Figure 1.

Small RNA transcriptome analysis. (a) Small RNA‐seq data from four young (5 months), four old (24 months), and four very old (36 months) male mouse livers identified 56 miRNAs that change expression levels with age (p ≤ 0.05, FDR ≤ 0.05). The heat map shows the level of change ranging from a decrease (blue) of log₂ = −10 to an increase (red) of log₂ = 10. (b) Pie charts show the chromosomal origin of the miRNAs that change expression levels with age. Note that 40% and 70% of the miRNAs that change expression levels at 24 and 36 months, respectively, are located on the X‐chromosome. (c) Fifteen miRNAs located on the X‐chromosome showed an increase in expression between 44‐ and 968‐fold in 24‐month‐old and 36‐month‐old mice (p ≤ 0.0002, FDR ≤ 0.002). The numbers indicate the fold increase in expression over 5‐month‐old mice. Differential expression and significance were calculated using EdgeR software (Robinson, McCarthy, & Smyth, 2010)