Differential presence of a broad region of H3K9me3 affects transcription. A. H3K9me3 ChIP-chip results. B73 cells show broad region of H3K9me3 that is missing in other cell types (large arrow). Small arrow (Transcripts track) indicates CACNG7 transcript. B. Detailed view of this CACNG7 region reveals H3K9me3 presence in B73 cells but not B12 cells. H3K27me3 is not present in either B73 or B12 cells in this region. C. Quantitative PCR of mRNA abundance (cDNA) demonstrates that B12 cells contain much higher levels of CACNG7 than B73 cells. Values (mean + standard deviation) are expressed as fraction of the GAPDH level; t-test revealed p < 0.005 for this difference. Similar values were seen using ACTB as a control (see RESULTS).