An unusual wheat insertion sequence (WIS1) lies upstream of an alpha-amylase gene in hexaploid wheat, and carries a "minisatellite" array.
Comparison of the 5' flanking regions of three alpha-amylase genes from chromosome 6B of hexaploid wheat by heteroduplex and sequence analysis revealed the presence of a 1.6 kb stem-loop insertion sequence (WIS1) in one of them. Polymorphism among hexaploid wheat varieties suggests the relatively recent insertion/excision of this sequence from its present position. The complete sequence of the stem-loop insertion shows that it has many of the features found in transposable elements, including target site duplication and terminal inverted repeats. One unusual feature is a tandem array of direct repeats comprising a wheat "minisatellite" sequence. Both the insertion sequence and the minisatellite are found at multiple locations in the wheat genome, but the functional significance of their association in WIS1 is unknown. The minisatellite arrays share a common core structure, and long arrays are polymorphic between different hexaploid varieties.
Martienssen
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Institute of Plant Science Research (Cambridge Laboratory), UK.
Baulcombe
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D001483:Base Sequence; D004251:DNA Transposable Elements; D004276:DNA, Satellite / Q000235:genetics; D008969:Molecular Sequence Data; D005810:Multigene Family; D010944:Plants / Q000235:genetics*; D011110:Polymorphism, Genetic; D011123:Polyploidy; D012091:Repetitive Sequences, Nucleic Acid; D015183:Restriction Mapping; D012689:Sequence Homology, Nucleic Acid; D014908:Triticum / Q000235:genetics; D000516:alpha-Amylases / Q000235:genetics*
D004251:DNA Transposable Elements; D004276:DNA, Satellite; D000516:alpha-Amylases