Before doing any PCR reaction, cloning experiment or DNA sequencing it is critical to have a high-quality DNA that is free of contaminants, such as debris, protein and RNA. The process of purifying DNA is referred to as DNA isolation. It is one of the most vital steps in molecular biology. In this article, you will be taught the fundamentals of DNA purification and how you can optimize your DNA extraction strategies to get better results.
The first step of the DNA purification process is to prepare a solution which contains a mixture of water and an alkaline buffer. This buffer makes DNA soluble and it is easily separated from other components in the sample. After the DNA has been placed in an alkaline and water solution, it is treated with detergents and chaotropics salts to break up the cell membranes and nuclei. This allows the DNA to be released. RNase can also be added to eliminate any contaminants in the RNA sample.
The DNA is then separated by organic solvents such as phenol or chloroform from other cellular components, such as fats and proteins. After the DNA is removed from the proteins or lipids it is then precipitated using alcohol or rubbing alcohol.
Spectrophotometry and gel electrophoresis can be used to determine the purity of DNA. A good quality DNA sample should have a ratio of absorbance at 260 nm to the range of 280 nm.