Cistron

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cistron

[′sis‚trän]

(cell and molecular biology)

The genetic unit (deoxyribonucleic acid fragment) that codes for a particular polypeptide; mutants do not complement each other within a cistron. Also known as structural gene.

The following article is from The Great Soviet Encyclopedia (1979). It might be outdated or ideologically biased.

Cistron

a unit of genetic material responsible for a single function. The term “cistron” was introduced by the American geneticist S. Benzer in 1957 together with the terms “recon”—the smallest unit of deoxyribonucleic acid (DNA) capable of recombination—and “muton”—the smallest unit of DNA in which a change can result in a mutation. Benzer hypothesized correctly that all three units are sections of the nucleic acid molecule that differ from one another in length. In size the cistron is equal on the average to 1,200 nucleotides, with the number of nucleotides generally varying from 400 to 4,000. In modern genetics, a cistron is generally defined as the unit in nucleic acid that codes the structure of a single polypeptide. Consequently, the terms “cistron” and “gene” are synonymous.

REFERENCE

Fiziologicheskaia genetika. Leningrad, 1976.

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References in periodicals archive ?

In the cytotype C1, major ribosomal DNA cistrons are located in the terminal position of the short arms of the first metacentric as determined by silver nitrate impregnation (Figure lb) and FISH with the 18S rDNA probe (data not shown).

Karyotype and nucleolus organizer regions of Ophisternon aenigmaticum (Teleostei: Synbranchiformes: Synbranchidae)/ from Venezuela/Cariotipo y regiones de organizadores nucleolares de Ophisternon aenigmaticum (Teleostei: Synbranchiformes: Synbranchidae) de Venezuela ..

The concomitant use of 18S and 5S rDNA probes, using the FISH technique, showed the 18S ribosomal cistrons in a pair of subtelocentric chromosomes, on the long arm in the terminal position (Figure 1b) and the 5S sites were found in another subtelocentric pair, on the long arm in the interstitial region, near the centromere (Figure 1b).

Cytogenetic analysis of the 18S, 5S rDNA and B chromosome of Iheringichthys labrosus (Lutken, 1874) (Siluriformes, Pimelodidae)/Analise citogenetica de DNAr 18S, 5S e cromossomo B de Iheringichthys labrosus (Lutken, 1874) (Siluriformes, Pimelodidae)

FISH detection of ribosomal cistrons and assortment-distortion for X and B chromosomes in Dichroplus pratensis (Acrididae).

110 years of orthopteran cytogenetics, the chromosomal evolutionary viewpoint, and Michael White's signal contributions to the field

He argues that the gene is best understood not as a single protein sequence (or cistron) at a single locus on a chromosome, responsible for the synthesis of a single protein chain, but as a retroactively identified "cause" of any given phenotypic effect: