cis

cis /cis / (sis) [L.]

1. in organic chemistry, having certain atoms or radicals on the same side.

2. in genetics, denoting two or more loci, especially pseudoalleles, occurring on the same chromosome of a homologous pair. Cf. . See also cis-trans test, under test.

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cis (ss)

adj.

Having two mutations on two genes on the same chromosome of a homologous pair.

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cis,

pref Latin preposition meaning “on this side.” In stereochemistry, it refers to the position of carbon chains extending from a molecule.

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cis

[L.] in organic chemistry, having certain atoms or radicals on the same side; in genetics, having the two mutant genes of a pseudoallele on the same chromosome. Compare trans. See also cis-transtest.

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cis acting

in molecular biology, a sequence or regulatory protein that is part of the same DNA molecule as the gene of interest. See also trans acting.

cis-acting mutation

in the lactose operon a mutation in the attenuator region that disrupts base pairing in the double-stranded portion of the termination hair pin and permits the RNA polymerase to 'read through' the termination signal.

cis-dominant mutation

occurs in regulatory sequences that are recognized by DNA binding proteins that affect only adjacent genes on the same DNA molecule.