piRNA mapping pattern in protein-coding genes. (A) piRNA densities in the 5’UTR, CDS, and 3’UTR regions of 3’UTR piRNAs enriched genes. piRNA density in each region is shown in boxplot. For visual clarity, genes with normalized piRNA enrichment > 5 are not shown. (B) piRNA mapping density in 3’UTR piRNA enriched gene ELFN2 (Extracellular Leucine-rich repeat and Fibronectin type III domain containing 2). The genomic location of the locus, piRNA mapping density, and ENCODE gene annotation are shown. piRNAs mapped to the sense and antisense strand of the reference genome are shown in brown and blue, respectively. For gene annotation, exonic regions are shown as solid blue boxes, while non-exonic regions are shown as thin lines, with arrows indicating the direction of the gene. piRNAs predominantly mapped to the 3’UTR of ELFN2 in the direction of the gene (i.e., antisense to the reference genome).