Solexa sequencing profile of derivative chromosome 9 from patient 1. 1-Mb intervals around the breakpoints on chromosome 7 (A) and 9 (B) are shown. 199,421 and 1,047,649 reads derived from the der (9) were mapped to unique positions on normal chromosomes 7 and 9, respectively. The number of reads was then binned into nonoverlapping 1-kb segments and plotted against the chromosome coordinates. (Arrows) Breakpoints.