Q.Name any three viruses which have RNA as the genetic material.

Three viruses whose genetic material is RNA rather than DNA:

• Tobacco Mosaic Virus (TMV) — a plant virus, and the classic textbook example of an RNA-genome virus; it carries single-stranded RNA that also acts directly as messenger RNA.
• Qβ (Q-beta) bacteriophage — a bacterial virus (infects E. coli), the other RNA-genome virus specifically named alongside TMV.
• HIV (Human Immunodeficiency Virus) — a retrovirus whose RNA genome is reverse-transcribed into DNA inside the host cell before it is expressed. …

The story of genetic material is not just about DNA. While DNA is the hereditary molecule in most organisms, a class of viruses stores its genetic information as RNA instead.

Tobacco Mosaic Virus (TMV) infects tobacco and related plants, producing the mottled "mosaic" leaf pattern that gives it its name. Its genome is single-stranded RNA that can act directly as messenger RNA once inside a host cell.

Qβ bacteriophage infects Escherichia coli. Like TMV, it carries a single-stranded RNA genome — it is the second example used alongside TMV when introducing the idea that RNA, not just DNA, can serve as genetic material.

HIV (Human Immunodeficiency Virus), the cause of AIDS, is a retrovirus: its RNA genome is converted into DNA inside the host cell by the enzyme reverse transcriptase, and this DNA copy then integrates into the host genome. HIV shows that an RNA genome does not prevent a virus from eventually being expressed via a DNA intermediate. …

Instead of naming three unrelated viruses, sort by how the RNA genome gets used once inside the host: TMV's RNA is read directly as if it were mRNA; Qβ bacteriophage's RNA is likewise used directly inside a bacterial host; HIV's RNA must first be reverse-transcribed into DNA before anything can be expressed …