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Preservation & High Throughput Methods for Human Tissue Samples in Tropical Climates; An Improved DVI Approach

NCJ Number
Date Published
September 2015
19 pages
This report presents the findings and methodology of a study that evaluated three customized (modified TENT, DESS, LST) and two commercial DNA preservatives (RNAlater and DNAgard) on fresh and decomposed human skin and muscle samples stored in hot (35 degrees C) and humid (60-70 percent relative humidity) conditions for up to 3 months.

Skin and muscle samples were harvested from the thigh of three human cadavers placed outdoors every second day for 2 weeks. Also, the possibility of purifying DNA directly from the preservative solutions ("free DNA") was examined in order to eliminate lengthy tissue digestion processes and increase throughput. Overall, DNAgard and the modified TENT buffer were the most effective tissue preservatives tested, based on consistently more complete STR profiles from both tissue samples and "free DNA" when decomposing tissues were stored for up to 3 months in hot, humid conditions. In addition, adequate amounts of high-quality DNA for genotyping were recovered from the preservative solutions after 1 hour of storage. The fastest (20 minutes) and most efficient method of purifying the "free DNA" in solution was the QlAquick PCR Purification kit (Qlagen). The efficiency of each preservative was assessed based on the quantity of DNA recovered from both the "free DNA" in solution and the tissue sample. The quality of DNA was measured in terms of the number of alleles recovered during downstream STR typing. 4 figures, 1 table, and 14 references

Date Published: September 1, 2015