H3K9me3 - tri-methylation of lysine 9 of H3. Repressive mark. Typically referred to as a heterochromatic mark. (IHEC reference epigenome). This a repressive mark that frequently marks repeats (LTRs, LINEs,..) and their flanking regions. It is distributed widely across the human genome. The presence of the mark in the genic promoters is weakly anticorrelated with gene expression.
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