Histone post-translational modifications associated with the transcriptional start site (TSS) of sexually dimorphic genes in 2i embryonic stem cells. Transcripts were defined as sex dimorphic from RNA-seq data using a genome-wide corrected p-value < 0.1 and −0.5 < log fold change (male/female) > 0.5. The average log fold change (male/female) is shown on the x axis. Enrichment for specific post-translational histone modifications was calculated for the 3 kb surrounding the TSS from ChIP-seq data generated from 2i ES cells (y axes). Correlations for sex dimorphic X-linked genes and TSS (A) H3K4me3 enrichment (t-test p-value < 2.2 × 10−16 (mean = −0.136)) (B) H3K9me3 enrichment (t-test p-value < 2.2 × 10−16 (mean = 0.619)) (C) H3K27me3 enrichment (t-test p-value = 0.04 (mean = 0.037)). Correlations for dimorphically expressed autosomal genes and TSS (D) H3K4me3 enrichment (ρ = 0.57, p-value < 2.2 × 10−16) (E) H3K9me3 enrichment (ρ = 0.0052, p-value = 0.89) (F) H3K27me3 enrichment (ρ = −0.077, p-value = 0.036).