- Organic Extraction
When phenol or a mixture of phenol:chloroform is mixed with a cell Lysate, two phases form: an aqueous and an organic phase. The polar DNA partitions into the polar or “aqueous phase”, and denatured proteins and other cellular debris partition into the organic phase.
- Salting Out
Salts are thought to dehydrate proteins, causing them to become less hydrophilic and are subsequently denatured. The denatured proteins lose solubility and precipitate; precipitated proteins and cellular debris are removed by centrifugation. Salts typically used in these protocols include sodium, potassium acetate or ammonium.
- Bind to Solid Support
Most modern DNA purification methods are based on purification of DNA from crude lysates by selective binding to a support material. These support materials include silica-based supports and anion-exchange resins. Generally these methods are quicker and more convenient than other methods because they do not require any organic solvents and can be miniaturized and automated for high throughput.