Extraction of DNA from bones in cases where expectations for success are low

In order to resolve cases involving unidentified cadavers, the study of polymorphic DNA markers of old bones is an invaluable, but often challenging tool used in the field of forensic genetics. Some of the difficulties encountered involve the limited quantity of endogenous DNA, its subsequent degradation (a result of elapsed time, environmental conditions and the microorganisms which develop during the postmortem phase), and the co-extraction of substances that inhibit amplification reactions. For these reasons, it is necessary to direct research toward the development of new extraction techniques with the goal of obtaining adequate quantities of high-quality DNA. The aim of this study is to improve the collection of extracted DNA compared to the amount of DNA obtained with the NucleoSpin® DNA Trace kit (Macherey Nagel) protocol for the extraction of genomic DNA from human bones. A modified version of the standard protocol is here presented. The modified methodology for the extraction of genomic DNA, followed by amplification reaction, allowed the identification of four cadavers and the typification of a fifth. The study carried out involved unidentified cadavers, or their remains, discovered after a long period from time of death.