Intercellular NOR-AG variability in man

Abstract
A new modification of the Ag I technique has been developed using human cultured blood lymphocytes, which involves ultra-violet irradiation of chromosome preparations during incubation in AgNO3. This technique enables detection in a short incubation time all NORs capable of being stained with silver. A peculiar morphological change in Ag-stainable NORs during the incubation is described, which can be used as a criterion of the completion of Ag staining. With the refined Ag-staining procedure, acrocentric marker chromosomes were studied which showed one or two satellite stalks within the same individual. Ag staining was highly coincident with this variability.