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

To resolve cases involving unidentified cadavers, the study of polymorphic DNA markers of old bones is an invaluable but often challenging tool used in 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 that develop during the postmortem phase), and the coextraction 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 was to improve the collection of extracted DNA compared with 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 presented.The modified method for the extraction of genomic DNA, followed by amplification reaction, allowed for identification of 4 cadavers and typification of 1 cadaver. The study carried out involved unidentified cadavers, or their remains, discovered after a long period from time of death.