§16§This study was aimed to compare between four DNA extraction methods, including phenol-chloroform-isoamyle, guanidine hydrochloride, saturated sodium chloride, and chelex-100 using 50 blood samples collected from healthy volunteers. The comparison included DNA concentration, extracted DNA purity, cost of reagents per one sample, and time consuming. After a comprehensive analysis of all factors: salt extraction gave the maximum yield of DNA, it is saver and simpler than the other methods. Moreover, this method is reliable and inexpensive. But its purity is slightly low. Phenol-chloroform-isoamyl extraction method give reliable quantity and purity of the DNA extracted. But it takes a time and labor in obtaining pure extract. Moreover, its associated toxicities warrant a judicious use. Chelex-100 resin extractions gave a DNA quantity as well as phenol-chloroform- isoamyle extraction. It is save, simple, does not require any organic solvent, and takes very short time and a little possi §16§bility of cross contamination. But it is expensive. Guanidine hydrochloride extraction is an expensive method taking a long time with a low quantity and quality of the DNA obtained.
