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Pronunciation: sis'tron


  1. The smallest functional unit of heritability; a length of chromosomal DNA associated with a single biochemical function. Under classical concepts, a gene might consist of more than one cistron; in modern molecular biology, the cistron is essentially equivalent to the structural gene.
  2. The genetic unit defined by the cis/trans test.

[cis tr-ans + -on]

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© Copyright 2018 Wolters Kluwer. All Rights Reserved. Review date: Sep 19, 2016.