Representative metaphase cell FISH images of SC and LC probes. A) Hybridization pattern in a normal cell of LC probe 2 with targets in BP1 (2869 bp) and BP3 (2837 bp) to both chromosome 15s. B) Hybridization of LC probe 5 (1637 bp) on normal chromosomes. The pattern is similar to that of an SC probe, as the paralogous target of probe 5 exhibits high sequence divergence and is not detected. The next 4 panels show chromosome hybridizations on cells of Class I (C, D) and Class II (E, F) AS deletions. C) LC probe 2 hybridization pattern in WJK36 cell. Only the BP3 target is deleted in the abnormal chromosome (arrow), as determined by subsequent hybridization with SC probe 4 (not shown). The normal chromosome shows hybridization to all paralogous targets. Loss of the BP3 target sequence with this probe was also evident in WJK 70 (Class I), WJK18 and WJK24 (Class II). D) Dual-color hybridization with LC Probe 2 (green) and SC probe 3 (1861 bp, red) in WJK67 (Class I). Probe 2 is intact on both chromosomes and was confirmed by sequential hybridization. Probe 3 is deleted on the abnormal homolog (arrow), and a similar outcome for this probe was noted for WJK70. E) Deletion of SC probe 7 (1812 bp) (arrow) in WJK35. Deletions of probe 7 were also seen in WJK67, WJK70 and WJK36. F) SC probe 10 (2055 bp) is intact in WJK24. Similar hybridization patterns were seen in WJK70, WJK36 and WJK18. All probes were labeled with digoxigenin or biotin- dUTP and detected with Cy-3 digoxin antibody or FITC-avidin, respectively. Cells are counterstained with DAPI.