Pachytene Piwi-interacting RNAs (piRNAs) expressed in mammalian germ lines are abundant, but their evolution and function are not fully understood. Here, the authors find that pachytene piRNA loci are hotspots of structural variation, which underlies rapid piRNA birth, divergence, and loss.
- Yu H. Sun
- Hongxiao Cui
- Xin Zhiguo Li