It is crucial to have a high-quality DNA that is free of contaminants such as protein, debris and RNA prior to carrying out a PCR, cloning, or DNA sequencing. Purifying DNA is also known as DNA Isolation, and is an essential step in molecular biology. This article will explain the basics of DNA extraction and how to optimize it to achieve better results.
The first step of the process of purifying DNA is to prepare a solution which comprises a mixture of water and an alkaline buffer. This buffer makes the DNA soluble, so that it can easily be separated from the other components of the sample. Once the DNA is in an alkaline and water solution, it is then treated with detergents or chaotropic salts to destroy cell membranes and nuclei, and release the DNA (cell lysis). RNase can be added to the sample in order to remove any DNA contamination.
DNA is separated from other cellular components such as proteins and lipids by using organic solvents such as chloroform and phenol. After the DNA is separated from lipids or proteins it is then precipitated using alcohol or ruby alcohol.
The purity of the DNA can be determined by spectrophotometry or gel electrophoresis. A high-quality sample of DNA should have an absorbance range of 220 nm to 280 nm.