Figure 7.

Fluorescence in situ hybridization demonstrating the instability of the marked chromosome in subclones G60 and G71 that have nontelomeric DNA joined on to the end of the marked chromosome. Metaphase chromosomes from subclones G60 (A, B, E, F) and G71 (C, D) were hybridized with either the pNCT-Δ plasmid probe (A, C, E) or a chromosome-16-specific probe (B, D, F) and the chromosomes were counter stained with propidium iodide. Extensive heterogeneity was observed in the structure of the marked chromosome, including the presence of chromosome 16 fragments of different lengths joined on to the end (A, B), dicentric chromosomes involving the marked chromosome and other chromosomes (C, D), and amplification of the marked chromosome with chromosome-16-specific fragments interspersed with fragments of other chromosomes (E, F).