H3K27me3 is a chromatin modification depositied by Suz12, a component of the Polycomb Group 2 complex, and is associated with transcriptional repression. In contrast, H3K79me2 is a chromatin modification associated with active gene transcription. It is deposited by the histone methyltransferase Dot1L and generally is localized just downstream of the transcriptional start site and extends down the body of the gene. To gain insight into the transcriptional state of genes in hES cells, chromatin immunoprecipitation coupled with massive parallel sequencing (ChIP-seq) was performed to determine the genome-wide occupancy of the H3K27me3 and H3K79me2 chromatin modifications and genome-wide occupancy of the Suz12. DNA was enriched by chromatin immunoprecipitation (ChIP) and analyzed by Solexa sequencing A sample of whole cell extract was sequenced and used as the background to determine enrichment. ChIP was performed using an antibody against H3K27me3, H3K79me2, and Suz12 (Abcam).