Different segments of the polytene chromosomes resulted in a differential banding after staining with a mixture of DAPI and propidiumiodid (DAPI/PI)(see figure).
Areas of euchromatin showed in dark blue, while centromeric and telomeric heterochromatin displayed a pink color. Especially striking were the white bands inside the pink colored cHC of some chromosomes. Their position corresponded to the strong DAPI bands. In this way the strong DAPI bands could not only distingished easily because of their greater brightness, but also because of their color, significantly different from the rest of the cHC.