Effects of preservation and storage of microcrustaceans in RNA later on RNA and DNA degradation

Methods of preserving nucleic acids are increasingly in demand because of the recent advances in molecular and biochemical approaches to ecology. The RNA storage reagent RNA later ® was tested as an alternative method to deep‐freezing for preserving RNA and DNA in zooplankton. Artemia spp. nauplii were used as test organisms. Individual RNA and DNA contents were monitored over a time period of 8 months to evaluate the effects of preservation and storage. Treatments included (1) freezing at −80±C, (2) preservation with RNA later , followed by storage at 5±C, and (3) preservation with RNA later and storage at room temperature. Freezing at −80±C was the only treatment that did not result in significant change from the initial values in any of the nucleic acids, nor at any time of the experiment. At 5±C, significant RNA degradation was not observed until 8 months after preservation while no significant changes in DNA were detected. In samples stored in RNA later without refrigeration, RNA did not exhibit significant decrease for at least 1 month, and DNA for at least 2 months. As RNA and DNA degraded at roughly the same rate, this resulted in little or no changes in RNA:DNA ratios, but withintreatment variability increased strongly. Thus, RNA later successfully preserved both RNA and DNA for up to 1 month at room temperature, and up to 4 months at 5±C, providing an alternative to the deep freezing. This method will enable a greater integration of molecular methods in ecological studies.