Weights of the model trained on the sparse-19 representation of Shabalina et al.'s dataset. The picture shows the weights of the linear model estimated by the LASSO on the sparse-19 representation trained on the 653 siRNA compiled by Shabalina et al. . Each column corresponds to one position in the siRNA, numbered from 1 to 19 in the 5'→3' order the antisense strand, each row to a nucleotide of the guide strand. The color of a cell represents the weight associated with a given nucleotide at a given position: blue colors indicate a tendency to increase the efficacy of the siRNA, green colors a tendency to decrease it. A comparison of this picture with Figure 2 highlights the similarities and the differences of the LASSO model trained on independent datasets.