DNA methylation landscapes of human fetal development

Here we assessed the genome-scale DNA methylation of 472,703 autosomal CpG sites in 4 tissues (muscle, amnion, pancreas and adrenal glands) on 3 time-points (9, 18 and 22 weeks) using the Illumina 450k array. We identified 52,134 CpG sites with dynamic DNA methylation during fetal development (gain or loss >20% from 9 to 22 weeks), where the period between 9 and 18 weeks was most dynamic. Loss in DNA methylation (25,579 CpGs), displayed clear tissue-specific patterns near genes enriched for a role in tissue-specific processes. Gain in DNA methylation (26,555 CpGs) occurred often near genes involved in (tissue-specific) developmental processes. Comparison of DNA methylation of four fetal human tissues on three time points of gestation: 9, 18 and 22 weeks of gestation.

本研究采用Illumina 450K甲基化芯片（Illumina 450k array），对3个时间节点（孕9周、18周、22周）的4种组织（肌肉、羊膜、胰腺、肾上腺）中472,703个常染色体CpG位点（autosomal CpG sites）的全基因组DNA甲基化（genome-scale DNA methylation）水平进行了检测。本研究共鉴定出52,134个在胎儿发育过程中发生动态DNA甲基化的CpG位点，其甲基化水平变化幅度>20%（即从孕9周至22周时甲基化水平升高或降低），其中孕9周至18周为甲基化变化最为显著的阶段。其中，甲基化水平降低的25,579个CpG位点，其邻近基因显著富集于组织特异性生理过程，且该类位点呈现出清晰的组织特异性分布特征；甲基化水平升高的26,555个CpG位点，则多位于参与（组织特异性）发育过程的基因邻近区域。本研究同时对4种人类胎儿组织在3个妊娠时间节点（孕9周、18周、22周）的DNA甲基化水平进行了对比分析。