Figure legend : (A) The 724 and 518 genes significantly induced during the sporulation process in the fission (green) and budding (blue) yeasts were mapped in a 3-dimensional space, according to the expression measurements during the time course experiments described in Mata et al. 2002 and Chu et al. 1998. Points represent genes, and white segments link pairs of genes for which the inter-gene distance between their expression measurements is less than a threshold D0 = 0.3 (a conventional correlation higher than 0.95). 3D visualizations and snapshots were obtained using the rgl package.
(B) Using the k-means algorithm, genes were classified according to their expression profiles into four classes named "Nitrogen" (blue), "Early" (green), "Middle" (red) and "Late" (yellow). Genes contained in each group are shown as different colours so that they can be identified in the gene expression network. Unlike in (A), only the first and the second coordinates are represented here.