Substitutions observed in pre-miR482 and pre-miR1448 in <i>Populus</i>, on the basis of the secondary structure of <i>Populus alba</i> clone P01.

The theoretical probability of substitution that converting one pair of complementary bases into another pair of complementary bases has been determined previously (Dixon and Hillis 1993) and listed in parentheses. Single and double substitutions were calculated for pre-miR482 and pre-miR1448 of 33 Populus species (clones) (22 materials in this study and 12 EST from NCBI). Single substitutions, P<0.0001 for MIR482; P<0.05 for MIR1448 (two-tailed Fisher's exact test).