TAXONOMY OF BACTERIAL-VIRUSES - ESTABLISHMENT OF TAILED VIRUS GENERA AND THE ORDER CAUDOVIRALES

Bacterial viruses have been classified into 13 families and I unassign ed genus. A new order, Caudovirales, has now been established, compris ing the three families of tailed bacterial viruses, based on similarit ies in tailed virus morphology, replication, and assembly. In addition , genera have been established for some species in each tailed virus f amily, based on properties involving viral DNA replication and packagi ng, and on some features specific to particular genera (e.g., DNA-term ini linked proteins, virus-encoded polymerases, and ability to establi sh temperate infections). At present, there are six genera in the fami ly Myoviridae (viruses with contractile tails), six in the family Siph oviridae (viruses with long, noncontractile tails), and three in the f amily Podoviridae (viruses with short noncontractile tails). In recogn ition that the definitions of tailed virus genera represent a ''work i n progress'' and to keep the nomenclature flexible, tailed virus gener a have been assigned vernacular names based on their type species.