Graphical representations of the variables selected by sPLS, Ross data set. Example of graphical representation of the genes selected on the first two sPLS dimensions. The coordinates of each gene are obtained by computing the correlation between the latent variable vectors (ξ1, ξ2) and the original Ross data set. The selected cDNAs are then projected onto correlation circles where highly correlated cDNAs cluster together. These graphics help identifying correlated genes between the two platforms (by superimposing graphics from Figures 5 and 6). They also allow for the association between the gene clusters and a type of tumor cell lines by combining the information contained in Figure 4. The labels of the cDNAs can be plotted interactively in R to facilitate their identification. Subsets of the selected genes may also be displayed alone to focus on specific, user-defined, gene groups.