DNA EXTRACTION FROM PLAIN SALIVA: ADVANTAGES AND LIMITATIONS
Sufficient and good quality DNA can be extracted from a variety of biological samples. In most cases, peripheral blood is the preferred source of cells. As blood harvesting is an invasive method that should be performed by trained personnel and in designated facilities, alternative DNA sources are increasingly considered. Saliva represents an important choice, and this is reflected by the growing number of commercially available saliva collecting kits. Besides being extremely easy to use, ship and store, such kits include various stabilizers and hence offer the advantage of remarkable stability of the product. However, the cost of such devices can be prohibitive. Under the circumstances, we have used plain saliva for DNA extractions. Manual extraction using silica columns and magnetic-based automated extraction were both used and compared in terms of DNA yield and purity. The DNA integrity and potential contamination with non-human DNA was also checked in human based primers PCR reactions. Furthermore, the saliva stability was checked by incubating the samples for various periods of time. We were thus able to demonstrate that plain saliva can generate adequate amounts of pure DNA, which can be used successfully in molecular biology techniques. However, in the absence of stabilizers, the samples’ stability is limited, hence they should not be stored for more than 24 hours at 4°C and they should be used for extraction within this interval.
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