Text Text METHODS References Viruses modulate ecosystems by directly altering host metabolisms through auxiliary metabolic genes, which are obtained through random sampling of the host genome and rise to fixation, presumably through improved viral fitness by alleviating key metabolic bottlenecks during infection. Conspicuously, however, viral genomes are not known to encode the core components of translation machinery, such as ribosomal proteins (RPs), though genes for RPs S1 and S21 have been detected in viral metagenomes1,2. Here we augment this little-noticed observation using available reference genomes, global-scale viral metagenomic datasets, and functional assays for select proteins. We identify 15 different RPs across diverse viral genomes arising from cultivated viral isolates (5 RPs in 16 genomes) and metag ...