Relationships between the five preserved modules in the two blood data sets. The expression profiles of each preserved module were summarized by the respective module eigengene (defined as the first principal component). The correlations between the module eigengenes can be used to measure relationships between the modules (Langfelder and Horvath 2007). The hierarchical cluster tree shows the correlation relationships between the module eigengenes in the Dutch blood data (a) and the SAFHS blood data (b). The tables show the pairwise correlation coefficients (upper number) between the eigengenes and the correlation test p-values (lower number). The colors of the table entries color code the values of the correlations (green and red correspond to negative and positive correlations). Note that the four modules ME(blue/CTX), ME(yellow/CN), ME(yellow/CTX), and ME(blue/CB) were highly positively correlated with each other but negatively correlated with ME(green/CTX).