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Optimal Storage Conditions for Highly Dilute DNA Samples: A Role for Trehalose as a Preserving Agent

NCJ Number
211282
Journal
Journal of Forensic Sciences Volume: 50 Issue: 5 Dated: September 2005 Pages: 1101-1108
Author(s)
Steve Smith B.Sc.; Phillip A. Morin Ph.D.
Date Published
September 2005
Length
8 pages
Annotation
This paper examines the use of the compound trehalose in the handling, storage, and preservation of low concentration DNA samples.
Abstract
Within the scope of DNA studies, the quality and usefulness of extracts from nontraditional samples vary widely and are thought to be greatly influenced by factors such as method employed for DNA isolation and storage and handling of DNA extracts prior to genotyping. However, there are few studies to guide researchers seeking information on optimal storage conditions for DNA extracts. The study investigated factors influencing degradation in the quality and quantity of DNA extracts over time and formalizes a preferred approach to the handling and storage of low concentration DNA extracts. The results indicate that in some common storage situations, low concentration samples degrade and become otherwise unavailable for PCR amplification over time. However, the data indicate a role for trehalose as a buffer additive prior to dry storage in situations where freezer space is limited. It is further indicated that it is the stabilization action of trehalose that best explains the enhanced yield for samples dried in its presence. Trehalose forms a glass upon drying and it is this process that has been shown to stabilize proteins in a dry state due to the action of the glass-like proteins on the intra-molecular folding. In conclusion, the highest quality of DNA remained in samples stored at -80C, regardless of storage additives, and those dried at room temperature in the presence of trehalose. DNA quality was best preserved in the presence of trehalose, either dried or at -80C; significant quality loss occurred with -20C and +4C storage. Figures and references