A region of heterochromatin that is formed dynamically under specific growth conditions by a process that requires RNAi, and is enriched in histone H3 methylated on lysine 9 (H3K9me).
Source:PMID:24210919,
PMID:23151475
Comment
An example of this type of heterochromatin is found in Schizosaccharomyces pombe, where heterochromatin domains preferentially assemble at sexual differentiation genes and retrotransposons.