PRIMER-MEDIATED IN-SITU DETECTION OF THE B-HORDEIN GENE-CLUSTER ON BARLEY CHROMOSOME 1H

In situ hybridization methods allow the detection of specific DNA sequ ences on whole chromosomes. The technique has been widely used as a di agnostic and research tool by animal cytogeneticists, for whom detecti on of unique sequences on mammalian chromosomes is routinely achieved. However, detection of unique sequences on plant chromosomes is less r eliable. The recently developed primer-induced in situ hybridization ( PRINS) technique allows rapid and reliable in situ detection by the hy bridization of primers to denatured target DNA, followed by extension with DNA polymerase in the presence of a labeled nucleotide. The use o f short oligonucleotide primers could allow improved penetration of de bris and highly condensed chromatin common in preparations of plant ch romosomes, thus increasing the sensitivity of in situ detection. The f easibility of this approach is demonstrated by the oligonucleotide pri mer-mediated detection of the B-hordein gene cluster on a barley chrom osome. Applications of the PRINS technique for plant cytogeneticists a re discussed.