Reconstruction of the copy number amplification of the ERBB2 oncogene. (A) Copy number and translocations for the amplified region on Chr 17 that includes ERBB2 showing the relations to Chr 8. Note Chr 8 has extensive rearrangements shown by the green intra-chromosomal arcs. (B) Sequence of events that best explains the copy number and translocations found in this region. Segment 1 (orange) first translocated into Chr 8, followed by the segment 2 (yellow) translocating to a different place on Chr 8. Then, the segment 3 (green) was duplicated from segment 2 by an inversion of the piece between variants D and E along with a 1.5-Mb piece of Chr 8 that was attached at variant E, all of which then attached at variant C. The whole green segment including the 1.5 Mb of Chr 8 then underwent an inverted duplication at variant D. The purple segment could have come from the orange, yellow, or green sequences since it only shares breakpoint A. Additionally, there is a deletion of 10,305 bp between breakpoints D and E.
