DNA repair enables sex identification in genetic material from human teeth

The purpose of this study was to test the effectiveness of a DNA repair protocol in improving genetic testing in compromised samples, frequently encountered in Forensic Medicine.

In order to stretch the experiment conditions to the limits, as far as quality of samples and DNA is concerned, we tried the repair protocol on ten ancient human teeth obtained from an equal number of skeletons from a burial site in Lerna, Middle Helladic Greece (2100-1700 BC). For these samples, sex was previously determined morphologically, serving as a reference to compare our molecular data with. The samples were analysed using the DNA amelogenin sex test assay prior and after DNA polymerase repair. For every individual, two molecular sex determinations were obtained by visualising PCR products on an agarose gel.

DNA repair enabled genetic testing in these samples. Successful amplification of the amelogenin gene was obtained only from the repaired DNA in eight out of ten samples. Prior to the repair treatment, none of these samples yielded any PCR products, thus attesting to the authenticity of the amplified sequence. The concordance between morphological and molecular analysis was in reasonable agreement (71%).

These results reveal the impact of the repair process in studying single copy genes from low quality DNA. This protocol could facilitate molecular analysis in compromised samples, encountered in forensic medicine, as well as enable genetic studies in ancient remnants.