The α-gliadin gene family. I. Characterization of ten new wheat α-gliadin genomic clones, evidence for limited sequence conservation of flanking DNA, and Southern analysis of the gene family
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A detailed study of the organization of the wheat α-gliadin gene family is described. In the first stage of this study recombinant libraries of sufficient size and quality were constructed to allow examination of large, closely-related, gene families. A large number of α-gliadin clones were then isolated in a partial screen of these libraries. A set of these clones were sequenced and ten new gene sequences are now reported. Including these new sequences, 20 of the 27 known α-gliadin genomic and cDNA sequences are from cv Cheyenne, making this cultivar the best studied for gliadin family organization. An analysis of the DNA flanking the coding regions shows divergences which may indicate the functional ends of the α-gliadin genes. High-resolution Southern analyses on DNA from aneuploid and chromosome-substitution lines allow most of the 20 distinct α-gliadin HindIII restriction fragments in cvs Cheyenne and Chinese Spring to be assigned to specific genomes. It is estimated that as many as 150 α-gliadin genes occur in the cultivar Cheyenne, and the limitations of such estimates are discussed.
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