Which color indicates a positive result for DNA in the diphenylamine test?

The diphenylamine test is a chemical assay used to detect the presence of DNA. In this test, the reagent diphenylamine reacts with the deoxyribose sugar present in DNA, resulting in a color change. A positive result, characterized by a color change to blue or purple, indicates that DNA is present in the sample being tested. This color reaction occurs because the diphenylamine forms a complex with the DNA, which leads to the formation of the colored compounds. The intensity of the color can be indicative of the amount of DNA present, making this test a valuable tool in various biological and forensic applications. Therefore, blue or purple is the correct indication of a positive result for DNA in the diphenylamine test.