Figure 4. qRT–PCR validation of RNA-seq results. Comparison of differential expression values determined by RNA-seq (dark gray) and qRT–PCR (light gray) for 25 differentially expressed genes identified by Burrows-Wheeler Aligner (BWA) workflow. Error bars represent the standard error of the mean. Neural retina leucine zipper gene (Nrl) was not detectable by qRT–PCR and therefore are left blank in the graph. Note that Rhodopsin (Rho), guanine nucleotide binding protein, alpha transducing 1 (Gnat1), cyclic nucleotide gated channel alpha 1 (Cnga1), and nuclear receptor subfamily 2, group E, member 3 (Nr2e3) having average crossing threshold (Ct) values greater than 30 in the Nrl^−/− samples are considered extremely low to non-expressing.