Figure 2.

Mutagenic selection of genetic instability. Bardelli et al. (3) started out with the genetically stable cell line H3 (HCT 116 artificially complemented with chromosome 3). This cell line was first exposed to selection pressure involving cytotoxic levels of PhIP. The selected cells expressed CIN, illustrated as a trisomy and a translocation. The same cell line (H3) then was exposed to selection pressure involving cytotoxic levels of MNNG (N-methyl-N′-nitro-N-nitrosoguanine). This time the selected cells expressed MIN, illustrated as slippage in a repetitive sequence. The experiment thus supports the hypothesis that the CIN and MIN phenotypes reflect Darwinian adaptations to different mutagenic environments, methylating and BAF agents, respectively.