Question

State the ‘Central dogma’ as proposed by Francis Crick. Are there any exceptions to it? Support your answer with a reason and an example.

Answer 1

Francis Crick proposed the ‘Central dogma’, which states that genetic information within a cell flows from DNA to RNA through transcription and from RNA to proteins through translation.

However, there are some exceptions to this process. In some viruses, the genetic material is in the form of RNA. In such cases, the direction of this information flow is reversed. The RNA is first converted into DNA through the process of reverse transcription. The DNA thus formed follows the usual path of the central dogma, i.e. it first converts into RNA, which is then translated into proteins. RNA tumour viruses (oncogenic) and HIV Ill virus (Virus causing AIDS) are good examples of retroviruses.