Wu Pei-Wen, Mason Katelyn E, Durbin-Johnson Blythe P, Salemi Michelle, Phinney Brett S, Rocke David M, Parker Glendon J, Rice Robert H
Forensic Science Graduate Program and Department of Environmental Toxicology, University of California, Davis, CA, USA.
Forensic Science Center, Lawrence Livermore National Laboratory, Livermore, CA, USA.
Proteomics. 2017 Jul;17(13-14). doi: 10.1002/pmic.201600462. Epub 2017 Jun 23.
Forensic association of hair shaft evidence with individuals is currently assessed by comparing mitochondrial DNA haplotypes of reference and casework samples, primarily for exclusionary purposes. Present work tests and validates more recent proteomic approaches to extract quantitative transcriptional and genetic information from hair samples of monozygotic twin pairs, which would be predicted to partition away from unrelated individuals if the datasets contain identifying information. Protein expression profiles and polymorphic, genetically variant hair peptides were generated from ten pairs of monozygotic twins. Profiling using the protein tryptic digests revealed that samples from identical twins had typically an order of magnitude fewer protein expression differences than unrelated individuals. The data did not indicate that the degree of difference within twin pairs increased with age. In parallel, data from the digests were used to detect genetically variant peptides that result from common nonsynonymous single nucleotide polymorphisms in genes expressed in the hair follicle. Compilation of the variants permitted sorting of the samples by hierarchical clustering, permitting accurate matching of twin pairs. The results demonstrate that genetic differences are detectable by proteomic methods and provide a framework for developing quantitative statistical estimates of personal identification that increase the value of hair shaft evidence.
目前，毛发证据与个体的法医关联主要是通过比较参考样本和实际案件样本的线粒体DNA单倍型来评估，主要用于排除目的。当前的工作测试并验证了更新的蛋白质组学方法，以从同卵双胞胎对的毛发样本中提取定量转录和遗传信息，如果数据集中包含识别信息，预计这些信息会与无关个体区分开来。从十对同卵双胞胎中生成了蛋白质表达谱以及多态性、基因变异的毛发肽。使用胰蛋白酶消化蛋白质进行分析表明，同卵双胞胎的样本中蛋白质表达差异通常比无关个体少一个数量级。数据并未表明双胞胎对中差异程度随年龄增加。同时，消化数据用于检测由毛囊中表达基因的常见非同义单核苷酸多态性产生的基因变异肽。变异的汇编允许通过层次聚类对样本进行分类，从而实现双胞胎对的准确匹配。结果表明，蛋白质组学方法可检测到遗传差异，并为开发个人识别的定量统计估计提供了框架，从而增加了毛发证据的价值。
