FIG. 5.

Hierarchical clustering showing the gene expression profiles of 13 different P. brasiliensis genes during the M-Y (A) and Y-M (B) transitions (Fig. 4). In both experiments, relative levels of each transcript were monitored by real-time RT-PCR with mRNA extracted at the beginning of the differentiation process (T = 0) and also at different time points after the temperature-induced switch. These values were used to calculate the relative expression ratios against time T = 0. These ratios were log transformed and submitted to a hierarchical clustering algorithm by using the default parameters of the software CLUSTER, kindly provided by M. Eisen and available at http://www.microarrays.org/software.html. In both cases, as shown by the scales in the right, a color scheme was used to designate genes that were downregulated (blue) or upregulated (red). The clustering, along with the resulting dendrogram, was displayed by using TREEVIEW, also available at the same URL mentioned above (14).