Detection of barley chromatin added to wheat by genomic in situ hybridization

A technique for in situ hybridization is reported that can be used to detect barley chromatin in wheat background using total genomic DNA as a probe. A 1:2 ratio of biotin-labeled genomic DNA of barley to blocking (unlabeled, sheared) DNA of wheat was sufficient to reveal brownish labeled barley chromosome domains against bluish background of unlabeled wheat chromatin in metaphase, prophase, and interphase nuclei of wheat-barley addition lines. Using this procedure, the behavior of specific barley chromosomes was analyzed in interphase and prophase cells. In prophase cells, the 6H chromosome was always associated with a nucleolus. A genomic clone of α-amylase gene (gRAmy56) that contains a barley-specific dispersed repeat sequence was also used to detect barley chromosomes in a wheat background.