Fig. 4

Identification of P-element copies inserted into piRNA clusters (a) Genomic distributions of P-element insertion sites identified in the respective genomes (blue triangles). The height of blue triangles represents relative numbers of sequencing reads that supported insertion. Orange blocks show the piRNA [3]. Arrows indicate the active piRNA clusters harboring P elements. b The percentages of P-element reads identified in piRNA clusters in the total P-element reads. c Number of P-element copies in dual-strand (left) or unistrand (right) piRNA clusters. Active and low activity piRNA clusters are shown in orange and blue, respectively. Cluster names are shown with their rank of expression ability. The. + and - show the sense and antisense P-element insertion in relation to the transcription of the unistrand cluster