Fig. 6. Dynamics of H3K27 methylation in developing Drosophila embryo.

(A) Quantifications of H3K27 methylation levels in the 2-to-4-hour embryo. The black dots indicate mean values from one random inspection taken from 1000 simulations with S₃ = 3.5, k_b = 0.625 × 10⁻⁴, and k_D = 0 parameter settings. The white dots are mean values from experimental measurements in (52). The bars indicate SDs. (B) The dynamics of H3K27 methylation levels from a representative simulation of the first 4 hours of Drosophila embryonic development with parameter settings as in (A). Quantification (C) and dynamics (D) of H3K27 methylation levels measured as in (A) and (B), but with 10 times higher base methylation probability (k_b = 6.25 × 10⁻⁴). (E) Comparison of forecasted H3K27me3 within maternal (initially methylated) and paternal (initially unmethylated) alleles of the bithorax complex. Here and in (F), the box plots show distributions of differences (maternal-paternal) in mean H3K27me3 occurrence within individual nucleosomes of the bithorax complex. The mean H3K27me3 occurrence within a nucleosome was calculated from 1000 simulations. (F) Forecasted H3K27me3 within maternal and paternal alleles of the bithorax complex becomes identical at cycle 13 regardless of base methylation probability.