Segmented genomes abound in the RNA virus world. They are found in virus particles from different families, and can be double stranded (Reoviridae) or single stranded of (+) (Closteroviridae) or (-) (Orthomyxoviridae) polarity. Our recent discussion of the advantages of a segmented viral genome, compared with monopartitie genomes, generated a good discussion. Another interesting question concerns the evolutionary relationship between the two genome types. Did monopartite viral genomes emerge first, then later fragmented to form segmented genomes? Some recent experiments provide insight into this question.