Different Methods for DNA Purification
DNA purification is one of the most commonly used and crucial processes in molecular science. The purpose of DNA purification is to isolate the desired genetic material from the contaminant (proteins, cell membranes and RNA). This is a vital step in almost every molecular procedure and must be performed well in order to produce the highest quality usable DNA.
There are a number of different methods available for DNA purification, the choice of which is based on a variety of factors, including the starting materials and downstream applications and costs and time constraints. Typical genomic and plasmid DNA purification protocols include chemical treatment, enzymatic digestion, or mechanical disruption of tissue/cell samples followed by salting-out the proteins and precipitation of the DNA using alcohol.
Ethanol precipitation is a cost-effective simple and quick method of desalting and concentrating DNA. DNA molecules accumulate in the presence of monovalent cations like sodium, and are then precipitated from the solution using high concentrations ethanol. This method is employed to remove salts, organic compounds, and other impurities. It is often used with other purification methods.
Anion exchange is another popular method for DNA purification. DNA in a solution is bound to positively charged resins via the interaction between the negatively charged DNA phosphate backbone and the positively charged surface molecules of the resin. During the binding and washing processes, contaminating molecules are removed from the DNA using strict washing steps, and the DNA purified is eluted using low salt conditions.