Extraction Method of Dental DNA by Using whole Tooth Sections : Application to Forensic Odontology

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I have previously reported the forensic value of teeth as a source of DNA for genetic analysis. Commonly, dental DNA has been obtained from dental pulp. The DNA thus obtained usually contains high-molecular-weight DNA and is suitable for multilocus DNA probe analysis. In most cases seen in forensic practice, sample teeth have been left in humid conditions and the dental pulp has been degraded by endonucleases, so that its condition is too poor for analysis. I have sometimes found that dental DNA obtained from a whole tooth section is badly degraded, and suitable only for polymerase chain reaction (PCR). Moreover, on several occasions, it is not amplified by the PCR technique even though it has been confirmed by agarose gel electrophoresis that there is enough DNA for the PCR.Therefore, I suspected that some cations contaminated in tooth sections might contaminate dental DNA during its extraction as a source material for PCR,and act as a inhibitor of Taq DNA polymerase during the PCR procedure.In this study, I demonstrated conclusively that the Chelex-based procedure tenders DNAs obtained from a whole tooth section suitable for PCR amplification, and the possibility of forensic DNA analysis using those of purified dental DNA.Dental identification is traditionally based on a comparison of antemortem with postmortem dental charts and X-rays. In cases where this is impossible the usefulness of the amplification of chromosal hypervariable loci and mitochondrial DNA sequencing are undisputed and it should use as an adjunct in forensic odontological practice.