The effect of chemical compromise on the recovery of DNA from skeletonized human remains: A study of three World War II era incidents recovered from tropical locations

Abstract

The use of DNA extracted from skeletonized human remains is a common challenge for those working in human identification. Thermal age and chemical compromise should be considered prior to performing DNA testing on skeletonized remains. Both heat and chemical contamination may cause damage to the DNA present in the osseous materials and a subsequent increase in both the difficulty and expense of DNA testing. For this study, three World War II era mass fatality events involving the US military, the USS Oklahoma, the Battle of Tarawa, and the Cabanatuan Prison Camps, were examined for the overall success of DNA testing using five DNA modalities: Sanger sequencing of mitochondrial DNA, AmpFlSTR® MiniFiler™; PowerPlex® Fusion; a modified AmpFlSTR® Yfiler™; and a Next Generation Sequencing (NGS) protocol. Decedents from the three chosen incidents were buried in tropical environments and have the same approximate post mortem interval of 75 years, however, the chemical conditions that decedents were exposed to at each of the incidents vary. Remains from the USS Oklahoma were soaked in fuel oil and salt water immediately post-mortem; Cabanatuan Prison Camp remains were treated with a ‘hardening’ compound; and those from the Battle of Tarawa were not treated. Skeletal elements from each incident were compared across the 5 tested DNA modalities for success. Chemical insult to skeletal materials appears to have the greatest impact on every modality of DNA testing examined.