Moderately repeated, dispersed, and highly variable (MRDHV) genomic sequences of common wheat usable for cultivar...

A 4.1-kb DNA clone (pTag546), which when used as a probe produces hypervariable DNA fingerprints in common wheat, was found among the genomic clones of Triticum aestivum cv 'Chinese Spring'. Nulli-tetrasomic analyses revealed that the sequences hybridizing to this clone were located at 12 loci on ten chromosomes of the A, B, and D genomes of common wheat. The complete nucleotide sequence of pTag546 was shown to have a transposable element-like structure within it, though no open reading frame was detected. The sequences located in the A and D genomes were assumed to have been derived from the B genome by transposition. Using this clone as a probe, we were able to identify 56 common wheat cultivars, some of which are closely related, by their DNA fingerprints. This suggests that pTag 546 will be useful for cultivar identification as well as for germ plasm evaluation in wheat.