Receiver operating characteristic of all descriptor combinations for shuffled alignments. ROC curves of all descriptor combinations for shuffled alignments. Columns of test alignments were randomly permuted to create shuffled alignments. Corresponding AUC is given in brackets. ROC curves were computed by training a SVM model for each descriptor combination and testing the model on shuffled alignments by utilizing plotroc.py of the libsvm 2.8 package . Training was done with the original training set for RNAstrand. SVM parameter and kernel did not change, i.e. a radial basis function kernel with parameters C = 128 and γ = 0.5 were used.