DNA Purification Methods

A high-quality sample of DNA is required for a variety of downstream applications like PCR and sequence. DNA purification is the process of eliminating contaminants like proteins and other cellular components, from a sample in order to create an uncontaminated nucleic acid solution ready for use. There are a variety of DNA purification methods to choose from, each having distinct advantages and disadvantages dependent on the source material and the purpose for which it is intended to be used.

The first step in DNA purification is to remove proteins from the sample using the proteinase (protein enzyme) or mechanical disruption. After the cellular debris is eliminated, DNA can be precipitated using alcohol to form a white, stringy precipitate. The DNA that is precipitated can be resuspended, either in water or a sterile solution. The concentration of DNA can be determined using the spectrophotometry method based on the nucleic acid absorbance peak at 260nm.

Another popular method for DNA purification is salting out. In this method, a cellulose column is utilized to capture and bind the DNA. The cellulose matrix is cleaned using detergents to get rid of contaminants, and washing buffers are used to flush out the salts. DNA binds to matrix under low salt conditions and the proteins and RNA can be washed away with higher salt solutions. The eluted RNA and DNA are then recovered with the ethanol precipitation.

Anion exchange chromatography why not look here can also be a popular technique for DNA purification. This method utilizes a cation-exchange resin to attract positively charged DNA molecules, while a neutralizing resin allows negatively-charged DNA to be removed of the column. After the DNA has been extracted it can be concentrated using centrifugation. The DNA can be precipitated out by washing with 70 percent ethanol in ice-cold temperatures.