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Medical Dictionary


adj \ˈsis\

Medical Definition of CIS

:  characterized by having certain atoms or groups of atoms on the same side of the longitudinal axis of a double bond or of the plane of a ring in a molecule
:  relating to or being an arrangement of two very closely linked genes in the heterozygous condition in which both mutant alleles are on one chromosome and both wild-type alleles are on the homologous chromosome—compare trans 2
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