GUDMAP gene expression summaries. A query for a gene, or list of genes, can be used to find where a gene(s) is expressed during development. The result of such a query returns a gene expression summary for that gene or genes. In this example, a query for Wnt4, Upk3a, Bmp2 and Wt1 has returned a list of four gene expression summaries, one for each gene. These summaries give an overview of the in situ and microarray gene expression data available for a gene. The microarray data are summarised as miniature heatmaps in the ‘Microarray expression profile’ column, which can be clicked to link to a more detailed heatmap page (see Fig. 3). The in situ data are presented as a simple bar chart, with the six coloured bars each representing an anatomical focus group [mesonephros (red), metanephros (green), lower urinary tract (purple) and early (pink), male (orange) and female (brown) reproductive systems]. A bar above the line indicates that the gene is present in that anatomy group, a bar below indicates that the gene is not detected. The bars link to lists of in situ entries (see Fig. 4). All in situ images for the gene are summarised in the image gallery (see Fig. 5), to which there is a link from the thumbnail in the ‘In situ expression images’ column. Expression summaries of many genes can be viewed at once, aiding quick comparisons of expression.