Figure 5
Three types of Piwi-interacting RNA (piRNA) cluster. (A) Unistrand piRNA cluster; piRNAs are produced from only one genomic DNA strand. (B) Dual-strand piRNA cluster; piRNAs are produced from both strands of the same genomic region. (C) Bidirectional piRNA cluster; two unistrand piRNA clusters are arranged in a divergent manner.