DNA/RNA Preservation in Glacial Snow and Ice Samples

Area of Science:

• Environmental microbiology
• Molecular biology techniques

Background:

• Preserving nucleic acids from challenging environments like glaciers is difficult for field scientists.
• Low biomass samples and logistical constraints pose significant challenges for sample integrity.

Purpose of the Study:

• To compare the effectiveness of three preservation methods (flash freezing, RNAlater, Zymo DNA/RNA Shield) for DNA and RNA from glacial snow and ice microbial communities.
• To determine best practices for nucleic acid preservation in remote and logistically challenging field settings.

Main Methods:

• Collected glacial snow and ice samples in Iceland, melting and filtering them upon collection.
• Preserved filters using liquid nitrogen flash freezing, RNAlater, or Zymo DNA/RNA Shield.
• Analyzed nucleic acid recovery, library preparation, genome assembly, and taxonomic diversity for comparative statistics.

Main Results:

• DNA-based microbial community composition was comparable across preservation methods at the class level.
• RNA-based community composition was influenced by filtered sample volume (biomass).
• Low biomass samples showed altered signatures, while high biomass samples yielded comparable results across methods; Zymo DNA/RNA Shield provided higher RNA yield.

Conclusions:

• Flash freezing is recommended for preserving low biomass DNA and RNA from glacial samples, despite logistical challenges.
• For high biomass samples, Zymo DNA/RNA Shield is favored for its superior RNA yield.
• Sample biomass quantity is a critical factor for successful collection and preservation in glacial environments.