[Electron microscopic in situ hybridization of dUTP-digoxigenin labeled probes with polytene chromosomes of Drosophila melanogaster].

Using DNA probes labeled with digoxygenin-11-dUTP, a simplified method of electron microscopic (EM) in situ hybridization was developed for standard squashes of Drosophila melanogaster polytene chromosomes. The developed method is efficient and reproducible: its high resolution and specificity was shown for the transformed strain 148, in which the insertion was localized by EM as a new thin band. The method was applied for fine mapping of the developmentally regulated complex gene, muscleblind (mbl), which was shown to cover the 54B1-2 large band and the adjacent interbands in 2R polytene chromosome.