Heterochromatin recognition with fluorochromes

Some types of acridine derivative and especially Quinacrine dihydrochloride and its mustard may be successfully used as chromosome marker and to investigate the chemical differentiation of euchromatin and heterochromatin. — There are at least four main types of heterochromatin, showing all possible combinations of positive and negative cold effect starvation (St. + or St. -) and enhanced or reduced fluorescence (Fl. + or Fl. -). —The relationship between the four different classes of heterochromatin is not yet clear.