DNA purification is a common and important procedure in molecular biology. Purification of DNA is targeted at getting rid of the desired genetic material (chromosomal material) from other contaminants, such as proteins, RNA, and cell membrane. This is a vital procedure in almost every molecular process and must be executed correctly in order to obtain the highest quality usable DNA.
There are many different methods available for DNA purification, the selection of which depends on several aspects, including the materials used to start and downstream applications, as well as cost and time constraints. The most common DNA purification procedures include chemical treatment, enzymatic digestion, or mechanical disintegration of samples of cells or tissues followed by salting-out of the proteins and the precipitation of DNA using ethanol.
Ethanol precipitation can be a low-cost easy and quick method of desalting and concentrating DNA. DNA molecules are aggregated in the presence of monovalent cations, such as sodium and are then precipitated from the solution using high concentrations ethanol. This method is used to remove organic compounds, and other impurities. It is often employed in conjunction with other purification methods.
Another popular method for DNA purification is anion exchange chromatography. DNA in a solution is bonded to positively charged resins due to the interaction between the negatively charged DNA phosphate backbone http://www.mpsciences.com/2021/04/15/gene-synthesis-and-transcription-processes/ as well as the positively charged surface molecules of the resin. During the binding and washing steps the contaminating molecules are removed from the DNA by stringent wash steps. The purified DNA is eluted in low salt conditions.