Abstract：
The use of DNA methylation to predict chronological age has shown promising potential for obtaining additional information in forensic investigations. To date, several studies have reported age prediction models based on DNA methylation in body fluids with high DNA content. However, it is often difficult to apply these existing methods in practice due to the low amount of DNA present in stains of body fluids that are part of a trace material. In this study, we present a sensitive and rapid test for age prediction with bloodstains based on pyrosequencing and random forest regression. This assay requires only 0.1 ng of genomic DNA and the entire procedure can be completed within 10 h, making it practical for forensic investigations that require a short turnaround time. We examined the methylation levels of 46 CpG sites from six genes using bloodstain samples from 128 males and 113 females aged 10-79 years. A random forest regression model was then used to construct an age prediction model for males and females separately. The final age prediction models were developed with seven CpG sites (three for males and four for females) based on the performance of the random forest regression. The mean absolute deviation was less than 3 years for each model. Our results demonstrate that DNA methylation-based age prediction using pyrosequencing and random forest regression has potential applications in forensics to accurately predict the biological age of a bloodstain donor.
摘要：
使用DNA甲基化来预测实际年龄已显示出在法医调查中获得其他信息的有希望的潜力。迄今为止,一些研究报道了基于DNA含量高的体液中DNA甲基化的年龄预测模型。然而,由于在作为痕量物质的一部分的体液染色剂中存在少量的DNA,因此在实践中应用这些现有方法通常是困难的。在这项研究中,我们提出了一种基于焦磷酸测序和随机森林回归的血迹年龄预测的灵敏而快速的检验方法。该测定只需要0.1ng的基因组DNA，整个过程可以在10小时内完成，使其适用于需要较短周转时间的法医调查。我们使用来自10至79岁的128名男性和113名女性的血迹样本，检查了来自6个基因的46个CpG位点的甲基化水平。然后使用随机森林回归模型分别构建男性和女性的年龄预测模型。基于随机森林回归的性能，开发了具有七个CpG位点（男性三个，女性四个）的最终年龄预测模型。每个模型的平均绝对偏差小于三年。我们的结果表明，使用焦磷酸测序和随机森林回归的基于DNA甲基化的年龄预测在法医学中具有潜在的应用，可以准确预测血迹供体的生物年龄。本文受版权保护。保留所有权利。
