How Does DNA Precipitation Work?
One must first understand why nucleic acids are soluble in water. Water (H2O) is a polar molecule that has a partial negative charge near the oxygen atom due the unshared pairs of electrons, and partial positive charges near the hydrogen atoms. Due to this polar nature of water, other polar molecules such as DNA or RNA can interact electrostatically with the water molecules, allowing them to easily dissolve in water. Precipitation breaks this interaction and creates new ones, allowing the DNA or RNA to come out of solution and be isolated easily.
