Breeding and Genetics: Molecular Biology and Genomics

Preservation of bio-specimens for molecular biological applications traditionally involves freezing which increases laboratory and research project costs. Protection and stabilization of DNA at room temperature (RT) may eliminate the costs associated with freezer storage. However, there is a paucity of information describing the yield, purity, and integrity of DNA stored at RT. Objectives were to evaluate the yield, purity, and integrity of DNA extracted from whole blood samples stored at RT, low (−20°C), and ultra-low (−80°C) temperatures. Sheep (n = 4 [7 mL]) and human (n = 6 [4 mL]) whole blood samples were collected and aliquots stored at RT, −20°C, and −80°C. Blood samples at RT were stored utilizing bio-stabilization technology (DNAstable Blood and DNAgard Blood; Biomatrica, San Diego, CA) designed to protect genomic DNA in whole blood from degradation resulting from unprotected RT storage. Negative control samples were stored unprotected at RT. Genomic DNA was extracted by using the QIAamp DNA Blood Mini Kit (Qiagen, Valencia, CA). Quantification and purity of the extracted DNA was determined by spectrophotometry and the integrity was assessed following electrophoresis. The DNA yield was not influenced by a species × storage temperature interaction (P = 0.84). Similarly, storage temperature did not influence DNA yield (P = 0.52) and averaged 13.6 ± 1.2 ng/μL across all storage temperatures. Among samples stored protected at RT, species, type of technology utilized, and the interaction did not (P > 0.13) influence DNA yield with yield averaging 12.5 ± 1.2 and 12.7 ± 1.2 ng/μL for DNAgard and DNAstable, respectively. The 260/280 ratio was influenced by a species × storage temperature interaction (P = 0.01). In general, the 260/280 ratios were higher (P < 0.05) for human samples stored at low and ultra-low temperatures compared with sheep samples stored at similar low temperatures. In conclusion, ambient temperature-based bio-stabilization technologies may offer an alternative to traditional low temperature-based bio-specimen preservation and storage.