Institute of Legal Medicine, University Hospital Düsseldorf, 40225, Düsseldorf, Germany.
Institute for Systems Neuroscience, University Hospital Düsseldorf, 40225, Düsseldorf, Germany.
Int J Legal Med. 2022 Mar;136(2):405-413. doi: 10.1007/s00414-021-02736-3. Epub 2021 Nov 5.
As a contribution to the discussion about the possible effects of ethnicity/ancestry on age estimation based on DNA methylation (DNAm) patterns, we directly compared age-associated DNAm in German and Japanese donors in one laboratory under identical conditions. DNAm was analyzed by pyrosequencing for 22 CpG sites (CpGs) in the genes PDE4C, RPA2, ELOVL2, DDO, and EDARADD in buccal mucosa samples from German and Japanese donors (N = 368 and N = 89, respectively).Twenty of these CpGs revealed a very high correlation with age and were subsequently tested for differences between German and Japanese donors aged between 10 and 65 years (N = 287 and N = 83, respectively). ANCOVA was performed by testing the Japanese samples against age- and sex-matched German subsamples (N = 83 each; extracted 500 times from the German total sample). The median p values suggest a strong evidence for significant differences (p < 0.05) at least for two CpGs (EDARADD, CpG 2, and PDE4C, CpG 2) and no differences for 11 CpGs (p > 0.3).Age prediction models based on DNAm data from all 20 CpGs from German training data did not reveal relevant differences between the Japanese test samples and German subsamples. Obviously, the high number of included "robust CpGs" prevented relevant effects of differences in DNAm at two CpGs.Nevertheless, the presented data demonstrates the need for further research regarding the impact of confounding factors on DNAm in the context of ethnicity/ancestry to ensure a high quality of age estimation. One approach may be the search for "robust" CpG markers-which requires the targeted investigation of different populations, at best by collaborative research with coordinated research strategies.
作为对基于 DNA 甲基化 (DNAm) 模式的种族/祖籍对年龄估计可能影响的讨论的贡献，我们在一个实验室中直接比较了德国和日本供体在相同条件下的与年龄相关的 DNAm。通过焦磷酸测序分析了德国和日本供体颊黏膜样本中 22 个 CpG 位点（CpGs）（PDE4C、RPA2、ELOVL2、DDO 和 EDARADD 基因）（分别为 N=368 和 N=89）。这 20 个 CpG 与年龄具有非常高的相关性，随后对年龄在 10 至 65 岁之间的德国和日本供体之间的差异进行了测试（分别为 N=287 和 N=83）。通过对日本样本进行年龄和性别与德国亚样本（N=83 个；从德国总样本中提取 500 次）进行测试，进行了协方差分析。中位数 p 值表明至少有两个 CpG（EDARADD，CpG2 和 PDE4C，CpG2）存在显著差异的强证据（p<0.05），而 11 个 CpG 无差异（p>0.3）。基于来自德国训练数据的所有 20 个 CpG 的 DNAm 数据的年龄预测模型并未显示日本测试样本与德国亚样本之间的相关差异。显然，包含的“稳健 CpG”数量较多，阻止了两个 CpG 中 DNAm 差异的相关影响。然而，所提供的数据表明需要进一步研究种族/祖籍对 DNAm 的影响，以确保年龄估计的高质量。一种方法可能是寻找“稳健”CpG 标志物-这需要针对不同人群进行有针对性的研究，最好通过具有协调研究策略的合作研究来实现。
