Figure 4.

Germline imprints in the cynomolgus macaque. DNA methylation in macaque gametes fall into three distinct groups of paternally (A) and maternally (B) acquired germline imprints, and a third group (C) with delayed maternal imprint acquisition. Except for PLAGL1 (lower oocyte image: GV only; upper oocyte image: MII only), all other oocyte samples comprised of pooled stages (GV, MI, and MII). In D, macaque oocyte methylation is shown alongside meta-analysis of data from Smith et al. (2014), showing that the lack of oocyte methylation at PLAGL1, PEG3, and INPP5F_v2 (patterned bars) is consistent with human, where methylation is gradually acquired across the primate embryonic cleavages, and only completed by the blastocyst stage. In contrast, mouse homologs show that imprinted methylation is present in oocytes and already complete in the early zygote. The intronic KCNQ1/Kcnq1 DMR (gray bar) is shown for comparison. No data were available for mouse Peg3. (Left axis, bar chart) Absolute DNA methylation, (right axis, line graph) percent DNA methylation relative to level in ICM/blastocyst.