Correlation of a fold-change gene expression value with a gene set-derived enrichment statistic can elucidate the function of poorly characterized gene products. A) Plot of fold-change gene expression values for the gene STYXL1 versus the enrichment statistics calculated using the WONG_MITOCHONDRIA gene set. Data points are derived from individual samples within the expO data series (see Methods). B) Plot of the fold-change expression values for DUSP6 versus enrichment statistics derived from the gene set ST_ERK1_ERK2_MAPK_PATHWAY. C) Heatmap of correlation statistics for the five gene sets that were most strongly associated with STYXL1 or DUSP6, as determined from all gene sets examined (N=4,438). The dendrogram on the left represents the overlap between the gene sets. The dendrogram was generated using dissimilarities between gene set compositions as previously described .