where each location had a peak for each antibody tested. The region at ~4.4 kb is adjacent to the small tAg, the inserted element. The area around ~2.7 kb is in a region that exhibits sequence similarity to the mouse genome and most likely represents either an artifact of the alignment or an additional SV40 sequence present in the transgene but not originally annotated. In contrast to the peaks identified in GMO sample 1, the other two GMOs and all four wild-type samples had no peaks aligning to the SV40 genome. It is not unexpected that GMO sample 2 failed to have peaks aligning to SV40 even though it contained an intron of the SV40 genome since the histone antibodies used in these experiments are not known to bind to intronic regions.