High-efficiency automated DNA extraction method for degraded old skeletal samples

Abstract

In case of extreme degradation, bone may be the only suitable material available for successful STR genotyping. However, relatively specialized techniques are required for the extraction of DNA from bone tissues, particularly when the bones have been exposed to adverse environmental conditions and DNA is degraded and present in low concentrations. In this study, to optimize DNA extraction procedure for old and highly degraded skeletal remains, newly developed automated DNA extraction system was compared to the traditional organic DNA extraction methods We adopted Chemagic Magnetic Separation Module I system for automated DNA extraction, with optimized protocols for large volumes (range, 5–15mL) of bone samples. Success rates of genotyping were analyzed by STR genotyping, and mtDNA sequencing analysis. Real-time assays for quantification revealed that human DNA yield from skeletal samples did not show remarkable differences between two methods However, Chemagic MSM I system showed lower concentration of co-extracted PCR inhibitors than the traditional organic extraction methods Furthermore, STR genotyping results showed that Chemagic MSM I system is more effective DNA extraction method for old skeletal remains than organic extraction method. Therefore, here we suggest that the Chemagic MSM I system is efficient automated DNA extraction system for old and highly degraded bone samples and powerful and valuable tool for identification of old skeletal remains.