Forensic DNA Division, National Forensic Service, Wonju, 26460, Korea.
DNA Analysis Division, National Forensic Service Seoul Institute, Seoul, 08036, Korea.
Genes Genomics. 2021 Jul;43(7):749-758. doi: 10.1007/s13258-021-01066-3. Epub 2021 Apr 19.
Short tandem repeats (STR) typing is an essential analysis method for human identification in forensic field. When DNAs obtained from the field as evidences are severely degraded or in too small amounts, STR analysis often shows allele drop-out.
To improve STR analysis for degraded DNA or trace DNA, reduced-size STR (rSTR) polymerase chain reaction (PCR) system was devised by selecting relatively large-size STR loci.
The rSTR PCR system consisted of 8 loci (amelogenin, SE33, CSF1PO, D7S820, D13S317, D2S1338, TPOX, and FGA). The size of PCR product was reduced by designing new primers in the flanking region. The efficiency of this system was verified against existing kits through concordance study, sensitivity study, efficiency study, and casework sample study.
The size of PCR product in the rSTR PCR system was reduced to be less than 322 bp. The amplicon of each locus was reduced by about 100 bp on average. Results of this rSTR PCR system were confirmed using 146 Korean samples and other commercial kits. The rSTR PCR system was capable of analyzing DNA samples with a minimum amount of DNA of 16 pg and a degradation index of 4.215.
The rSTR PCR system was more effective than other PCR kits for obtaining genetic profiles from a small amount of DNA or degraded DNA. The combination of this new system and other commercial kits is more effective than existing systems. This combination is expected to be helpful for the identification of unidentified bodies and skeletal samples.
短串联重复序列（STR）分型是法医领域进行人类身份识别的一种重要分析方法。当作为证据的 DNA 严重降解或数量过少时，STR 分析通常会出现等位基因缺失。
为改善降解 DNA 或痕量 DNA 的 STR 分析，本研究设计了一种通过选择相对较大 STR 基因座的小 STR（rSTR）聚合酶链反应（PCR）系统。
rSTR PCR 系统由 8 个基因座（amelogenin、SE33、CSF1PO、D7S820、D13S317、D2S1338、TPOX 和 FGA）组成。通过在侧翼区域设计新引物，将 PCR 产物的大小减小。通过一致性研究、灵敏度研究、效率研究和案例样本研究，验证了该系统与现有试剂盒的效率。
rSTR PCR 系统的 PCR 产物大小减小到 322bp 以下。每个基因座的扩增子平均减少约 100bp。使用 146 个韩国样本和其他商业试剂盒验证了该 rSTR PCR 系统的结果。rSTR PCR 系统能够分析最小 DNA 量为 16pg 和降解指数为 4.215 的 DNA 样本。
与其他 PCR 试剂盒相比，rSTR PCR 系统在从少量 DNA 或降解 DNA 中获取遗传谱方面更有效。这种新系统与其他商业试剂盒的结合比现有的系统更有效。这种组合有望有助于识别无名尸体和骨骼样本。
