Selective staining of animal chromosomes with synthetic dyes following iodine-dye-procedure

The paper embodies results of the use of 51 synthetic dyes, belonging to different chemical groups for staining of animal chromosomes following iodine-dye procedure. It has been found that some of these dyes can replace gentian violet, crystal violet and safranin when used after this procedure. It has further been found that the fluorescent dyes, acriflavine and acridine yellow can also be used to stain animal chromosomes and that some of the dyes belonging to one chemical group can be successfully used whereas others of the same group are of no use. Dyes of the monoazo group are absolutely useless. Amongst the dyes successfully used, the preparations remain stable when stained with most of them except methyl green, malachite green, brillant green, iodine green and cresyl violet and amongst acid dyes, acid fuchsin. Cytochemical studies presented herein indicate that the components of the animal chromosomes stainable with crystal violet are the nucleic acids and that these substances should be highly polymerised and should not be even in a semi-degraded state. Removal of any one of these nucleic acids makes the chromosomes unstainable with iodine-crystal violet.