OPTIMIZING STORAGE AND HANDLING OF DNA EXTRACTS
Steven Lee, C. Crouse, and M. Kline
Nucleic acid sample storage is of paramount importance in forensic science, epidemiological,
clinical and genetic laboratories. Millions of biological samples, including cells,
viruses, and DNA/RNA, are stored every year for diagnostics, research and forensics.
PCR has permitted the analysis of minute sample quantities. Forensic samples such
as bone, teeth, touch samples and some sexual assault evidence may yield only low
quality and low quantity DNA/RNA. Efficient storage of the extracted DNA/RNA is needed
to ensure the stability of the sample over time for re-testing of the CODIS STRs,
mtDNA, YSTRs, mRNA and other future marker typing systems.
Amplification of some or all of these markers may fail because the biological material
has been highly degraded, contains inhibitors, is too low in quantity or is contaminated
with contemporary DNA. Reduction in recovery has been observed with refrigerated liquid
DNA extracts and also those exposed to multiple freeze-thaw cycles. Therefore, the
development of optimal storage and amplification methods is critical for successful
recovery of profiles from these types of forensic samples, since in many cases, re-testing
This review is divided into three sections. Section One covers the background of forensic
DNA storage, factors that influence DNA stability, and a brief review of molecular
strategies to type non-optimal DNA. Section Two covers the importance of DNA extract
storage in forensic and non-forensic DNA databanks, and the mechanisms responsible
for loss during storage. Finally, Section Three covers strategies and technologies
being utilized to store DNA.
July 20th, 2010 | Forensic Science Reviews, 2010, 22:131-144
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