Screen shots of ExpressionPlot 4way plots showing cross-platform and cross-species comparisons. (a) Heart-enriched gene expression in human tissue panel exon array  (x-axis) and RNA-Seq  (y-axis) data sets. Points correspond to genes. Fold-change of expression in heart is plotted versus all other samples in corresponding data set. Genes enriched in heart are plotted further to the right (exon array) and/or up (RNA-Seq), and those higher in other samples are further to the left and/or down. Genes significantly different only on one platform are colored red (exon array) or green (RNA-Seq) and those different on both platforms are colored blue. P-value cutoffs are 0.01 for exon array and 10-4 for RNA-Seq, and fold-change cutoffs are 2 for both platforms. Colored numbers show number of genes in each category. (b) Similar plot comparing the same x-axis (human heart-enriched gene expression by exon array) to mouse heart-enriched gene expression, also by exon array (y-axis).