Figure 2

Violin plot showing the expression levels of novel-identified and known miRNAs. The violin plot combines box plot and kernel density trace to describe the distribution pattern of a vector of data. The four violin plots were drawn according to the expression levels of 525 newly identified and 175 known miRNAs under the normal and cold-acclimated condition, respectively. Note that if the expression level of a miRNA was 0 under certain condition, we assigned it to 1 in order to make the log-transfer of the raw data.