Fig. 6.

Overview of sample preparation and the combination of storage variables analyzed. Sample size for each of the storage variable combinations is denoted by “n=”. Small aliquots are represented by solid lines, while 1-liter storage size (DNA only) is represented by dotted lines. For all storage sizes, DNA extraction was performed on 400 µl of slurry and RNA extraction was performed on 300 µl of slurry. RNA was reverse transcribed to cDNA for PCR amplification and subsequent sequencing, with DNA directly PCR amplified and sequenced. Both DNA-based and cDNA-based analysis was performed on fresh samples (Day 0) and frozen samples at both storage temperatures (-20 °C and − 80°Cat Day 30, 60, and 90 of frozen storage. For the aliquots stored in 1-liter volumes these were analyzed with DNA-based analysis only after 90 days of storage at -80 °C