ABSTRACT
DNA is a genetic material and the basic hereditary unit of each and every cell. DNA isolation is the process of purification of DNA by using a combination of physical and chemical methods. DNA was first isolated in 1869 by Friedrich Miescher. The purification of nucleic acids broadly involves the following steps: breaking or opening of cells to expose nucleic acids, separation of nucleic acids from other cellular components, and recovery of nucleic acids in pure form. The nucleic acid absorbs light strongly in the UV region at 260 nm due to the conjugated bond present in purine and pyrimidine bases. DNA concentration is measured using a double cell UV spectrophotometer. To extract DNA from tissue/cell of interest, the cells have to be separated, and cell membranes have to be extracted by an extraction buffer. DNA is concentrated by mostly ethanol precipitation. In the presence of salt, ethanol efficiently precipitates polymeric nucleic acid.
