n. the section of a DNA or RNA chain that controls the amino-acid sequence of a single polypeptide chain in protein synthesis. A cistron can be regarded as the functional equivalent of a *gene.
n. the basic unit of genetic material, which is carried at a particular place on a *chromosome. Originally it was regarded as the unit of inheritance and mutation but is now usually defined as a sequence of *DNA or *RNA that acts as the unit controlling the formation of a single polypeptide chain (see cistron). In diploid organisms, including humans, genes occur as pairs of *alleles. Various kinds of gene have been discovered: structural genes determine the biochemical makeup of the proteins; regulator genes control the rate of protein production (see operon). Architectural genes are responsible for the integration of the protein into the structure of the cell, and temporal genes control the time and place of action of the other genes and largely control the *differentiation of the cells and tissues of the body.... gene
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