Figure 3. Hierarchical clustering of the known miRNAs during different developmental stages using Pearson correlation.

Heatmap was constructed based on the log₁₀ of TPM value of miRNAs. Black indicated the expression value of the miRNA was 0 after normalization. Grey indicated that the miRNA was not detected in that library. TPM value for each tag was calculated by the sum of total clean reads which were within±2 bp variations of the mature miRNAs on the precursor.