Clustering of the expression profiles of 2,359 genes that were defined as significantly changed across the six developmental stages of Norton berry skin. Clustering was performed using k-means statistics and 20 clusters were chosen for further analysis of transcriptional patterns. The number of genes in each cluster is listed in parenthesis. The X-axis indicates grape berry developmental stages in days after bloom (DAB); The Y-axis indicates the Log2-transformed fold-change of stage-specific intensity relative to the baseline intensity of each gene. The véraison phase is denoted by purple bar. A list of genes, their ChipID, Genoscope ID, putative function, Enzyme ID and pathway in Vitisnet for each cluster is included in Additional File 6.