Signal distribution and global similarity of samples. Panel A gives RNA quality data shown as a virtual gel as indicated. A green bar is the internal standard. Molecular weight markers are shown (MW). The fragment size is given in bases. Panel B shows box plots of log 2-transformed signal intensities (y-axis) for the testicular samples as indicated (x-axis) before normalization (wild-type samples from the B6129SF2/J background not shown ). Panel C summarizes the overall degree of expression data similarity using a color-coded distance matrix (white is identical, back is most dissimilar). A dendrogram (top and left) shows the pattern of sample clustering observed.