The evolution of genic piRNA cluster loci expression patterns

This study examines the conservation of Piwi-interacting RNA (piRNA) clusters that come from protein coding gene transcripts. By sequencing small RNA libraries from gonad tissues of Drosophilids and Glires we discover a diverse set of genic piRNA clusters conserved across animals. This dataset reveals new expression patterns for genic piRNA clusters and examines whether changing piRNA expression patterns correlates with sequence changes in piRNA cluster genomic sequence across a variety of animal species. Overall design: We dissected gonad tissues consisting of ovaries from wildtype adult Drosophilids (D.melanogaster, D.erecta, D.yakuba, D.virilis) and testes from wildtype pre-pubsecent and adult mouse and rats. Adult testes from rabbits were purchased from Pel-Freez Biologicals. Total or immunopreciptated RNAs were extracted from the pulvirized gonad tissues of Drosophilids and Glires. Small RNAs were purified from these samples, converted into cDNA libraries, and sequenced on an Illumina HiSeq2000.