(a) Cluster analysis of C (blue), N (red) and CN (grey) expression profiles where all samples were median-centred and treated as they were independent experiments. Minimum presence per cDNA clone was set to 7 out of 9 in each data set. (b) Histogram of pair-wise Euclidean distances over all samples for IMAGE clones. For each IMAGE in 9 dimensions, i.e. hybridization 1–9, the Euclidean distance between C and N is √(Σi = 1 (Ci-Ni)2) where Ci and Ni is the log2ratio for C and N probe respectively for hybridization i. (c) Histogram of distances between C and N probes for all IMAGE for each hybridization.