Paramutation in Corn

• B-I alleles encodes an enzyme in the pathway of anthocyanin pigments.
• b alleles lack these pigment and are recessive to B-I.
• B' is the paramutagenic allele and only makes a small amount anthocyanin pigment.
• Crosses between B' and B-I give lightly pigmented plants indicating that B' is dominant to B-I
• Crosses of these heterozygotes should give 1/4 pigmented plants but only give lightly pigmented plants.
• The B-I allele is said to be paramutated.
• By being in the same genotype as B' for one generation the B-I allele has been disabled by the B' allele