Discovery of Porcine MicroRNA by Solexa Sequencing Figure 3. Example of high frequency of miRNA sequence variations (isomiRs). Shown are the unique sequences and number of times this sequence was detected matching the pre-miRNA sequence of ssc-miR-1. The most frequent occurring miR-1 sequence is in accordance with the miRBase reference sequence. An example of a miR-1 isomiR not matching the genome is shown in the italic part of the figure. doi:10.1371/journal.pone.0016235.g003 PLoS ONE | www.plosone.org 5 January 2011 | Volume 6 | Issue 1 | e16235