| Summary: | 碩士 === 國防醫學院 === 生物化學研究所 === 94 === This main purpose of this study is to investigate the DNA analytical techniques for the specimens of human hair shafts and nails. We compared two kinds of DNA extraction methods, phenol-chloroform and QIAamp DNA micro kit. Either from hair shaft or from nail samples, the former method showed higher yield as quantitated by Real-time PCR. The inhibition of PCR reaction by melanin was not observed in the DNA quantitation by Real-time PCR in which the DNA sample solution from hair shafts was diluted 5-fold. However, for STR typing, the PCR reaction of AmpFIST® Profiler Plus was inhibited by melanin when the dilution of DNA sample solution from hair shafts was less than 3-fold. Previous study has found the degradation of DNA by nuclease in hair shafts and nails. This is further confirmed as the amounts of DNA extracted from hair shafts and nails required for STR typing using AmpFlSTR® Profiler Plus™ with 28 PCR cycles are 10.53 ng and 1.32 ng, respectively, corresponding to 4.68 mg hair shafts and 0.02 mg nails. When the PCR cycle number for the same PCR typing reaction was increased from 28 to 34, in contrast to 10.3 ng, only 1.32 ng DNA extracted from hair shafts was required to provide complete STR typing results. In addition, our study has suggested that the proximal part of hair shafts has a higher DNA content than the distal end has. For sequencing of mitochondrial HV1 and HV2 DNA, 1.11 x 10-3 mg and 4.44 x 10-2 mg of hair shafts and 1.75 x 10-5 and 1.75 x 10-4 mg of nails are needed, respectively. The results derived from this study will facilitate the forensic DNA analysis using samples of hair shafts and nails
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