Definition of heterochromatin in US English:



  • Chromosome material of different density from normal (usually greater), in which the activity of the genes is modified or suppressed.

    Compare with euchromatin
    • ‘The organization of DNA into euchromatin and heterochromatin is implicated in gene silencing.’
    • ‘Studies of genes translocated to heterochromatin have provided insight into the factors that control chromatin states.’
    • ‘Numerous genes act to remodel and repress chromatin in heterochromatin and around euchromatic genes during development.’
    • ‘Thus, the density of genes in heterochromatin is about 1% of that in euchromatin.’
    • ‘Genes located in heterochromatin are transcriptionally silenced, irrespective of their own promoter sequences.’