The hpRNA/RNAi Pathway Is Essential to Resolve Intragenomic Conflict in the Drosophila Male Germline

摘要

Intragenomic conflicts are fueled by rapidly evolving selfish genetic elements, which induce selective pressures to innovate opposing repressive mechanisms. This is patently manifest in sex-ratio (SR) meiotic drive systems, in which distorter and suppressor factors bias and restore equal transmission of X and Y sperm. Here, we reveal that multiple SR suppressors inDrosophila simulans(NmyandTmy) encode related hairpin RNAs (hpRNAs), which generate endo-siRNAs that repress the paralogous distortersDoxandMDox. All components in this drive network are recently evolved and largely testis restricted. To connect SR hpRNA function to the RNAi pathway, we generatedD.?simulansnull mutants of Dcr-2 and AGO2. Strikingly, these core?RNAi knockouts massively derepressDoxand?MDoxand are in fact completely male sterile and exhibit highly defective spermatogenesis. Altogether, our data reveal how the adaptive capacity of hpRNAs is critically deployed to restrict selfish gonadal genetic systems that can exterminate a species.