cis arrangement

(coupling) The situation in which an individual is heterozygous for two linked *genes (either two units of function or two mutations in the same functional unit), and one chromosome carries both the recessive (or mutant)  alleles.  The homologous chromosome thus carries both the dominant (or normal) alleles and will mask the effects of the recessives in the phenotype. Compare trans arrangement. See also cis-trans test.