( H.C. Birnboim DNA...)DNA Stability with Oragene

H.C. Birnboim
DNA Genotek, Ottawa, Ontario, Canada

Storage of specimens by refrigeration or freezing can add significant costs to a project. Oragene eliminates these costs by allowing saliva specimens to be stored for years at room temperature without DNA degradation.

Introduction
Large population-based studies, involving hundreds to thousands of subjects, are frequently used to investigate the genetic determinants of complex diseases. Saliva is a convenient source of genomic DNA because it can be collected in a painless and non-invasive manner. For logistic reasons, samples often need to be stored prior to the extraction of DNA. Common storage methods, such as refrigeration and freezing, can add significant costs and inconvenience to a genetic study. In addition, these methods may be of limited effectiveness. For example, Ng et al. (2004) observed as much as a 30% decrease in PCR product yield from saliva samples that had been stored at -70C for 1 month.

An ideal protocol would allow saliva samples to be stored at room temperature for long periods of time with no DNA degradation. Oragene is a kit that collects and preserves DNA from saliva. This technical bulletin reports the ability of Oragene to stabilize and preserve DNA in saliva at temperatures up to 50C.

Materials and Methods
Oragene/saliva samples were collected and stored at room temperature (24C), 37C, and 50C for up to 187 days. At various time intervals, aliquots were removed and processed by the standard Oragene protocol. 200 ng of DNA from each sample was analyzed by agarose gel electrophoresis with ethidium bromide staini
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