Department of Environmental Toxicology, University of California, Davis, United States.
Department of Public Health Sciences, University of California, Davis, United States.
Forensic Sci Int. 2020 May;310:110200. doi: 10.1016/j.forsciint.2020.110200. Epub 2020 Feb 25.
Proteomic genotyping uses genetically variant peptides that contain single amino acid polymorphisms to infer the genotype of corresponding non-synonymous SNP alleles. We have focused on hair proteins as a source of protein-based genetic information in a forensic context. An optimized sample processing protocol for hair shafts has been developed for use on a single hair that allows us to conduct validation protocols on real world samples. This includes whether the inferred SNP genotypes are robust and not systematically affected by biological or chemical variation in hair proteomes that might be obtained from a crime scene. To this end we analyzed the hair of 4 mature individuals with a mixture of pigmented and non-pigmented hair. We demonstrate significant changes in the proteomes of grey versus pigmented hair. Vesicle specific proteins and lipid catabolism proteins were enriched in pigmented hair, and housekeeping proteins and lipid anabolic enzymes were enriched in grey, non-pigmented hair. The resulting profiles of genetically variant peptides, however, were more correlated with profiles from the same individuals regardless of pigmentation status. Together with other published evidence, this finding indicates that profiles of genetically variant peptides are robust and more correlated with other genetically variant peptide profiles from the same individual irrespective of changes occurring in the hair protein profile. Based on this small sample, investigators using profiles of genetically variant peptides to infer random match probabilities should not expect to observe differences based on the pigmentation of the hair shaft.
蛋白质组学基因分型利用含有单个氨基酸多态性的遗传变异肽来推断相应非同义 SNP 等位基因的基因型。我们专注于毛发蛋白作为法医背景下基于蛋白质的遗传信息的来源。已经开发了一种优化的毛发轴样本处理方案，可用于单根毛发，使我们能够对真实世界的样本进行验证方案。这包括推断的 SNP 基因型是否稳健，并且不受可能来自犯罪现场的毛发蛋白质组中生物或化学变异的系统影响。为此，我们分析了 4 名成熟个体的毛发，其中混合了有色素和无色素的毛发。我们证明了灰色与有色素毛发的蛋白质组之间存在显著变化。囊泡特异性蛋白和脂质分解代谢蛋白在有色素毛发中富集，而管家蛋白和脂质合成酶在灰色、无色素毛发中富集。然而，遗传变异肽的特征图谱与同一个体的图谱更为相关，而与色素沉着状态无关。结合其他已发表的证据，这一发现表明遗传变异肽的特征图谱是稳健的，并且与同一个体的其他遗传变异肽特征图谱更相关，而与毛发蛋白质特征图谱中的变化无关。基于这个小样本，使用遗传变异肽特征图谱来推断随机匹配概率的研究人员不应该期望根据毛发轴的色素沉着观察到差异。
