GENETIC-MAPPING OF THE GY4 AND GY5 GLYCININ GENES IN SOYBEAN AND THE ANALYSIS OF A VARIANT OF GY4

The predominant storage protein of soybean [Glycine max (L.) Merr.] se ed is a globulin called glycinin. Thus far five genes encoding glycini n subunits have been described, and these are denoted by the gene symb ols Gy1 to Gy5. The objectives of this study were to map two of these genes, Gy4 and Gy5, and to conduct a genetic analysis of a subunit siz e-variant from an allele of Gy4. For this purpose a population was for med with an interspecific cross between PI468916 (G. soja) and A81-356 022 (G. max). The two size forms of G4, the subunit from Gy4, segregat ed codominantly in the mapping population, and were due to a short ins ertion in the hypervariable region of the mutant protein. The biochemi cal and molecular characteristics of the two subunits indicate that th ey are produced from alternate alleles of the same gene. The gene symb ols Gy(a) and Gy(b) have been assigned to the normal and variant genes , respectively. When genomic DNA from the two parents was probed with a Gy4 cDNA, RFLPs were identified for both Gy4 and Gy5. Using these ge netic markers, the Gy4 and Gy5 glycinin genes were mapped in linkage g roup ''O'' and ''F'' on the public soybean genomic map.