Question

What are the four forms of viral genomes?

Answer 1

An enormous amount of genomic structures can be seen among viral species.

Explanation:

A virus has either a DNA or RNA genome. Plant viruses tend to have single stranded RNA genomes and bacteriophages have double stranded DNA genome.

Viruses can be grouped into families depending upon the type of genome and their method of replication. This system of classification was developed by David Baltimore and contains the following 7 categories.

1) Double stranded DNA viruses
e.g. Herpesviruses.

2) Single stranded DNA viruses
e.g. Geminiviridae

3) Double stranded RNA viruses
e.g. Reoviridae

4) Single stranded RNA viruses ( positive sense ).
e.g. Astroviridae

5) Single stranded RNA viruses ( negative sense ).
e.g. Paramyxoviridae

6) Positive sense single stranded RNA viruses that replicate through a DNA intermediate.
e.g. Retroviruses

7) Double stranded DNA viruses that replicate through a single stranded RNA intermediate.
e.g. Hepadnaviridae.