It is important to have high-quality DNA that is free of contaminants like protein, debris and RNA prior to performing a PCR, cloning, or DNA sequencing. The process of purifying DNA is referred to as DNA isolation and is one of the most important steps in molecular biology. This article will explain the fundamentals of DNA extraction and how to optimize it for better results.
The first step in the process of purifying DNA is to prepare a solution that includes a mix of water and an alkaline buffer. This buffer makes DNA soluble and it is easy to separate from other components in the sample. After the DNA is placed in an alkaline solution and a water solution, it is treated with detergents and Chaotropics salts to more information break down the cell membranes and nuclei. This releases the DNA. RNase can be added to the sample to remove any DNA contamination.
DNA is separated from other cellular components such as proteins and lipids 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 quality of the DNA can then be confirmed using spectrophotometry, or gel electrophoresis. A good quality DNA sample should have an absorbance ratio between 220 nm to 280 nm.