Figure 2. Individual cataract scores and N-acetyl histidine (NAH) concentrations in lenses of the fish used for microarray analysis. The right lens of the fish was used for microarray analysis, and thus the cataract scores (on a scale from 0 to 4) of the right lens are presented in the graphs. The NAH concentrations were determined in the left lens of the same fish. A: Cataract scores and NAH concentrations for the individual samples are shown in this graph. Under the sample names, the sample clustering (obtained by hierarchical clustering of genes and samples, see Figure 4) is shown to relate individual cataract scores and NAH concentrations to gene expression patterns (the closer the samples are in the cluster tree, the more similar is the lens transcriptome). B: Lens NAH concentrations were significantly negatively correlated to the cataract scores of the right lens (Spearman rank test; r=−0.63, p<0.002, n=22).