DNA profiling from human bone cells in the absence of decalcification and DNA extraction

Bone cells are a suitable substrate for DNA analysis if required to identify the person from whom a sample was taken. Osteocytes, the most abundant cell type in bone, are embedded within mineralized bone matrix. To release DNA from osteocytes for subsequent analyses, either demineralization of the mineral matrix or an overnight incubation is routinely carried out. In this study, we report on a simplified and rapid approach to analyze preserved bone samples that omits this lengthy decalcification process. Nine tibial bone samples were processed to release matrix-free bone cells after fragmentation without the use of liquid nitrogen. Cell morphology was assessed by microscopy at 220× magnification following staining with Diamond^™ Nucleic Acid Dye. Based on the presence of stained nuclei, samples were processed either using a DNA extraction process or by a semi-direct PCR process. The analysis of the quantity and quality of DNA isolated by both methods was carried out by real-time PCR and STR profiling to assess inhibition of PCR and DNA degradation. All samples resulted in informative STR profiles with minimal indication of inhibitors. These results demonstrate a potential approach of STR profiling from matrix-free bone cells within 8 hours without decalcification and DNA extraction.