The Basics of DNA Purification

Before performing the PCR reaction or cloning test or DNA sequencing, it’s essential to have high-quality DNA that is free of contaminants like debris, protein and RNA. The process of purifying DNA is known as DNA isolation. It is one of the most important steps in molecular biology. In this article you will be taught the fundamentals of DNA purification, and how to improve your DNA extraction processes to get better results.

The first step of the process of purifying DNA is to prepare a solution that is composed of water and an alkaline buffer. This buffer makes the DNA more soluble so that it can easily be separated from other components of the sample. Once the DNA has been placed in an alkaline and water solution, it’s treated with detergents and salts that break down the cell membranes and nuclei. This releases the DNA. RNase can be added into the sample to remove any contaminating DNA.

The DNA is then separated by organic solvents, such as phenol or chloroform from other cellular components like fats and proteins. After the DNA has been removed from lipids or proteins then it can be precipitated using ethanol or ruby alcohol.

The quality of the DNA sample can be verified using spectrophotometry or gel electrophoresis. A good quality DNA sample must have a ratio of absorbance between 260 and the range of 280 nm. 1.8. A low ratio may indicate a problem with the protein binding process or the transfer of salt from wash or bind buffers.