Sample clustering for the neural cell data of Kasowski et al. . A common variance function was estimated for all samples and used to apply a variance-stabilizing transformation. The heat map shows a false colour representation of the Euclidean distance matrix (from dark blue for zero distance to orange for large distance), and the dendrogram represents a hierarchical clustering. Two GNS samples were derived from the same patient (marked with '(*)') and show the highest degree of similarity. The two other GNS samples (including one with atypically large cells, marked '(L)') are as dissimilar from the former as the two NS samples.