DNA extraction is a routine procedure to collect DNA for subsequent molecular or forensic analysis. There are three basic steps in a DNA extraction:
1. Breaking the cells open to expose the DNA within, such as by grinding or sonicating the sample.
2. Removing membrane lipids by adding a detergent.
3. Precipitating the DNA with an alcohol — usually ethanol or isopropanol. Since DNA is insoluble in these alcohols, it will aggregate together, giving a pellet on centrifugation. This step also removes alcohol-soluble salt.