cistron
Học thuậtThân thiện
Definition
Noun: * In genetics, a cistron is a segment of DNA that codes for a specific polypeptide chain (a protein or part of a protein). It is the functional unit of heredity, encompassing not only the coding sequences (exons) but also the regulatory regions and non-coding intervening sequences (introns). Historically, the term was used to define a gene based on its function in a specific test.
Examples
- Noun:
- The scientist mapped the specific cistron responsible for the enzyme's production.
- Mutations within this cistron can lead to a loss of protein function.
- In classical genetics, a cistron was defined operationally by the complementation test.
Advanced Usage
- The term cistron is largely synonymous with the modern molecular definition of a gene, especially when referring to a protein-coding sequence. It emphasizes the gene as a functional unit.
- It is used to distinguish a functional genetic unit from a mutational or recombination unit (a muton or recon, respectively).
Variants and Related Words
- Gene (n): The more common modern term for the fundamental physical and functional unit of heredity. While often used interchangeably with cistron, "gene" can have broader connotations.
- Exon (n): The coding segments of a cistron or gene that are expressed in the final protein product.
- Intron (n): The non-coding intervening sequences within a cistron or gene that are removed during RNA processing.
Synonyms
- Gene
- Genetic factor (historical)
- Hereditary unit
Related Phrases
- Cistron map: A genetic map showing the location and order of cistrons.
- Polycistronic mRNA: A single messenger RNA molecule that encodes multiple proteins (multiple cistrons), common in prokaryotes.
Noun
- (genetics) a segment of DNA that is involved in producing a polypeptide chain; it can include regions preceding and following the coding DNA as well as introns between the exons; it is considered a unit of heredity
- genes were formerly called factors