Central dogma

Definition

The principle that genetic information flows unidirectionally from DNA to RNA to protein, with sequence information transferable between nucleic acids or from nucleic acid to protein, but not from protein to nucleic acid or between proteins. Originally formulated by Francis Crick in 1957, it describes the irreversibility of information transfer once encoded in amino-acid sequence.

Etymology

Coined by Francis Crick in 1957; 'dogma' used ironically to denote a fundamental principle rather than a doctrinal belief

Example

In Drosophila melanogaster, the central dogma explains why a mutation in the white gene (DNA) is transcribed into altered white mRNA, which is translated into a defective ABC transporter protein affecting eye pigment deposition; the phenotypic change cannot be reverse-transcribed back to correct the original DNA lesion.

Related Terms

• Transcription
• translation
• reverse transcription
• Gene expression
• messenger RNA
• Ribosome
• Genetic code
• epigenetics

Usage Notes

Often misquoted as 'DNA→RNA→protein'; Crick's original formulation emphasized the irreversibility of information flow, not merely the sequence. The discovery of reverse transcriptases (RNA→DNA) and prions (protein→protein conformation transfer) modify but do not invalidate the core principle regarding sequence information. In arthropod molecular ecology, the dogma underlies why mitochondrial DNA sequences are preferred for phylogeography while nuclear transcripts reveal functional adaptation.