Validation of global AMD signature genes with an independent cohort. Using a support vector machine (SVM) and the 20 most significant genes in the RPE-choroid Global Up module (Figure 2a), a classification model for predicting AMD status was developed. (a) Expression heat map (log2 scaled, median-centered) of the genes/probes from the Iowa donor set used to generate the classification model. All donor ages are plotted under the heat map (yellow line indicates point at which donors become age-matched). (b) Results obtained using an AMD SVM model that incorporates expression data and age to identify AMD donors in: a subset of the Iowa data that was not used for training (that is, 'Test Set'), the Oregon dataset (that is, 'Validation Set'), and a randomized Oregon dataset (that is, 'Random Genes and Ages'). These results correspond to 'SVM Model 2 (+Age)', which is detailed along with other SVM models in Figures S9 and S10 in Additional file 1. Statistical significance was determined as described in Materials and methods.