The Metaviridae, Pseudoviridae, and Belpaoviridae are the three families of eukaryotic reverse-transcribing viruses with Long Terminal Repeats (LTRs), popularly known as Ty3/Gypsy, Ty1/Copia, and Bel/Pao LTR retrotransposons, respectively. The three families are unified into the order Ortervirales together with members of the families Retroviridae and Caulimoviridae which infect vertebrates and plants, respectively. Here, we review the molecular biology and diversity of metaviruses, pseudoviruses and belpaoviruses. We explore the similarities and evolutionary relationships among them as well as with other members of the Ortervirales based on life cycle, sequence, architecture of genes and other features. Their host range and impact on the biology and evolution of eukaryotes is also discussed.

Fourth Edition.

Peer reviewed