Somatic piRNAs in the adult mouse

Small RNAs were deep sequenced from the liver and spleen of adult mice in an effort to identify somatic piRNAs. Following sequencing of all small RNAs, known non-coding RNAs were computationally removed from the dataset. The remaining RNAs were then mapped to the genome and analyzed for sequence characteristics (5' base, length) typical of known piRNAs. To determine if any of the identified small RNAs were MIWI2 dependent, we deep sequenced small RNAs from liver and spleen of MIWI2 KO mice and analyzed them as above. We deep sequenced small RNAs from the liver and spleen of one WT mouse and one MIWI2 knock-out mouse. We then trimmed sequencing adapters and removed known ncRNAs (rRNA, tRNA, snoRNA, snRNA, miRNA) from the dataset before aligning reads to the mm9 assembly of the mouse genome.