mRNA-derived sense piRNAs predominantly arise from the 3’UTR regions. Percentage of reads mapping on both the entire mRNA (blue) and the 3’UTR only (red) of Anopheles transcripts of the analyzed samples indicate that piRNAs predominantly derive from the 3’UTR part. The figure shows reads mapping and size distribution of (A) whole male larvae, (B) blood fed ovaries and (C) larvae testis fragment as representative examples. (D) (left) Mapping of 26, 27 and 29-nt sized piRNAs from whole male larvae on the 3’UTR of AGAP003387. The nomenclature under each small RNA refers to its unique but arbitrary ID followed with a post-hyphen suffix indicating the normalized number of reads corresponding to that sequence in the sample (e.g. 55599–7 was a small RNA given ID 55599 that was cloned 7 times) The most abundant read is 29-nt long, was represented in 104,357 reads and is highlighted with a circle. (right) Size distribution of all the collapsed reads from whole male larvae derived from this 3’UTR showing that small RNAs of between 25 and 29 nt predominate. (E) Nucleotide frequency for each position of the collapsed reads derived from the 3’UTR of AGAP003387 indicate a prevalence of U at the first position.