Placental methylation levels in regions upstream and covering the <i>H19</i> transcription start site (TSS).

<p>Each genomic region where DNA methylation was measured is highlighted in yellow and numbered 1–3. DNA methylation levels for individual CpG loci are shown for first trimester (red circles, n = 13) and term (blue circles, n = 18) placentae. Distance (bp) of cytosine nucleotide from <i>H19</i> TSS is represented on x-axis. Each data point represents the mean methylation level for the gestational age class. * Indicates a significant difference in methylation levels between first trimester and term placentae at individual CpG sites. Error bars represent SEM and when not present SEM was too low to depict on the graph. The schematic representation below the graph highlights the regions between <i>H19</i> and <i>IGF2</i> where bisulfite DNA pyrosequencing was performed. Region 1 covers 5 CpG sites (Chr11∶2021011–2021070), region 2 covers 12 CpG sites (Chr11∶2021011–2021070) and region 3 covers 5 CpG sites (Chr11∶2019079–2019145). Genomic coordinates refer to reference assembly GRCh37/hg19.