Figure 1.

Principle of tumor progression tree reconstruction. (a) CGH log ratio profiles of two bladder tumors from the same patient, with color code as follows: homozygous deletions in blue, losses in green, normal regions in yellow, and gains in red. Chromosomes are delineated by gray vertical lines and a schematic representation of chromosomes and centromeres is drawn below each profile. Chromosome breakpoints common to both samples are indicated by dashed lines, with an arrow representing the sign of each breakpoint. For greater clarity, the common breakpoints on either side of the one-BAC homozygous deletion at 9p21 are not drawn. This common aberration is instead circled in each profile. (b) Tumor progression tree reconstructed for the two samples. Common breakpoints define early aberrations occurring in the common precursor of the two samples. Chromosome aberrations specific to each tumor are placed on subsequent edges.