Chain and conformation stability of solid-state DNA: implications for room temperature storage

Abstract

There is currently wide interest in room temperature storage of dehydrated DNA. However, there is insufficient knowledge about its chemical and structural stability. Here, we show that solid-state DNA degradation is greatly affected by atmospheric water and oxygen at room temperature. In these conditions DNA can even be lost by aggregation. These are major concerns since laboratory plastic ware is not airtight. Chain-breaking rates measured between 70°C and 140°C seemed to follow Arrhenius’ law. Extrapolation to 25°C gave a degradation rate of about 1–40 cuts/105 nucleotides/century. However, these figures are to be taken as very tentative since they depend on the validity of the extrapolation and the positive or negative effect of contaminants, buffers or additives. Regarding the secondary structure, denaturation experiments showed that DNA secondary structure could be preserved or fully restored upon rehydration, except possibly for small fragments. Indeed, below about 500 bp, DNA fragments underwent a very slow evolution (almost suppressed in the presence of trehalose) which could end in an irreversible denaturation. Thus, this work validates using room temperature for storage of DNA if completely protected from water and oxygen.

An efficient method for long-term room temperature storage of RNA

“…To provide an optimal RNA protection at ambient temperature, we extended to RNA a procedure previously validated for the storage of DNA. 23,24 In this process, RNA is thoroughly dried in the presence of an additive and kept in airtight and waterproof stainless steel minicapsules under an anhydrous and anoxic atmosphere.…”

Assessing a novel room temperature DNA storage medium for forensic biological samples

“…There are a greater range of samples that could be tested including those resulting from alternate extraction methods such as Chelex extracted DNA [23] or the new Prepfiler extraction method [24]. Storage studies utilizing DNA from additional extraction methods are underway; however, it is likely the outcome will be similar regardless of the condition of the sample, because truly dried samples are unlikely to degrade [10]. Additional testing on a wider range of samples is recommended to establish a sound basis for using SM.…”

“…Additional factors that may compromise sample integrity include high humidity, temperature, persistence of nucleases and other chemical agents as well as other sub-optimal conditions that may occur not only during transport, but also within storage facilities [10]. Typically, cold conditions (i.e.…”

“…Such a requirement has not always been practical, especially for some types of evidentiary samples and particularly for DNA extracts. Thus, there is a need to develop effective alternative strategies for storage procedures [10][11][12].…”

From Hard Drives to Flash Drives to DNA Drives

“…Memory cards are said to be reliable for up 5 years after their initial use, but DNA-encoded information remains stable and readable for millennia. 5 For purposes of timeless storage, DNA may be dried and then protected from water and oxygen, which gives it a nearly infinite stability. DNA information storage is not new.…”