Performance of the Human Quantifiler, the Investigator Quantiplex and the Investigator ESSplex Plus kit for quantification and nuclear DNA typing of old skeletal remains

T. Zupanc, J. Balazic, B. Stefanic, I. Pajnic

Abstract: Aim. We tested the performance of two real-time polymerase chain reaction (PCR) human quantification kits (Human Quantifiler (Applied Biosystems) and Investigator Quantiplex kit (Qiagen)) and forensic identification short tandem repeat (STR) Investigator ESSplex Plus (Qiagen) kit on approximately 70 years old skeletal remains. Methods. We analysed 54 bones and teeth excavated from Second World War mass graves in Slovenia. Genomic DNA was obtained from 0.5 g of bone or tooth powder after total demineralization. The DNA was purified in a Biorobot EZ1 (Qiagen) device. The same extract was used for quantification and STR typing with all three kits using the amplification conditions recommended by the manufacturers. Results. In almost two thirds of the samples the results of quantification were up to 6 times higher using the Human Quantifiler than using the Investigator Quantiplex kit, because of the degradation of DNA in old skeletal remains and amplification of shorter DNA fragment with the Human Quantifiler kit. The autosomal STR typing with the Investigator ESSplex Plus kit was successful in 52 out of the 54 samples, which represent a 96% success rate. Conclusion. The commercially available Investigator ESSplex Plus kit can be used for STR typing of old skeletal remains with the DNA extraction method optimised in our laboratory and without any changes to the manufacturers PCR amplification protocols. The Human Quantifiler kit and Investigator Quantiplex kit together can be used for estimation of the degree of DNA degradation in compromised old bone samples.
Keywords: DNA quantification, autosomal STR typing, bones, teeth, Second World War.