Human–mouse comparative FISH analysis of the WS region. Representative BAC clones from the ELN/Eln- and p47–phox-containing regions were selected from the physical maps of the human and mouse WS region. FISH analyses were performed on both metaphase chromosomes (insets) and interphase nuclei (main panels). Clones containing ELN/Eln (RG030E19 and 42J20) show a hybridization pattern on human chromosome 7q11.23 and mouse chromosome 5G2 typical of a single-copy segment. In mouse, the p47–phox-containing BAC (391O16) also produces a single-copy signal on metaphase and interphase chromosomes. In contrast, the human p47–phox-containing BAC (RG350L10) produces a very large and intense signal on metaphase chromosomes at 7q11.23 and multiple fluorescent dots on interphase chromosomes (also see Table 1). Sequences that cross-hybridize to the p47–phox BAC are encountered in 7p22 and 7q22 in human, in addition to the cluster in 7q11.23. We note that there is overlap between these locations and the sites detected with probes for PMS2-related sequences (Nicolaides et al. 1995).
