The ‘Central Dogma’ is the process by which the instructions in DNA are converted into a functional product. It was first proposed in 1958 by Francis Crick, discoverer of the structure of DNA.
- The central dogma of molecular biology explains the flow of genetic information, from DNA to RNA, to make a functional product, a protein.
- The central dogma suggests that DNA contains the information needed to make all of our proteins, and that RNA is a messenger that carries this information to the ribosomes.
- The ribosomes serve as factories in the cell where the information is ‘translated’ from a code into the functional product.
- The process by which the DNA instructions are converted into the functional product is called gene expression.
- Gene expression has two key stages – transcription and translation.
- In transcription, the information in the DNA of every cell is converted into small, portable RNA messages.
- During translation, these messages travel from where the DNA is in the cell nucleus to the ribosomes where they are ‘read’ to make specific proteins.
- The central dogma states that the pattern of information that occurs most frequently in our cells is:
- From existing DNA to make new DNA (DNA replication)
- From DNA to make new RNA (transcription)
- From RNA to make new proteins (translation).
An illustration showing the flow of information between DNA, RNA and protein.
Image credit: Genome Research Limited
- Reverse transcription is the transfer of information from RNA to make new DNA, this occurs in the case of retroviruses, such as HIV. It is the process by which the genetic information from RNA is assembled into new DNA.
Does the ‘Central Dogma’ always apply?
- With modern research it is becoming clear that some aspects of the central dogma are not entirely accurate.
- Current research is focusing on investigating the function of non-coding RNA.
- Although this does not follow the central dogma it still has a functional role in the cell.
This page was last updated on 2021-07-21
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Most genes contain the information needed to make functional molecules called proteins. (A few genes produce regulatory molecules that help the cell assemble proteins.) The journey from gene to protein is complex and tightly controlled within each cell. It consists of two major steps: transcription and translation. Together, transcription and translation are known as gene expression.
During the process of transcription, the information stored in a gene's DNA is passed to a similar molecule called RNA (ribonucleic acid) in the cell nucleus. Both RNA and DNA are made up of a chain of building blocks called nucleotides, but they have slightly different chemical properties. The type of RNA that contains the information for making a protein is called messenger RNA (mRNA) because it carries the information, or message, from the DNA out of the nucleus into the cytoplasm.
Translation, the second step in getting from a gene to a protein, takes place in the cytoplasm. The mRNA interacts with a specialized complex called a ribosome, which "reads" the sequence of mRNA nucleotides. Each sequence of three nucleotides, called a codon, usually codes for one particular amino acid. (Amino acids are the building blocks of proteins.) A type of RNA called transfer RNA (tRNA) assembles the protein, one amino acid at a time. Protein assembly continues until the ribosome encounters a “stop” codon (a sequence of three nucleotides that does not code for an amino acid).
The flow of information from DNA to RNA to proteins is one of the fundamental principles of molecular biology. It is so important that it is sometimes called the “central dogma.”