Analysis of very similar and unrelated gene expression datasets using CIA. The first two axes of control CIA studies of very similar (A) and unrelated (B) profiles of Ross spotted cDNA gene expression data of the NCI 60 panel of cell lines are shown. The figure shows results from CIA of A) two random gene subsets of the 1375 gene dataset B) two unrelated datasets composed of 1375 genes, where the 60 cell dataset was duplicated and the arrays in one dataset were randomly permutated. Circles and arrows represent the projected co-ordinates of each dataset, and these are joined by a line, where the length of the line is proportional to the divergence between the datasets. The colours represent the eight NCI60 cell line classes as defined by Blower et al., .