Preservation of corals in salt-saturated DMSO buffer is superior to ethanol for PCR experiments

Specimen collection is time consuming and expensive, yet few laboratories test preservation methods before setting out on field expeditions. The most common preservation buffer used for coral specimens is > 70% EtOH. However, alternatives exist that are less flammable, easier to ship, and are widely used in other taxa. Here, we compare the effects of salt-saturated DMSO (SSD) and EtOH preservation buffers on post-extraction DNA quantity and quality. We found that soft tissue integrity was better maintained and higher quantities of DNA were extracted from EtOH-preserved specimens; however, by all other measures, SSD was a superior preservative to EtOH. Extractions of SSD-preserved specimens resulted in higher molecular weight DNA, higher PCR success, and more efficient amplification than specimens preserved in EtOH. Our results show that SSD is generally a superior preservative to EtOH for specimens destined for PCR studies, but species-specific differences indicate that preservation comparisons should be undertaken before collection and storage of samples.