Fig. 1: Frequency of miRNA-like simulated molecules that found at least one suitable target on 3’ UTRs of a given species.

The seed was conservatively defined as nucleotides 2–8 of the miRNA; a match was accepted if it was perfect at the seed and if it included a maximum of 5 mismatches outside. An example of an alignment with three mismatches is included in the insert. The number of elements with an acceptable match was normalized on the number of 22-mers in the relative 3’ UTR set and divided by the number of simulated pri-miRNAs. The y-axis is log-transformed for the sake of readability. Regression line details: y = 1.0757x − 12.8616; R2 = 0.9719; ***P < 2 × 10−16.