SNP positions in polymorphic precursors. (a,b) Examples of conserved miRNAs (a) and novel miRNAs (b) with SNPs in pre-miRNA hairpins. The ID of the precursor is indicated above the corresponding model. Colors indicate the entropy of the sequence from red (low) to purple (high). The green bars represent the mature miRNA location. Arrows indicate SNP positions on each precursor.