Figure 3. Classical and novel RG performance in aging samples. (A) Aging RG status of classical reference gene by tissue. Some tissue-RG pairs are age-invariant (blue), and are therefore good RG candidates for aging studies, while others did not satisfy our filtering criteria (red). (B, C) Coefficient of variance (B) or age correlation (C) violin plots of valid classical RGs (green), novel pan-tissue age-invariant RGs, and invalid classical RGs (red). (D) Scatterplot comparing %CV and age correlation for each tissue-RG pair. (E) Scatterplot comparing RT-qPCR Gene RefFinder score and mRNA-seq %CV in heart and liver. RefFinder and %CV scores were calculated from in-house and public validation datasets respectively. RefFinder is a summary score of BestKeeper, NormFinder, GeNorm and comparative delta-Ct values (analysis of these scores can be found in