The chromosomal locations and linkage relationships of the structural genes for the prolamin storage proteins (secalins) of rye

Rye secalins are a polymorphic mixture of polypeptides which are classified into four major groups. Previous studies have shown that the structural genes for two of the groups (the ω-secalins and 40K γ-secalins) are located on the short arm of chromosome 1R and those for a third group (the high molecular weight secalins) on the long arm of the same chromosome. Analysis of F2 grain from crosses between inbred lines of S. cereale shows that the structural genes for the ω-secalins (designated Sec 1) and the high molecular weight secalins (designated Sec 3) are loosely linked (40.8 ±3.76% recombination, 57.4 ± 11.30 cM). Analysis of wheat rye addition lines shows that the structural genes for the 75K γ-secalins are present on chromosome 2R. This locus is provisionally designated Sec 2. These genes are probably derived from those for the 40K γ-secalins by duplication, divergence and translocation. Analysis of secalin fractions from wild species of rye shows that all contain 75K γ-secalins, indicating that the duplication and divergence, if not the translocation, occurred before speciation of the genus.