|Group:||Group IV ((+)ssRNA)|
- conserved RNA-dependent RNA polymerase
- genome has a protein attached to the 5' end
- no overlapping open reading frames within the genome
- all the RNAs are translated into a polyprotein before processing
The evolution of these viruses may have preceded the separation of eukaryotes into the extant crown groups.
The taxonomy of this group has been reorganised by the ICTV in 2011. The Caliciviridae and the Potyviridae have been removed from this order. The Bacillariornaviridae, the Labyrnaviridae, and the Sequiviridae have been reduced to genera.
- Le Gall O, Christian P, Fauquet CM, King AM, Knowles NJ, Nakashima N, Stanway G, Gorbalenya AE "Picornavirales, a proposed order of positive-sense single-stranded RNA viruses with a pseudo-T = 3 virion architecture." Arch Virol. 2008;153(4):715–27
- Koonin EV, Wolf YI, Nagasaki K, Dolja VV (2008) The Big Bang of picorna-like virus evolution antedates the radiation of eukaryotic supergroups. Nat Rev Microbiol. 6(12):925–939