Central Dogma: Replication, Transcription, Translation

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  • DNA contains the complete genetic information that defines the structure and function of an organism.
  • Proteins are formed using the genetic code of the DNA.
  • Conversion of DNA encoded information to RNA is essential to form proteins.
  • Thus, within most cells, the genetic information flows from – DNA to RNA to protein.
  • The flow of information is followed through three different processes which are responsible for the inheritance of genetic information and for its conversion from one form to another.
The Central Dogma
The Central Dogma
  1. Replication: a double stranded nucleic acid is duplicated to give identical copies. This process perpetuates the genetic information.
  2. Transcription: a DNA segment that constitutes a gene is read and transcribed into a single stranded sequence of RNA. The RNA moves from the nucleus into the cytoplasm.
  3. Translation: the RNA sequence is translated into a sequence of amino acids as the protein is formed. During translation, the ribosome reads three bases (a codon) at a time from the RNA and translates them into one amino acid.
  • This flow of information is unidirectional and irreversible.
Central Dogma- Replication, Transcription, Translation

This explanation is the simplest way in which the Central Dogma of Molecular Biology is interpreted.

  • In the bigger picture, the central dogma of molecular biology is an explanation of the flow of genetic information within a biological system.
  • It was first stated by Francis Crick in 1958, as
    • “Once ‘information’ has passed into protein it cannot get out again. In more detail, the transfer of information from nucleic acid to nucleic acid or from nucleic acid to protein may be possible, but transfer from protein to protein, or from protein to nucleic acid is impossible.”

The Dogmas

  • The dogma is a framework for understanding the transfer of sequence information between information-carrying biopolymers, DNA and RNA (both nucleic acids), and protein.
  • There are 3×3=9 conceivable direct transfers of information that can occur between these.
  • The dogma classes these into 3 groups of 3:

A. Three general transfers

  • It describes the normal flow of biological information: DNA can be copied to DNA (DNA replication), DNA information can be copied into mRNA (transcription), and proteins can be synthesized using the information in mRNA as a template (translation).
  • It is believed to occur normally in most cells.

B. Three special transfers

  • The special transfers describe: RNA being copied from RNA (RNA replication), DNA being synthesised using an RNA template (reverse transcription), and proteins being synthesised directly from a DNA template without the use of mRNA.
  • Temin (1970) reported the existence of an enzyme “RNA dependent DNA polymerase” (inverse transcriptase) which could synthesize DNA from a single stranded RNA template.
  • Baltimore (1970) also reported the activity of this enzyme in certain RNA tumour viruses.
  • This exciting finding in molecular biology gave rise to the concept of central dogma reverse” or teminism, suggesting that the sequence of information flow is not necessarily from DNA to RNA to protein but can also take place from RNA to DNA.
  • It is known to occur, but only under specific conditions in case of some viruses or in a laboratory.

C. Three unknown transfers

  • The unknown transfers describe: a protein being copied from a protein, synthesis of RNA using the primary structure of a protein as a template, and DNA synthesis using the primary structure of a protein as a template
  • These are not thought to naturally occur.

Significance of the Central Dogma of Molecular Biology

Thus, the central dogma provides the basic framework for how genetic information flows from a DNA sequence to a protein product inside cells and thus give an insight to the important processes going on inside the cells.

References

  1. Verma, P. S., & Agrawal, V. K. (2006). Cell Biology, Genetics, Molecular Biology, Evolution & Ecology (1 ed.). S .Chand and company Ltd.
  2. https://users.ugent.be/~avierstr/pdf/principles.pdf
  3. http://www.csun.edu/~cmalone/pdf360/Ch14-1gen%20code.pdf
  4. https://en.wikipedia.org/wiki/Central_dogma_of_molecular_biology.

About Author

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Sagar Aryal, PhD

Dr. Sagar Aryal is a microbiologist, researcher, and science communicator from Nepal. He is also co-founder and Research Head of the Department of Natural Products at the Kathmandu Research Institute for Biological Sciences (KRIBS), where he leads research on natural product discovery and microbial biodiversity. Dr. Aryal earned his Ph.D. in Microbiology from Tribhuvan University, Kathmandu, Nepal, in 2025, supported by a DAAD Research Grant and a University Grants Commission (UGC) Nepal Ph.D. Fellowship. His research interests include Actinomycetes, Myxobacteria, microbial taxonomy, and natural products, particularly the discovery of bioactive compounds with potential pharmaceutical applications. He isolated and identified Nocardia nepalensis, a novel bacterial species from Nepal, contributing to understanding microbial diversity in the region. Dr. Aryal has published more than 16 research articles in international journals and contributed three book chapters to established academic publications. He has presented scientific research findings and developed international research collaborations through visits to more than 18 countries across Asia, Europe, North America, and Oceania. From 2023 to 2025, he served as the American Society for Microbiology (ASM) Young Ambassador to Nepal. Since December 2025, he has served as an Editorial Board Member of Scientific Reports, a Nature Portfolio journal. In recognition of his scientific contributions, Dr. Aryal received the NAST Science and Technology Youth Award 2025 from the Nepal Academy of Science and Technology. He previously received the Frs. Locke and Stiller Research Award (LSRA) for the 2017-2018 cycle from St. Xavier's College, Kathmandu, and a Nepal Academy of Science and Technology (NAST) Research Grant for 2017-2018. Alongside his scientific career, Dr. Aryal has more than 15 years of experience in blogging, content writing, and search engine optimization (SEO).