Figure 7.

SKY karyotype of a metaphase spread from a pancreatoblastoma cell line. Left, inverted DAPI chromosomes; right, classification pseudo-colors. Some of the aberrations consist of multiple chromosomal segments, as indicated by numbers to right of chromosomes. Assignments of these chromosome segments were subsequently confirmed with whole chromosome–painting probes to rule out the sandwich effect. This effect is visible on the chromosome 11 aberration (asterisk). Only the chromosome 15 at the boundary of chromosome segments 11 and 4 was verified; hence, the segment identified as coming from chromosome 12 is an artifact resulting from the sandwich effect, or merging of two overlapping fluorochromes. There is no normal chromosome 7 in this karyotype. To classify any segments that involve chromosome 7, a red lasso was drawn around a chromosome 7 segment (identified by its banding pattern and spectral color) contained in the derivative chromosome 4, the chromosome 7 segment was manually placed in the chromosome 7 compartment, and finally the karyotype was reclassified.