Figure 1. Visual diagram of article contents. (A) Bulk RNA-seq data from 17 murine tissues (GSE132040) were sequentially filtered through 7 criteria. The funnel is a visual depiction of the filtering process. Steps 1–4 are adapted from previous publications. We added criteria filters 5 and 6 to ensure low variation and no correlation with age. Criteria filter 7 was validation of low variation and no age correlation, performed in a second dataset for 11 of the 17 tissues. The filtering strategy resulted in 9 pan-tissue age-invariant genes (gene box). (B) Sample gender, age and life stage distributions of the samples in the dataset. A full table of samples can be found in