Fig. 5

miRNAs are younger than their protein-coding gene targets. This histogram gives the number of human miRNAs (y-axis) for which a given fraction of their gene targets are younger than it (x-axis). On average, 92.5% of a miRNA’s gene targets are older than the miRNA itself; this is significantly more than would be expected from the differences in age distribution between miRNAs and genes (P < 0.001, permutation test). In the most common scenario, a miRNA is younger than all of its target genes