Fan Jiajia, Yu Huan, Yang Hailing, Zhang Yuxin, Zhang Mingming, Wang Jiaqi, Liu Zidong, Liu Jinding, Li Zeqin, Zhang Gengqian
School of Forensic Medicine, Shanxi Medical University, Jinzhong, Shanxi 030619, China.
Forensic Sci Int Genet. 2025 Jan;74:103158. doi: 10.1016/j.fsigen.2024.103158. Epub 2024 Oct 9.
Hair is one of the most common forms of forensic biological material at various crime scenes. So far, human identification cannot be effectively accomplished with a single telogen hair encountered in forensic casework due to the detection limit. Emerging studies have revealed RNA as a promising biomarker in hair shafts, while the single telogen hair could not be successfully genotyped even after being examined with the recently developed mRNA typing system. MALDI-TOF MS, the matrix-assisted laser desorption/ionization time-of-flight mass spectrometry, enables sensitive and accurate measurement of DNA products. To address this problem and further develop the analysis technology of hairs, we established a mass spectrometry system for human identification based on a single hair shaft using 25 polymorphic SNPs located on 18 mRNA molecules (KRT31, RFK, KRT86, KRT35, PABPC1, KMT2D, LEMD2, TBC1D4, CTC1, PPP1R15A, RBM33, LRRC15, KRT33A, KRTAP12-2, KRT81, AHNAK, KRTAP4-8, FLG2). The forensic application of the detection system was evaluated, and all hair samples used were collected from individuals in Shanxi province. Firstly, we demonstrated that the RNA typing results of a single hair shaft were in perfect concordance with DNA typing results and confirmed the consistency between hairs from different body parts. To assess the potential influence of positions along the hair shaft, 6 cm long hair shafts from the distal end were examined by the MALDI-TOF MS system, whose genotype could be successfully detected. The system was capable of detecting aged samples stored for 390 days and could also be employed on various types of hair samples, such as white hair and permed or dyed hair. Finally, 50 unrelated individuals from Shanxi province were genotyped for the population study, and the CDP of the system in the Shanxi population is 0.998928. In this study, we established a mass spectrometry system for human identification based on a single hair shaft. We used a single hair shaft, rather than multiple hair shafts reported in our previous report, to get a full typing profile. The system sensitivity was substantially enhanced, which provided a valuable strategy for forensic practice to perform human identification using hairs.
毛发是各类犯罪现场最常见的法医物证形式之一。由于检测限的原因，在法医案件工作中遇到的单根休止期毛发目前尚无法有效实现个体识别。新兴研究表明RNA是毛干中有前景的生物标志物，然而即使使用最近开发的mRNA分型系统对单根休止期毛发进行检测，也无法成功进行基因分型。基质辅助激光解吸/电离飞行时间质谱（MALDI-TOF MS）能够灵敏且准确地测量DNA产物。为解决这一问题并进一步发展毛发分析技术，我们基于单根毛干建立了一种用于个体识别的质谱系统，该系统使用位于18个mRNA分子（KRT31、RFK、KRT86、KRT35、PABPC1、KMT2D、LEMD2、TBC1D4、CTC1、PPP1R15A、RBM33、LRRC15、KRT33A、KRTAP12-2、KRT81、AHNAK、KRTAP4-8、FLG2）上的25个多态性单核苷酸多态性（SNP）。对该检测系统的法医应用进行了评估，所有使用的毛发样本均采集自山西省的个体。首先，我们证明了单根毛干的RNA分型结果与DNA分型结果完全一致，并证实了来自不同身体部位毛发之间的一致性。为评估沿毛干不同位置的潜在影响，对距末端6厘米长的毛干通过MALDI-TOF MS系统进行检测，其基因型能够成功检测。该系统能够检测储存390天的陈旧样本，也可用于各类毛发样本，如白发以及烫染过的毛发。最后，对来自山西省的50名无关个体进行基因分型以开展群体研究，该系统在山西人群中的个体识别能力（CDP）为0.998928。在本研究中，我们基于单根毛干建立了一种用于个体识别的质谱系统。我们使用单根毛干而非我们之前报告中所采用的多根毛干来获得完整的分型图谱。该系统的灵敏度得到了显著提高，为法医实践中利用毛发进行个体识别提供了一种有价值的策略。
