We attempted to perform differential staining of chromosomes. The cells were pre-incubated with EdU for 6 hours and then treated with nocodazole for 1.5 hours. Detection was carried out using click chemistry with biotin-azide. Then, the cells were incubated with streptavidin-HRP, followed by the addition of DAB substrates and hydrogen peroxide. We expected to see chromosome banding, but the staining occurred along the contours of the chromosomes. Could you please help interpret the results? Perhaps someone has encountered a similar issue?