Dehydration as a means of preserving DNA in forensic samples
The aim of this investigation is to validate the use of dehydration as a possible storage method for the long term preservation of DNA in biological forensic case samples. Currently trace forensic DNA case samples are preserved using freezer storage at -20 ° C or -80 ° C. Freezer storage preserves the sample by slowing down or eliminating the effects of environmental attack that are the cause of DNA degradation. Freezer storage incurs long term costs from maintenance and renewal, for which no viable alternative has previously been proposed. The Bode Technology Group ä in the USA has since recognised this by way of integration of a silica desiccant into the casing of their Crime Scene Collector ä sterile cotton swabs. The use of Bode Crime Scene Collector ä swabs has a high initial cost impact with no subsequent expense, offering a suitable cost effective alternative. In this investigation DNA degradation was analysed by comparing peak area ratios of each storage method over time using the ABI PRISM â 3130 Genetic Analyser. The results of this investigation showed that whilst there is little difference in storage methods in the short term, desiccation does not offer long term protection of sample DNA. A preliminary study into the use of freeze-drying was also considered which offered no short or long term proposal of effective DNA storage.
Lucy Neale, School of Life Sciences, University of Westminster and Ignacio Quinones Garcia, Kings College, London.
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