<unk>  is an epigenetic modification to the DNA packaging protein Histone H3. It is a mark that indicates the tri-methylation at the 9th lysine residue of the histone H3 protein and is often associated with heterochromatin.
H3K9me3
H3K9me2
H3K36me
H4K8ac
H3K14ac
H4K5ac
H4K12ac
H3K9ac