Figure 2From: Context-based FISH localization of genomic rearrangements within chromosome 15q11.2q13 duplicons SC and LC Probes Developed for FISH. A) High resolution map of LC (red) and SC (green) probes. Proximal targets of probes 1 and 2 (arrowheads) in BP1 share 99% sequence identity to their distal BP3 targets (arrowheads). Probes 3, 4, 7, 8 and 10 are adjacent to duplicon regions. LC probes 5 and 6 mimic SC probes as each have one paralog target in BP2 and their other paralogs are divergent and distal of 15q11.2q13 or interchromosomal (see text). Probe 9 serves as a deletion control that targets a sequence ~20 Kb centromeric of MAGEL2. Probe lengths are reported in base pairs (bp). B) Metaphase FISH algorithm for delineating Class I and Class II deletions in 15q11.2q13. Probes 1 through 10 are color-coded. A schema of hybridization experiments is shown for Class I and II deletions. Different outcomes indicated by the presence (+) or absence (-) of an SC (green) or LC probe (red) prescribes the procedure for delineating boundaries of a breakage interval (unfilled box). If two paralogous LC targets are retained; this is indicated by a '++' symbol. Further refinement of a deletion interval requires either sequential application of additional SC probes or dual-color/dual-probe hybridization.Back to article page