All hit sequences with no more than 3 mismatches were selected for further analysis. After removal of the repeated, tRNA, rRNA or protein coding sequences, prediction of the secondary structure of miRNA precursors was performed using RNAfold and MFold3.2. Criteria applied by Ambros et al. (2003) and Zuker (2003) were used to select potential pre-miRNAs. The various parameters of pre-miRNAs were employed to validate the candidate miRNAs.