Fig. 4

Epigenetic signatures allow predicting paternally expressed imprinted genes (PEGs). a The combination of CHG methylation in the central cell together with maternal-specific H3K27me3 and H3K9me2 allows predicting previously described PEGs [14, 24]. Scores are calculated as described in the Additional file 2: Table S1. High and low scores correspond to high or low levels of CHG methylation, H3K27me3, and H3K9me2, respectively. Number of PEGs corresponds to PEGs previously predicted [14] (i) and [24] (ii) in Col and Ler accessions. Total genes correspond to all genes present in the corresponding categories. Box plots show mean values of maternal to total reads in the indicated categories. Boxes show medians and the interquartile range, error bars show the full range excluding outliers. Blue line indicates the expected ratio for biallelically expressed genes. b Box plots show relative expression level of genes in the seed coat of torpedo stage embryos [22]. Genes present in the highest score category (Additional file 3: Table S2) were grouped in paternally biased genes (chi-square test, P < 0.05 Bonferroni corrected) and not-paternally biased genes. Asterisks mark significance (Wilcoxon rank sum test, P < 5.0e−3)