Fig. 2

Gene-to-gene analysis using BioLayout, showing relationship between genes. Nodes (spheres) represent genes and edges (lines) show correlation of greater than 0.90 between gene expression patterns across all samples, allowing the similarity of gene expression patterns across all samples to be examined. a. The largest element in the graph created by BioLayout from the expression profiles of genes across the breeds and disease status. Nodes of the same colour were allocated to the same expression cluster by the MCL clustering algorithm (inflation value 1.7) because they have similar expression patterns in the samples. b. Clusters showing differential expression according to sample type. The network layout is the same as for Fig. 2a but only the apparent differentially expressed clusters are shown. Histograms surrounding the network graph are coloured the same way as the nodes of that cluster and show the average expression of genes in the cluster. X axis shows the disease status of the valve; upper bar shows the grade of disease (Green − normal valves; Orange – Grade 3 diseased valves; red – Grade 4 diseased valves); lower bar shows the breed and valve status (green − normal valves; blue − non-CKCS diseased valves; red − CKCS diseased valves). Y axis shows average expression. Gene lists for these clusters and enlarged images of the histograms are presented in Additional file 1