| In the event of a mass disaster, a large number of victims must be located and identified, and it is difficult to process the site in a timely and orderly manner. Many victims may only be identified through DNA analysis; therefore, obtaining viable tissue samples is of great importance. Likewise, tissue preservation of remains discovered in very remote areas can also be hindered. The goal of this study was to examine protocols for on-site preservation of tissues that would later undergo DNA analysis. Tissue samples were taken over the course of one week from recently killed pig carcasses that had been placed in a field during the summer. Six preservation methods were evaluated: storage of tissue in ethanol, isopropanol, RNAlater, and silica, as well as oven drying (70°C) and freezer storage (-20°C). Muscle and skin samples were collected and preserved in 0.500g sections. DNA extractions were performed after two weeks and two months of storage, and DNA quality and quantity were assessed using a series of swine specific PCR assays. Samples from each of the methods evaluated were able to amplify nuclear DNA fragments of up to 642bp. Tissue type and level of decomposition significantly affected DNA quality. Ethanol and RNAlater were shown to preserve DNA of the highest quality, though differences among preservation methods were not significant. Field practicality was considered in conjunction with the DNA evaluations, and the results of this study indicated that each technique could be implemented in the field and used to preserve DNA of a quality amenable to forensic analyses. |
