DNA Specimen Preservation using DESS and DNA Extraction in Museum Collections: A Case Study Report

Background

Advancements in molecular biology have made DNA analysis an essential component of taxonomic and biodiversity research. Museum collections, traditionally focused on morphological preservation, now face growing demands to maintain DNA integrity in specimens [1,2,3]. However, the high cost and space requirements of freezer storage make it impractical for large-scale implementation [4,5]. 

DESS (dimethyl sulfoxide, EDTA, and saturated NaCl) has been proposed as a promising room-temperature alternative for DNA preservation [6,7,8]. This study investigates the efficacy of DESS compared to conventional methods across a broad taxonomic range, evaluating both morphological retention and DNA integrity. The hypothesis tested is that DESS can preserve high molecular weight DNA at room temperature while maintaining morphological structures suitable for taxonomic study [2,6].

Key findings

Preservation performance across taxa
DESS was shown to preserve high-quality DNA (>15 kb fragments) across diverse taxa, including nematodes, arthropods, birds, fungi, algae, and seagrasses, under ambient conditions. In nematodes, DNA was successfully extracted even after a decade of storage. When whole organisms were preserved, optimal DESS concentrations for morphology and DNA integrity varied by species, indicating taxon-specific responses. Notably, in some cases, DNA integrity remained intact even after complete evaporation of the DESS solution, highlighting its robustness.

Morphological compatibility and practical application
Unlike ethanol or RNAlater, which can cause tissue dehydration and morphological distortion, DESS enabled better retention of taxonomic characters in soft-bodied and delicate specimens. The study underscores the value of DESS for both long-term and temporary storage—particularly in field settings or institutions lacking cryogenic infrastructure. Variants such as DESS-NMNS (with Tris and sodium sulfite) further optimized preservation in fungi.

Museomics and non-destructive extraction
DESS also facilitates non-destructive DNA extraction in small or rare specimens, aligning with museomics goals of minimizing damage to irreplaceable material. Museomics is a relatively recent interdisciplinary field that refers to the application of genomic and molecular techniques to museum collections, allowing researchers to extract DNA from preserved specimens while preserving their morphological and historical value. This approach bridges traditional taxonomy with modern molecular biology, enabling evolutionary, ecological, and conservation insights from archived biological materials.

For example, DNA barcoding was possible in marine nematodes without destroying morphological integrity. This suggests DESS could serve as a bridge between molecular and morphological conservation in natural history repositories, supporting both genomic research and long-term specimen preservation.

Why this study is important

This case report stands out as one of the most comprehensive demonstrations of DESS’s utility across multiple phyla and real-world museum contexts. By systematically evaluating the method’s effectiveness for both DNA preservation and morphological integrity, it provides compelling evidence of DESS as a robust, adaptable, and cost-effective solution for long-term specimen storage. This is particularly relevant for institutions managing large, taxonomically diverse collections, where traditional ultra-cold storage solutions are often logistically unfeasible and economically inaccessible.

Implications

Beyond technical considerations, the implications of this work align with broader shifts in biological sciences toward the integration of museomics, a field that leverages genomic technologies to study natural history collections without compromising specimen integrity [1,3,4]. This paradigm enables non-destructive or minimally invasive access to genetic material from rare or irreplaceable specimens, opening new avenues in evolutionary biology, systematics, and conservation genomics [4,13].

Importantly, solutions like DESS carry significant potential for museums and field stations in low- and middle-income countries, particularly across Latin America, where biodiversity is vast but financial and logistical constraints are considerable [5,14]. In regions where infrastructure for ultra-low temperature storage is scarce, DESS offers a viable and scalable alternative that can democratize access to molecular tools [7,10]. Likewise, remote biological stations in tropical ecosystems could benefit from the portability and resilience of DESS-based protocols, allowing researchers to preserve genetic material effectively in situ, without immediate dependence on refrigeration or freezing [5,6,12].

As global initiatives increasingly prioritize open-access genomic resources and inclusive biodiversity monitoring, developing robust, low-cost, and field-ready preservation methods is critical [3,11,15]. This study thus contributes not only to methodological innovation, but also to the decentralization of molecular biodiversity research, promoting equity in scientific discovery across geographies and institutions [9,14].

Questions

Q1. Taxon-specific optimization of DESS concentrations:

While the manuscript mentions that optimal DESS concentrations varied by species, can the authors elaborate on how these differences were evaluated? Would it be possible to provide a summary table or decision-making guide for choosing DESS concentrations based on specimen characteristics (e.g., size, tissue type, taxonomic group, time)?

For example, in taxa with high water content—such as echinoderms like sea cucumbers—was a dilution or pre-dehydration step required to avoid tissue degradation or dilution of the preservative? Similarly, how did preservation success vary between soft-bodied versus heavily sclerotized specimens?

Clarifying these details could not only strengthen the reproducibility of the study but also help establish taxon-specific best practices, enhancing the method’s utility across biological collections and field applications. Do the authors envision future development of protocol checklists or concentration calculators based on specimen traits?

Q2. Non-destructive extraction reproducibility and DNA yield:

The study refers to non-destructive DNA extraction as one of DESS’s advantages, especially for nematodes and delicate taxa. Can the authors provide comparative yield data (e.g., ng/μL or fragment size profiles) between destructive and non-destructive protocols using DESS? What are the trade-offs in terms of DNA quantity or purity?

Q3. Long-term stability and field deployment:

The study highlights DNA integrity even after DESS evaporation. Can the authors quantify DNA degradation over extended periods beyond 10 years, and under varying field-like conditions (e.g., temperature fluctuations, light exposure)? How would DESS perform in truly extreme environments such as tropical field stations?

Q4. Comparative morphological assessment:

The manuscript asserts that DESS preserves morphology better than ethanol-based methods. However, no quantified morphological scoring or side-by-side imaging comparisons are presented. Would the authors consider including visual or metric evidence such as shape retention, color fidelity and tissue shrinkage. As well as other morphometric measures such as cell perimeter, aspect ratio, circularity, etc,  to objectively support these claims?

Q5. Standardization and protocol scalability for museum settings:

Given the diversity of taxa and methodologies used, what recommendations do the authors propose for protocol standardization across institutions? Could a tiered or modular workflow be suggested for scaling up DESS-based preservation for high-throughput use in large collections? Perhaps a workflow could be provided to better encompass the study.

Additionally, considering the success demonstrated in both DNA integrity and morphological preservation, is there potential for these protocols to be systematized for applications beyond traditional museum settings? For example, could the authors suggest guidelines or decision trees tailored for remote biological stations, conservation genetics programs, or community-based biodiversity monitoring efforts?

In short, can the authors envision how this preservation strategy might be integrated into global biodiversity infrastructure, helping to bridge gaps in molecular access between institutions of different scales and geographic regions?

Disclaimer

AI tools such as Consensus and Elicit were used to certify that the gathered references did not have author biases and were representative of the toxicology field.

References

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Tags: biodiversity research, dess method, dna preservation, dna quality, museum collections, specimen integrity

doi: https://doi.org/10.1242/prelights.42938

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