Mammalian chromosome identification in interspecific hybride cells using "Hoechst 33258"

Treatment of fixed chromosome preparations of mouse-human hybrid cells with the benzimidazol derivative "Hoechst 33258" makes it possible to distinguish between mouse and human chromosomes. Treatment of live cells results in differential condensation of mouse and human centromeric regions. The effects of the dye on a mouse-human translocation and the species specific differences of staining and of condensation are in accordance with the assumption that the action of "H 33258" is specifically dependent on the base composition of the DNA.