 However, under specific developmental or environmental signaling cues, it can lose its condensed structure and become transcriptionally active.Heterochromatin has been associated with the di- and tri-methylation of H3K9 in certain portions of the genome.H3K9me3-related methyltransferases appear to have a pivotal role in modifying heterochromatin during lineage commitment at the onset of organogenesis and in maintaining lineage fidelity.