An illustration of plasmids, small circles of bacterial DNA NANOCLUSTERING/SCIENCE PHOTO LIBRARY/Alamy
Bacteria host bits of DNA that can replicate and spread to other bacteria. Now, researchers have discovered that these “selfish genes” wage war on their rivals using DNA-destroying CRISPR systems.
CRISPR has become famous as a way of editing genes, but in bacteria, CRISPR systems often act as an immune system, targeting and dismantling the DNA of invading viruses.
at the University of Copenhagen in Denmark and his colleagues have shown that some of the self-replicating bits of DNA in bacteria encode their own CRISPR…



