The substitution ratio of the <i>MIR482-MIR1448</i> polycistron and <i>rDNA-ITS</i> regions.

The differences of the substitution ratio between functional regions (pre-miR482, pre-miR1448) and nonfunctional regions (5′ and 3′ flanking sequences) were extremely statistically significant (P value <0.0001, two-tailed t-test) and the differences of the substitution ratio between functional regions (pre-miR482, pre-miR1448) and internal regions were very statistically significant (P value <0.01, two-tailed t-test), while the differences of the substitution ratio between pre-miRNAs and ITS (ITS1 and ITS2) were not significant at the 5% level.