Hierarchical clustering of genes induced by the UPR. Genes that are induced by the UPR  and changed significantly (P ≤ 0.1) during a transition from aerobic to anaerobic conditions in a XR/XDH-strain utilizing xylose  were analysed by hierarchical clustering. The heat map was generated using the log2 fold change between the different conditions. The analysis shows that a majority (61%) of the included UPR target genes are down-regulated on xylose when the conditions change from aerobic to anaerobic (Group A). These genes do not change during the same transition on glucose indicating that the UPR responds differently to xylose compared to glucose.