Preparation of Chromosome Spreads by Root-Tip Meristem Dissection for In Situ Hybridization with Biotin-Labeled Probes

Success with hybridization of DNA sequences in situ to plant chromosomes depends on many factors, but of foremost importance is the quality of the chromosome preparation. If this is not of high standard in terms of the number of metaphases achieved and the cleanliness of the background, there is really little point proceeding with the time-consuming and expensive process of the in situ hybridization procedure. There are several methods of making good chromosome preparations suitable for in situ (e.g., see chapter 24 ). The one described here has the advantage of simplicity, requiring little in terms of equipment and materials, but it does need patience and dexterity at least in the first attempts, after which the procedure soon becomes routine.