Visualization of eQTL data. iHAT visualization of all 696 significant SNPs of all 500 patients together with metadata. Color is used to encode the type of SNP in the respective patient: green = the two alleles are identical to the reference sequence, yellow = one allele differs from the reference, red = both alleles are different with respect to the reference. Next to the SNP matrix, metadata is visualized using color to represent the respective value. The leftmost column shows the phenotype data 'affection', followed by 15 columns of expression data represented by a color-gradient blue-white-red of the 15 genes.