 In chromosomes after DNA replication, each of the two daughter chromatids had one DNA molecule running its length.He revealed this structure by examining amphibian lampbrush chromosomes in the microscope after staining for DNA and for RNA and also after treatment with enzymes that break down DNA or RNA.Although the Feulgen stain for DNA was not sensitive enough to stain the DNA in the loops of these chromosomes, but only stained the long axis of the structure, the loops were sensitive to DNase so they must contain DNA that maintained their loop structure.