Tendons and table salt: A recipe to preserve human DNA

For disaster victim identification, hundreds of samples of human remains have to be extracted from human bodies rapidly for later DNA analysis, often in situation with high humidity, high temperature and no access to cooling facilities. Genetic typing of these samples may be challenging due to degradation of DNA. Until today, bone and teeth are the preferred biological matrix for genetic identification of decomposed human remains. However, processing these samples is time and cost consuming. To address the challenges associated with workload, finances, and sample preservation in the genetic identification of unknown dead bodies, we tested 44 hand and foot tendons from deceased with advanced post mortem changes as alternative DNA material. In addition, we examined commercially available table salt as potential preservation method with 10 tendons over a period of 12 months. The parameters external appearance, DNA quantity and quality have been analysed. Overall, 39 of 44 tendons examined yielded valuable DNA profiles with at least ten autosomal STR loci. Storage in table salt not only increased DNA yield but also resulted in high quality STR profiles of the preserved tendons throughout the study period of 12 months compared to storage without salt. According to the results of this study, we recommend hand and foot tendons as alternative DNA material from bodies with advanced post mortem changes. We particularly recommend commercially available table salt as a storage medium for the preservation of DNA samples. Under field conditions without cooling facilities and the need to store samples prior to DNA analysis table salt is a good storage medium: it preserves DNA and is easily available.