TABLE 1-2.

Structure of the Genome in Viruses of Different Familiesa^a

Family	Structure of nucleic acid
Papovaviridae	Circular superhelical dsDNA (see Plate 1-2)
Adenoviridae	Linear dsDNA with inverted terminal repeats and a covalently bound protein (see Fig. 1-3A)
Herpesviridae	Linear dsDNA; two unique sequences flanked by reiterated sequences; isomeric configurations occur (see Fig. 1-3B)
	Linear dsDNA; both ends covalently closed, with inverted terminal repeats (see Fig. 1-3C)
Parvoviridae	Linear ssDNA, (–) sense; with repeated sequences and a hairpin structure at one end (see Fig. 1-3D)
Hepadnaviridae	Circular dsDNA with ss region
	Linear ssRNA, (+) sense; serves as mRNA; 3’ end polyadenylated (except Flaviviridae); 5’ end capped, or protein covalently bound (Picornaviridae, Caliciviridae)
	Linear ssRNA, (–) sense
Rhabdoviridae
Orthomyxoviridae	Segmented genome; 7 or 8 molecules of linear ssRNA, (–) sense
Arenaviridae	Segmented genome; 2 molecules of ssRNA, (–) sense or ambisenseb; “sticky ends” allow circularization
Bunyaviridae	Segmented genome; 3 molecules of ssRNA, (–) sense or ambisense; “sticky ends” allow circularization
Retroviridae	Diploid genome, dimer of linear ssRNA, (+) sense; hydrogen bonded at 5’ ends; terminal redundancy; both 3’ termini polyadenylated, both 5’ ends capped; may carry oncogene
Reoviridae	Segmented genome; 10, 11, or 12 molecules of linear dsRNA
Birnaviridae	Segmented genome; 2 molecules of linear dsRNA

^aThere is considerable variation within some families, e.g., Herpesviridae, Reoviridae.

^bAmbisense indicates that part of molecule is (+) and part (–) sense.