Fig. 1

Analysis of whole-genome DNA methylation profiles. a Experimental design of the current study. I, Natural control: natural MII oocytes were harvested without any hormone treatment. II, hCG control: mice were treated with 5 IU hCG, and then the MII oocytes were harvested. III, FSH group: mice were intraperitoneally injected with 5/50/200 IU FSH. Forty-eight hours later, 5 IU hCG was injected, and after 14 h, the MII oocytes were harvested. IV, hMG group: mice were intraperitoneally injected with 5/50/200 IU hMG. Forty-eight hours later, 5 IU hCG was injected, and after 14 h, the MII oocytes were harvested. The methylome of each single oocyte was quantified with single-cell pBAT sequencing. b Sample sizes of the groups used in the current study. c Boxplot of whole-genome CG methylation levels. ns: not significantly different compared with natural control. d Heatmap of average promoter methylation levels. Each row represents a gene promoter and each column represents an oocyte. The gonadotropin treatment for each oocyte is shown at the top of the heatmap. e Average DNA methylation levels of gene bodies. The genomic compartments of the oocytes included 15 kb upstream of the transcription start sites (TSS) and 15 kb downstream of the transcription end sites (TES). f Pearson correlation clustering of the oocytes. The gonadotropin treatment of each oocyte is shown on the top of the heatmap, while the cluster tree shows methylome similarity. g Boxplot showing the correlations within (intra) and between (inter) the oocyte groups with different gonadotropin treatments