IMPROVED TECHNIQUE FOR SELECTIVE SILVER STAINING OF NUCLEOLAR ORGANIZER REGIONS IN HUMAN-CHROMOSOMES

A reliable technique for staining human chromosomal nucleolar organizers (NOR) with Ag solutions is described. The NOR can be selectively stained dark brown by Ag solutions leaving the chromosome arms unstained and available for counterstaining with orcein or Giemsa dyes. Unequivocal identification of chromosome pairs bearing NOR can be achieved using fluorescent banding techniques followed by Ag staining. The Ag staining procedure for NOR was simplified and standardized through control of the chemical and physical conditions during Ag impregnation and developing.