Heterochromatin and Euchromatin
Heterochromatin and euchromatin are two types of chromatin structure. Heterochromatin is defined as densely packed chromatin and euchromatin is defined as loosely packed chromatin.
The condensed chromatin structure indicates inactive transcription. This is heterochromatin structure.
Methylation stop the gene expression as it blocks the promoter site from binding to transcription factors. Therefore, it indicates inactive transcription and thus heterochromatin which is condensed form of chromatin.
The loose chromatin structure indicates active transcription. This is euchromatin structure.
Acetylation of histone tails is defined as reduced attraction between nucleosomes and thus loosely packed chromatin. It allows DNA transcription and shows euchromatin structure. In deacetylation of the histone tails, chromatin recondenses and thus DNA is inaccessible for transcription.