Which virus families have double-stranded DNA in four different isomers?
The herpesvirus has double-stranded linear DNA, which is unusual because it has terminal and internal repeated sequences. The DNA of some of its members (e.g., herpes simplex viruses) can undergo genetic rearrangement, which results in four different genomic isomers. In an isomer, there is the same molecular formula but different arrangement. The DNA of herpesviruses is large (molecular weight = 90-150 x 106), encoding at least 100 proteins. There is little sequence homology in the DNA among the various members of the family (30% to 50%), Except between herpes simplex virus types 1 and 2 and between human herpes 6 and 7. Morphologically, however, they are indistinguishable. The nucleocapsid of herpesviruses has icosahedral symmetry. The lipid envelope, which is derived from the nuclear membrane of the infected cell during budding, contains viral glycoproteins. The area between the capsid and the envelope is the tegument, and it contains several viral proteins. Poxviruses have double-stranded, linear DNA. Rabies viruses, ohomyxoviruses (influenza), and retroviruses have single-stranded, linear RNA. Ref : Ananthanarayana textbook of Microbiology 9th edition Pgno : 467
Poxviruses
Herpesviruses
Rabiesviruses
Ohomyxoviruses
Virology