PRE-ANNEALING OF TOTAL GENOMIC DNA PROBES FOR SIMULTANEOUS GENOMIC IN-SITU HYBRIDIZATION

We used pre-annealing of differently labelled total genomic DNA probes to perform simultaneous genomic in situ hybridization on mitotic and meiotic chromosomes of interspecific hybrids between plant species of the Tribe Triticeae. The species origin of chromosomes was demonstrate d by a two-colour fluorescence after in situ hybridization with direct ly labelled probes incorporating fluorescein (visualized green) and rh odamine (visualized red). The pre-annealing blocked out common DNA seq uences between the different genomes, hence increasing species specifi city of the probes. The method is simple and rapid because the hybridi zation takes only about 2 h, including the pre-annealing step, and hen ce the whole process can be accomplished easily within a working day m aking it suitable for routine analysis of chromosomes and genomes.