The purpose of DNA extraction is to obtain DNA in a relatively purified form. This can then be used to analyze using PCR or sequencing the DNA obtained. In a DNA extraction procedure there are essential components which are to maximize DNA recovery, remove inhibitors, remove or inhibit nucleases, maximize the quality of DNA, and double strand vs. single strand (RFLP or PCR). There are a variety of most commonly used DNA extraction procedures. The method utilized may be sample dependent, technique dependent, cost depedndent, or analyst preference.