It is vital to have high quality DNA that is free of contaminants like proteins, debris and RNA prior to carrying out the PCR as well as cloning or DNA sequencing. The process of purifying DNA is known as DNA isolation, and is one of the most important steps in molecular biology. In this article you will discover 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 comprises a mixture of water and an alkaline buffer. This buffer makes DNA soluble, which means it can be easily separated from other components in the sample. After the DNA is placed in a water and alkaline solution, it is then treated with detergents or chaotropic salts to destroy cell membranes and nuclei to release DNA (cell lysis). RNase is also added to eliminate any contamination RNA from the sample.

The DNA is separated by organic solvents such as chloroform or phenol from other components of the cell such as proteins and fats. After the DNA is separated from proteins and lipids, it is able to be extracted using ethanol or isopropyl alcohol (rubbing alcohol).

The purity of the DNA may be verified using spectrophotometry or gel electrophoresis. A good quality DNA sample should have an absorbance at 260 nm to 282 nm. 1.8. A low ratio could indicate an issue with the protein binding step or the transfer of salt from the bind or wash buffers.