Figure 2.

(a) Digital images of normal human chromosomes hybridized with a biotinylated p7–6 cosmid probe comprising exons 2 and 3 counterstained with propidium iodide. Chromosomes 2, 9, 15, 18, and 21 exhibit double symmetrical fluorescent signals. Chromosomes 9 and 18 have signals on both short and long arms and chromosomes 21 have two pairs of signals on the long arm. (b) The same metaphase as in a showing G-like banding pattern generated by contrast enhancement and LUT (look-up table) inversion of the image of 4′,6-diamidino-2-phenylindole-restained chromosomes. The resolution of the chromosome bands permits an accurate individual chromosome identification as well as the regional localization of the fluorescent signal. (c) Orangutan chromosomes hybridized with a biotinylated p7–6 cosmid probe. Two chromosome pairs exhibit hybridization signal on the long arm. (d) The same metaphase as in c rehybridized with human chromosomes 15 (biotin-labeled, yellow) and 21 (digoxigenin-labeled, red) probes for chromosome identification. These probes painted the orangutan chromosomes homologous to human 15 and 21. The long arm of chromosomes 15 and the distal segment of the long arm of chromosome 22 where KGF sequences are located are painted. (e) Gibbon chromosomes hybridized with a biotinylated p7–6 probe (yellow signal) and a digoxigenin-labeled chromosome 21 probe. Chromosome 15 in gibbon has homology with human chromosomes 15 and 21. Two chromosomes 15 exhibit fluorescent signal on the distal part of the long arm corresponding to human chromosome 21 as shown by painting (red).