Optimizing Storage and Handling of DNA Extracts

Area of Science:

• Forensic Science
• Molecular Biology
• Genetics

Background:

• Millions of biological samples (cells, viruses, DNA/RNA) are stored annually for diagnostics, research, and forensic applications.
• Polymerase Chain Reaction (PCR) enables analysis of minute sample quantities, but low-quality/quantity DNA/RNA from sources like bone, teeth, or touch samples presents challenges.
• Degradation, inhibitors, low quantity, and contamination can lead to amplification failure, necessitating efficient storage for retesting.

Purpose of the Study:

• To review the critical importance of nucleic acid sample storage in forensic and non-forensic databanks.
• To examine factors influencing DNA/RNA stability during storage.
• To explore current and emerging strategies and technologies for optimal DNA/RNA storage.

Main Methods:

• Literature review focusing on forensic DNA storage, factors affecting DNA stability, and molecular typing strategies for suboptimal DNA.
• Analysis of mechanisms responsible for DNA/RNA loss during storage.
• Examination of various storage strategies and technologies.

Main Results:

• Refrigerated liquid DNA extracts and samples undergoing freeze-thaw cycles show reduced recovery rates.
• Degraded, low-quantity, or contaminated samples pose significant challenges for DNA/RNA amplification and profile recovery.
• Effective storage is essential for maintaining sample integrity for future analyses, including CODIS STRs, mtDNA, YSTRs, and mRNA.

Conclusions:

• Optimal storage and amplification methods are critical for successful recovery of genetic profiles from challenging samples.
• Maintaining sample stability over time is paramount for ensuring the reliability of forensic and genetic analyses.
• Continued development of storage technologies is needed to address the challenges of preserving low-quality and low-quantity nucleic acid samples.