Piwi-interacting RNAs (piRNAs) help defend host genomes against germline transposons. In this issue of Cell, Khurana et al. show how alterations in the piRNA-encoding loci within a single generation allow a naive fly genome to overcome the initially insurmountable challenge imposed by a newly encountered mobile element. © 2011 Elsevier Inc.
Levine, M. T., & Malik, H. S. (2011, December 23). Learning to protect your genome on the fly. Cell. Cell Press. https://doi.org/10.1016/j.cell.2011.12.001