System flow of miRTar. miRTar system flow is composed of six parts. First, the various analyzing scenarios are designed. Second, data are collected from external database. Third, miRNA target sites are predicted. Fourth, exon/intron boundaries and alternatively spliced exon types are recognized. Fifth, the enrichment of the gene group is analyzed. Finally, a user-friendly graphical representation is designed to capture the regulation by miRNAs of genes.