Biotechnology and Bioinformatics (1+1)

1.2.2.2. Genes made of RNA

Most genetic systems studied to date contain genes made of DNA. But some viruses , including several phages, plant and animal viruses (e.g., HIV, the AIDS virus), have RNA genes. Sometimes viral RNA genes are double-stranded but usually they are single-stranded.

A group of viruses, referred to as retrovirus es, has RNA as the genetic material. These tumour viruses can integrate with the host genome DNA, only after the RNA makes a DNA copy. Thus, these viruses carry the gene for reverse transcriptase catalyses the conversion of RNA to DNA.

The central dogma says that the flow of information is unidirectional i.e. DNA → RNA → Protein .

With the discovery of the enzyme reverse transcriptase, it is now clear that RNA can also go back to DNA and the central dogma is now represented as: RNA → DNA → Protein.