Following restriction enzyme digestion, we performed Southern blot analyses of BAC clones as described [20] using the pH34-U258 (5'-CTCGAGTGTACAGTCAAGTGGTTGCTGGGA-3'), pH34-U65 (5'-GTGACCCTCGTGACCCGTAA-3'), pH34-intron1L (5'-CTGCGTGAGAGAAACACCAAACAGGC-3'), pH34-L545 (5'-TGTGAATGGGAAGGTTACCACTCT-3') and pH34-SCL1 (5'-GCCCTCTTCTGGTTTGTCTCGAAAT-3') probes.