Differential fluorescent staining of Drosophila chromosomes with quinacrine mustard

The polytene and mitotic chromosomes of D. melanogaster, D. simulans, D. ananassae , and D. virilis were stained with the fluorescent dye, quinacrine mustard (QM). In all these species except D. ananassae , we have detected species-specific chromosomal loci which exhibit an extremely brilliant fluorescence. Most, but not all, of the brilliantly fluorescing areas are located in heterochromatic chromosome regions. Cytochemical and chemical methods have been employed to demonstrate that the brilliant fluorescence represents regions of acid labile non-covalent binding between DNA and QM whereas the moderate overall fluorescence is primarily due to covalent bonding (by alkylation) of the QM to DNA. The exact mode of binding of QM in the brilliant areas and the nature of the DNA in these areas are not known. The possible biological significance of the DNA in the brilliant regions is discussed.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/47355/1/412_2004_Article_BF00285186.pd