable blocks of sequences that may be combined into proteins and form novel functions (33) (34) (35) . We are interested in providing a global tool allowing to analyse the weight of modular evolution in viral adaptation. We will therefore implement the detection of modules in PhEVER proteins to provide information concerning the exchanges of genetic information at the sub-protein level.