Inheritance and Organization of Glycinin Genes in Soybean.
Five genes (Gy1, through Gy5) encode most of the subunits that are assembled into glycinin, a predominant seed storage protein found in soybeans. Restriction fragment length polymorphisms are described that identify four of these five genes (Gy1/Gy2, Gy3, and Gy5). The fifth gene (Gy4) is characterized by two alleles, one of which (gy4) causes absence of the subunit. Genetic segregation studies indicate that the five genes are located at four genetic loci within the genome. Gy1 and Gy2 are in a direct tandem repeat at one locus, whereas there is a single glycinin gene at each of the other three loci. All four loci segregate independently from one another, and they also segregate independently from the genetic markers for tawny/grey pubescence (T/t), purple/white flower color (W1/w1), light/dark hilum pigmentation (l/ll), black/brown seed coat (R/r), and brown/tan pod color (I1I1L2L2/I1I1I2I2). The latter genetic markers are located on linkage groups 1 (t), 8 (w1), 7 (i), and 2 (r) in the soybean genome, respectively.