DNA purification is a typical and important procedure in molecular biology. Purification of DNA is targeted at separation of the desired genetic material (chromosomal material) from other contaminants, such as proteins, RNA, and cell membrane. This is a crucial procedure in nearly every molecular application and must be done correctly in order to get high-quality, usable DNA.
There are a variety of options for DNA purification. The choice is based on a variety of factors such as the starting materials and downstream applications, as well as cost and time limitations. The typical genomic and plasmid purification protocols require chemical treatment, enzymatic digestion or mechanical destruction of cells and tissues, followed by salting out proteins and precipitating DNA using alcohol.
Ethanol precipitation is a cost-effective, quick and simple method of desalting and concentrating DNA. DNA molecules form aggregates in the presence of monovalent cations like sodium, and are then filtered out of solution using high levels of ethanol. This method is employed to remove salts, organic compounds, and other impurities. It is commonly used with other purification methods.
Anion exchange chromatography is another well-known method for DNA purification. The interaction between the negatively-charged DNA phosphate phosphate backbones, as well as the positively-charged surface molecules of resins bonds DNA in a solvent to positively charged resins. During the binding process the contaminants are removed making use of a strict washing process. The DNA purified is eluted using low-salt conditions.
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