Queried GO terms:

  idGO:0005720   Detailed information
  namenuclear heterochromatin
  namespacecellular_component
  def"A condensed form of chromatin, occurring in the nucleus during interphase, that stains strongly with basophilic dyes. The DNA of heterochromatin is typically replicated at a later stage in the cell-division cycle than euchromatin." [ISBN:0198506732 "Oxford Dictionary of Biochemistry and Molecular Biology"]
  is_aGO:0000790 ! nuclear chromatin
  is_aGO:0000792 ! heterochromatin
  intersection_ofGO:0000792 ! heterochromatin
  intersection_ofpart_of GO:0000228 ! nuclear chromosome

No monarch genes has this GO term.