DNA purification is a common and crucial procedure in molecular biology. The purpose of DNA purification is the separation of the desired genetic material from contaminants (proteins, cell membranes, and RNA). This is a crucial step in almost every molecular application and must be done correctly in order to obtain high-quality and usable DNA.
There are a variety of options for DNA purification. The choice is based on a range of factors such as the starting materials and downstream applications, costs and time limitations. The standard genomic and plasmid purification methods include chemical treatment, enzyme digestion or mechanical destruction of cells or tissues and then salting out the proteins and precipitating the DNA using alcohol.
Ethanol precipitation is a simple cheap and fast method for desalting and concentrating DNA. DNA molecules aggregate in the presence monovalent cations like sodium, and then they are removed from solution using high concentrations ethanol. This technique permits the removal of organic compounds and other impurities from a sample and is often employed in conjunction with other purification techniques.
Another method that is popular for DNA purification is anion exchange chromatography. DNA in solution is linked to positively charged resins through 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 by stringent wash steps and the purified DNA is eluted in low salt conditions.