Features of miRNA regulatory system in <i>O. sativa</i> and <i>A. thaliana</i>.

aTarget genes of de novo generated miRNA genes. bTarget genes of conserved miRNA genes. ct-test between target genes of conserved miRNA genes and all genes. dAverage level of all (target) genes. eAverage level of all (target) genes. fPercentage of (target) genes in segmental duplication blocks. gPercentage of (target) genes in tandem duplication arrays.