# Long-Term Tissue Preservation at Ambient Temperature for Post-Mass Fatality Incident DNA-Based Victim Identification

## TL;DR

This study compares methods for preserving tissue samples at room temperature to enable DNA-based victim identification in mass fatality incidents.

## Contribution

A simple, low-cost method for ambient temperature tissue preservation is proposed and validated for DNA integrity over 24 months.

## Key findings

- All four preservation methods maintained DNA quality for STR-PCR amplicons over 200 bp after 24 months.
- Non-iodized kitchen salt preserved high-molecular-weight DNA better than other methods.
- A low-cost ambient preservation process is proposed for use in mass fatality incidents.

## Abstract

In a mass fatality incident (MFI), effective preservation of tissue samples is the cornerstone for downstream DNA-based identification of victims. This is commonly achieved through freezing of tissue samples excised from bodies/fragmented remains which may be buried or stored in refrigerated containers. This may, however, not be possible depending on the nature of the MFI; in particular, during armed conflict/war where extended periods of electrical outages would be expected. The present study compared the effectiveness of long-term tissue preservation at ambient temperatures using two commercial products (non-iodized kitchen salt and a 40% alcoholic beverage) against a chemical preservative (Allprotect™ Tissue Reagent (Qiagen, Germantown, MD, USA)) and freezing at −20 °C. Bovine muscle tissue, used as a proxy for human tissue, was treated with the four preservation methods and sampled at six different time-points over a 24-month period. All four methods were able to preserve the bovine tissue, generally yielding STR-PCR (Short Tandem Repeat-Polymerase Chain Reaction) amplicons > 200 bp in size even at the end of 24 months. Gel electrophoresis, however, indicated that salt was more effective in preserving DNA integrity with high-molecular-weight DNA clearly visible as compared to the low-molecular-weight DNA smears observed in the other methods. This study also proposes a simple process for the rapid and low-cost preservation of tissue samples for long-term storage at ambient temperatures in support of post-incident victim identification efforts.