Abstract
Accurate DNA quantification is required for the short tandem repeat typing of forensic samples. Various commercial DNA quantification kits for forensic DNA analysis have recently been released. However, DNA quantification may fail if too much PCR inhibitor is extracted with the target DNA sample. Therefore, this study experimentally evaluated the degree of the alteration of DNA quantification results of various commercial DNA quantification kits (Takara RR281, Quantifiler Duo DNA Quantification Kit, Plexor HY System, Investigator Quantiplex HYres Kit, Quantifiler Trio DNA Quantification Kit, and Quant-iT dsDNA HS Assay Kit) in the presence of various concentrations of PCR inhibitors such as hematin, humic acid, indigo carmine, melanin, and tannic acid. Compared to the other kits, the DNA quantification abilities of the Investigator Quantiplex HYres Kit and Quant-iT dsDNA HS Assay Kit were not negatively affected by high concentrations of hematin. The DNA quantification abilities of the Quantifiler Trio DNA Quantification Kit and Quant-iT dsDNA HS Assay Kit were not negatively affected by high concentrations of PCR inhibitors containing humic acid, indigo carmine, or melanin. The DNA quantification abilities of the Investigator Quantiplex HYres Kit and Quantifiler Trio DNA Quantification Kit were not negatively affected by high concentrations of tannic acid. Furthermore, the DNA quantification ability of the Quantifiler Trio DNA Quantification Kit was more reproducible than those of the other kits. Moreover, this kit was able to assess the degree of DNA degradation by comparing quantified both the short amplicon (80 bp) and long amplicon (130 bp). However, the short amplicon was not negatively affected by high concentrations of PCR inhibitors in contrast to the long amplicon. These results indicate forensic DNA analysts should select the appropriate DNA quantification kits that are unaffected by PCR inhibitors and carefully interpret DNA quantification results.
