[Variability of Chinese hamster clones in resistance to 8-azaguanine].

The stability of the 8-azaguanine resistance marker during the number of cell generations has been analyzed for 63 clones of Chinese hamster cells. The resistant clones analyzed were spontaneous or induced after the treatment of parent cells by 5-BUdR, EMS, or histone H1. The clones have revealed different levels of AG-resistance as well as different ability to maintain the above level, under the cultivation in the drug-free medium. Subclones, isolated from the unstable clone, were found to be different in both the resistance level and the stability of resistant state.