Central dogma
Say it: SEN-trul DOG-muh
The central dogma is the principle that genetic information flows from DNA into RNA and then into protein, and never back from protein into nucleic acid.
Definition
What is the central dogma?
The central dogma of molecular biology describes how genetic information moves within cells. DNA is copied into new DNA during replication, a gene's DNA is transcribed into messenger RNA, and ribosomes translate that RNA into the amino acid sequence of a protein. Francis Crick first stated the idea in 1958, and it remains the basic framework for understanding how genes produce traits.
Its key claim concerns direction. Sequence information can pass from nucleic acid to protein, but once it is in a protein it cannot flow back into DNA or RNA, because cells have no machinery to read a protein's sequence and write it into a nucleic acid. The dogma does not forbid transfers between nucleic acids, and some occur: retroviruses such as HIV use reverse transcriptase to copy RNA into DNA, and many RNA viruses copy RNA directly into RNA. Prions, infectious proteins that spread a misfolded shape, are sometimes cited as an exception, although they pass on structure rather than sequence.
The scheme is a simplification. Many genes are never translated and instead make working RNAs such as transfer RNA, ribosomal RNA and microRNA, and every step from gene to protein is regulated.
Word parts
Where does the term “central dogma” come from?
- dogma
- opinion, belief; something held as settledGreek dogma, from dokein (to seem, to think)
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Terms that go with it
- TranscriptionTranscription is the process in which a cell copies the DNA sequence of a gene into a matching strand of RNA.
- TranslationTranslation is the process in which a ribosome reads the codons of a messenger RNA and links amino acids in that order to build a protein.
- DNA replicationDNA replication is how a cell copies all of its DNA before it divides, so that each daughter cell receives a complete genome.
- Messenger RNAMessenger RNA is the RNA copy of a gene that carries protein-building instructions from DNA to the ribosomes, where it is read in three-base codons.
- Reverse transcriptaseReverse transcriptase is an enzyme that builds DNA from an RNA template, letting retroviruses such as HIV turn their RNA genome into DNA.
- Gene expressionGene expression is the use of a gene's information to make a working product, usually a protein or a functional RNA molecule.
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Checked against
Written for biofideX in plain words, after checking these references:
- NHGRI Talking Glossary: Central Dogma
- OpenStax Biology 2e, 15.1 The Genetic Code
- MedlinePlus Genetics: How do genes direct the production of proteins?
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