Editing DNA extraction (section)

==Detection of DNA==
{{main|Quantification of nucleic acids}}

A [[Diphenylamine|diphenylamine (DPA) indicator]] will confirm the presence of DNA. This procedure involves chemical hydrolysis of DNA: when heated (e.g. ≥95&nbsp;°C) in acid, the reaction requires a [[Deoxyribose|deoxyribose sugar]] and therefore is specific for DNA. Under these conditions, the 2-deoxyribose is converted to w-hydroxylevulinyl aldehyde, which reacts with the compound, diphenylamine, to produce a blue-colored compound. DNA concentration can be determined by  measuring the intensity of absorbance of the solution at the 600&nbsp;nm with a [[spectrophotometer]] and comparing to a [[standard curve]] of known DNA concentrations.

Measuring the intensity of absorbance of the DNA solution at wavelengths [[Quantification of nucleic acids|260 nm and 280 nm]] is used as a measure of DNA purity. DNA can be quantified by cutting the DNA with a [[restriction enzyme]], running it on an agarose [[gel electrophoresis|gel]], staining with [[ethidium bromide|ethidium bromide (EtBr)]] or a different stain and comparing the intensity of the DNA with a DNA marker of known concentration.

Using the [[Southern blot]] technique, this quantified DNA can be isolated and examined further using [[Polymerase chain reaction|PCR]] and [[RFLP]] analysis. These procedures allow differentiation of the repeated sequences within the genome. It is these techniques which [[forensic]] scientists use for comparison, identification, and analysis.