Before conducting an PCR reaction, cloning experiment or DNA sequencing, it is essential to have high-quality DNA which is free of contaminants like debris, proteins and RNA. Purifying DNA is also referred as DNA Isolation and is a crucial step in molecular biology. In this article you will discover the fundamentals of DNA purification, and how to improve your DNA extraction processes to get better results.
The initial step in the DNA purification procedure is to prepare a solution that contains a mixture consisting of water and alkaline buffer. This buffer makes the DNA soluble so that it will easily separate from other components of the sample. Once the DNA has been placed in an alkaline and water solution, it’s then treated by chaotropic salts or detergents to destroy cell membranes and nuclei and release DNA (cell lysis). RNase can also be added to remove any contaminants in the RNA sample.
DNA is separated from other cellular components like proteins and lipids by using organic solvents such as chloroform and phenol. After the DNA has been removed from proteins and lipids it can be precipitated using ethanol or isopropyl alcohol (rubbing alcohol).
Spectrophotometry and gel electrophoresis can be used to determine the quality of DNA. A good quality sample of DNA should have an absorbance range of 220 nm to 280 nm.