n :  a segment of DNA that is equivalent to a gene and that specifies a single functional unit (as a protein or enzyme) and within which two heterozygous and closely linked recessive mutations are expressed in the phenotype when on different chromosomes but not when on the same chromosome - compare MUTON RECON  cis*tron*ic adj 
 
 
 
Similar sounding terms:  cis·tern  cis·ter·na 
 
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