Age prediction is of great importance for criminal investigation and judicial expertise. DNA methylation status is considered a promising method to infer tissue age by virtue of age-dependent changes on methylation sites. In recent years, forensic scientists have established various models to predict the chronological age of blood, saliva, and semen based on DNA methylation status. However, hair-inferred age has not been studied in the field of forensic science. In this study, we measured the methylation statuses of potential age-related CpG sites by using the multiplex methylation SNaPshot method. A total of 10 CpG sites from the LAG3, SCGN, ELOVL2, KLF14, C1orf132, SLC12A5, GRIA2, and PDE4C genes were found to be tightly associated with age in hair follicles. A correlation coefficient above 0.7 was found for four CpG sites (cg24724428 and Chr6:11044628 in ELOVL2, cg25148589 in GRIA2, and cg07547549 in SLC12A5). Among four age-prediction models, the multiple linear regression model consisting of 10 CpG sites provided the best-fitting results, with a median absolute deviation of 3.68 years. It is feasible to obtain both human identification and age information from a single scalp hair follicle. No significant differences in methylation degree were found between different sexes, hair types, or hair colors. In conclusion, we established a method to evaluate chronological age by assessing DNA methylation status in hair follicles.

中文翻译：

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通过检测头发中的 DNA 甲基化状态预测人类年龄

年龄预测对于刑事调查和司法专业知识非常重要。DNA甲基化状态被认为是一种很有前途的方法，通过甲基化位点的年龄依赖性变化来推断组织年龄。近年来，法医科学家建立了各种模型，根据 DNA 甲基化状态预测血液、唾液和精液的实足年龄。然而，头发推断的年龄尚未在法医学领域进行研究。在这项研究中，我们使用多重甲基化 SNaPshot 方法测量了潜在的与年龄相关的 CpG 位点的甲基化状态。来自LAG3、SCGN、ELOVL2、KLF14、C1orf132、SLC12A5、GRIA2和PDE4C基因被发现与毛囊的年龄密切相关。发现四个 CpG 位点的相关系数高于 0.7（ELOVL2 中的 cg24724428 和 Chr6:11044628 、 GRIA2 中的cg25148589和SLC12A5中的 cg07547549）。在四个年龄预测模型中，由 10 个 CpG 位点组成的多元线性回归模型提供了最佳拟合结果，中位绝对偏差为 3.68 岁。从单个头皮毛囊中获取人类身份和年龄信息是可行的。在不同性别、头发类型或头发颜色之间没有发现甲基化程度的显着差异。总之，我们建立了一种通过评估毛囊中 DNA 甲基化状态来评估实足年龄的方法。