Insights into DNA Stability (Part 1)
Researchers are often and understandably cautious about the idea of transporting extracted DNA at room temperature. DNA is traditionally viewed as a sensitive molecule that requires frozen or dry ice conditions to maintain stability. To address these legitimate concerns, we conducted a proof-of-concept experiment to validate if room temperature shipping preserves DNA integrity while simplifying logistics. Below, we share findings.
Test results on DNA stability at room temperature
To evaluate the feasibility of room temperature shipping for extracted DNA samples, DNA was extracted from a single environmental wastewater sample following Resistomap SOP. The extracted DNA was aliquoted and stored at room temperature, and DNA concentration and quality measurements were conducted at multiple time points over a 26-day period to assess stability. Aliquots were stored at -20°C after each time series point prior to SmartChip qPCR analysis. Below is a summary of key metrics relevant to the potential of room temperature shipping for maintaining DNA integrity:
.png)
.png)
What can we gather from these results?
- Concentration Stability:
The DNA concentration remained stable, fluctuating slightly but staying within the range of 9.4 to 11.2 ng/µL. This is a minor variance that doesn’t impact the sample’s usability in typical qPCR or sequencing applications. Even at 26 days, the Quantus reading showed only minor fluctuation, from an initial 6.7 ng/µL down to 5.1 ng/µL
- Purity ratios:
Both the 260/280 and 230/260 ratios, which indicate the presence of proteins, chemical residues, and other contaminants, remained close to their ideal ranges (around 1.8 for 260/280 and 2.0–2.2 for 230/260). While the 260/280 ratio stayed stable, minor decreases over time were observed in the 230/260 ratio. These changes are still well within acceptable limits and don’t indicate significant contamination or quality loss for the first 2 weeks.
What this means for DNA shipping
Our findings suggest that extracted and purified DNA samples are more resilient than often assumed, remaining stable under room temperature conditions such as short-term shipments of up to two weeks. For context, our typical shipping times are around 48 hours within the EU and up to 96 hours for our longest shipment from New Zealand. By removing the need for dry ice, we can eliminate extra costs and resource use across all aspects of the shipment, while also significantly lowering CO₂ emissions. Not using dry ice reduces CO₂ emissions by an average of 86% per shipment alone, not including the emissions associated with sourcing and handling dry ice in the first place—a small but still meaningful win for the environment.
To summarise, shipping extracted DNA at room temperature is a practical and low-risk option for researchers, particularly for short-term express transportation.
Next up: Analysing the DNA
In our next blog post on this topic, we’ll dive into the second phase of this experiment: HT-qPCR analysis and statistical evaluation of the results. Using the same room temperature stored samples, we specifically examined whether any DNA fragmentation occurred—and we’re excited to share that the results were just as positive as in this first phase.
Stay updated with our newsletter
Sign up to receive the latest blog posts and updates directly in your inbox.