Identification of an R-locus region that controls the tissue specificity of anthocyanin formation in maize

The R locus in maize controls the tissue specificity of anthocyanin formation. Recombination between two different R-locus alleles with unique pigmentation domains has resulted in the generation of a nonparental allelic type that displays a third kind of tissue specificity. These novel changes in tissue specificity occurred in very low frequency (1 x 10^-5). In light of this finding and of recent results concerning the regulation by R of the enzyme UDPG: flavonoid 3-0-glucosyltransferase, specified by the B_z locus, a model dealing with the genetic control of tissue-specific functions in multicellular organisms is proposed.